Volume 52,2025 Issue 2

In Focus

• Geothermal geological characteristics, genetic model and resource potential of hot dry rocks in the Gonghe Basin, Qinghai

  ZHANG Linyou, LI Xufeng, ZHU Guilin, ZHANG Shengsheng, ZHANG Chao, WANG Huang, FENG Qingda, XU Wenhao, NIU Zhaoxuan, DENG Zhihui

  2025,52(2):399-415, DOI: 10.12029/gc20240226001

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  This paper is the result of geothermal geological survey engineering. Objective The Gonghe Basin, situated on the northeastern margin of the Qinghai–Tibet Plateau, is a significant experimental area for the exploration and development of hot dry rock (HDR) in China. The formation mechanisms of HDR within the Gonghe Basin remain controversial and have attracted considerable research attention. The current thermal state is of great significance for a deeper understanding the distribution patterns and formation mechanisms of high–temperature geothermal reservoirs. Methods In this study, extensive geophysical exploration and drilling data are integrated to describe the geological and geothermal architecture of the Gonghe Basin. A two–dimensional temperature field profile across the east–west axis is established through numerical simulation. Based on these results, the resource potential of HDR is assessed, and the key factors controlling HDR formation are analyzed. Results The Gonghe Basin hosts abundant HDR resources, with an estimated 2.48×10²¹ J within the depth of 5 km. The two–dimensional numerical simulation reveals significant temperature field variations between the eastern and western parts of the basin. The temperature field variations are consistent with the distribution of the basin's basement depth, which decreases from west to east. High–temperature anomalies are observed in the northeastern region, particularly around the Xinjie–Waliguan uplift belt. Conclusions On the basis of understanding the knowledge of predecessors, this paper proposes a comprehensive HDR formation mechanism from the perspectives of geological, geothermal, and geophysical backgrounds. The formation of HDR in the Gonghe Basin is controlled by multiple factors, including continuous heating by partial melting, heating and conducting heat by granite, heat controlling by neotectonic uplift and denudation, and heat preservation and accumulation by sedimentary covers.

• Tracer test study on artificial reservoirs in hot dry rock geothermal systems in the Gonghe Basin, Qinghai

  ZHU Guilin, LIU Donglin, ZHOU Yinzhu, BIAN Chao, CAO Yueting, FENG Qingda, ZHANG Linyou, XU Wenhao, NIU Zhaoxuan, DENG Zhihui

  2025,52(2):416-424, DOI: 10.12029/gc20231121002

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  This paper is the result of geothermal geological survey engineering. Objective Hot dry rock is a clean and vast geothermal resource. China Geological Survey has been continuously implementing China's first hot dry rock geothermal power generation and grid connection project in Gonghe, Qinghai since 2019. Hot dry rock reservoirs are dense and require fracturing to form a permeable interconnected fracture network, creating a reservoir capable of accommodating a certain scale of heat exchange and water conduction. However, research on artificial reservoirs in high–temperature hard rock is relatively limited. Methods The successful construction of artificial reservoirs and effective inter–well communication are the core of successful hot dry rock development. Tracer tests are an effective means to study the above issues and characterize reservoir hydrogeological conditions. This study focuses on the hot dry rock test site in the Gonghe Basin of Qinghai, selecting sodium fluorescein and sodium bromide as tracers, and conducting tracer tests before and after large–scale fracturing. Results Before large–scale fracturing, tracer recovery rate and heat exchange volume were relatively low. After the transformation, reservoir fractures became more complex, reservoir connectivity improved, and the tracer recovery rate reached 14.14%. The heat exchange volume of fractures increased to 27 times, and the fractures became relatively homogeneous, effectively reducing the risk of heat breakthrough. Conclusions Tracer experiments can quantitatively evaluate the effectiveness of hot dry rock artificial reservoir fracturing. The research results have guiding significance for the conduct of hot dry rock tracer tests and the scientific development of high–temperature hard rock thermal storage.

• In–situ stress characteristics and fault stability analysis of hot dry rock GR2 well in the Gonghe Basin, Qinghai

  CHEN Dongfang, YANG Yuehui, NIU Zhaoxuan, WANG Hongwei, JIN Xianpeng, LI Zhenyu, WU Haidong, LIU Donglin

  2025,52(2):425-437, DOI: 10.12029/gc20230901003

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  This paper is the result of geological survey engineering. Objective The magnitude and direction of in–situ stress are important parameters for well placement, fracturing design and reservoir evaluation in hot dry rock development. It is of great significance to study reservoir stress state for hot dry rock development. Methods In this paper, the characteristics of current stress field in the Gonghe Basin are analyzed based on regional geological structure evolution, focal mechanism solution and inversion results, statistics of joints and fissures, and in–situ stress measured data. Combined with the reservoir structure and stratigraphic lithofacies characteristics of GR2 well, a three–dimensional model is established, and the three–dimensional in–situ stress data of GR2 well in the Gonghe Basin is obtained through numerical simulation by using orthogonal anisotropic elastic constitutive relation. The regional tectonic stress field and occurrence conditions of dry hot rock resources are discussed. Results ① The simulated stress distribution is consistent with the theoretical value, which meets the requirements of initial displacement accuracy, and finally predicts the distribution characteristics of in–situ stress field in the well. ② In the depth range of 500~4500 m, the relationship of three principal stresses is principal stress is σ_v>σ_H >σ_h, indicating that the stress structure in this region is favorable to normal fault activity. ③ The maximum horizontal principal stress direction of the Gonghe Basin in Qinghai province is mainly NE direction compression deformation, which is conducive to low fluid permeability and low heat transfer of granite. ④ Under the action of a unified regional stress field, the faults may be come instability near the injecting well, when the continuous injection pressure on the ground reaches or exceeds about 19.9 MPa during the water injection development of 3900~4500 m depth in the study area, leading to the occurrence of medium and small earthquakes, which should be prevented in the development and utilization of the hot dry rock. Conclusions The research results have certain reference value for geodynamics research and the safe development and utilization of dry hot rock in the Gonghe Basin.

• Deep–seated granite thermal reservoir exploration and hot dry rock potential assessment in the Qiabuqia Area, Gonghe Basin, Qinghai: A time–frequency electromagnetic method approach

  CHENG Zhengpu, WEI Qiang, LIAN Sheng, ZHANG Haijiang, HU Wenguang, MI Xiaoli, LEI Ming, LI Shu, YU Lei

  2025,52(2):438-451, DOI: 10.12029/gc20231115001

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  This paper is the result of geothermal geological survey engineering. Objective The Qiabuqia area within China's Gonghe Basin represents a key research zone for granite–hosted hot dry rock (HDR) systems. This study systematically investigates the caprock thickness variation and granite basement topography while elucidating the spatial configuration of granitic bodies to establish predictive models for HDR reservoir distribution. Methods Innovatively applying the Time–Frequency Electromagnetic (TFEM) method–traditionally employed in deep hydrocarbon exploration – to HDR characterization, we implemented a comprehensive workflow encompassing advanced data preprocessing, electrical parameter optimization, and constrained inversion modeling. Integrated interpretation of resistivity profiles with multi–source datasets (geological mapping, borehole logs, and auxiliary geophysical surveys) enabled three–dimensional reconstruction of stratigraphic architecture, granitic intrusion geometry, and HDR reservoir characteristics. Results (1) TFEM demonstrates exceptional capability in resolving electrical stratigraphy within 10 km depth. Resistivity profiles reveal a tripartite H–type structure comprising a sub–high–resistivity superficial layer (900–1400 m thickness, eastward–thinning), an intermediate conductive zone, and a high–resistivity basement. Granitic bodies exhibit A–type resistivity progression with depth, featuring westward–deepening top surfaces (–900 to –2900 m elevation). (2) Thermal logging–constrained models delineate distinct spatial configurations of the Qiabuqia and Dalianhai HDR reservoirs, demonstrating strong correlation with structural highs. Conclusions (1) Thermo–structural analysis identifies competent batholiths and stocks as preferential heat flow conduits, serving as prime HDR exploration targets. (2) This leads to the distribution characteristics of granitic bodies, which are deep rock bases, middle rock strains and shallow rock beds. (3) Resistivity anomalies within granitic masses reflect structural integrity gradients, with batholiths and stocks exhibiting superior mechanical continuity compared to fractured sill complexes.

• Research on three–dimensional seismic attribute fusion technology for characterizing fractures in granite geothermal reservoirs

  LIAN Sheng, CHENG Zhengpu, WU Junjun, DONG Jinwei, TIAN Puyuan

  2025,52(2):452-461, DOI: 10.12029/gc20231213002

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  This paper is the result of geothermal geological survey engineering. Objective It is necessary to predict the characteristics, spatial distribution and density of natural fractures in granite reservoirs using high–precision seismic data and feature analysis methods, which provide scientific evidence for the construction of Enhanced Geothermal System (EGS). Methods This study adopted advanced 3D seismic techniques, including wideband, wide–angle, high–density sampling, as well as advanced processing methods such as structural–oriented filtering and multi–window dip scanning. The application of these techniques greatly improved the signal–to–noise ratio of seismic data, further optimizing the detection effect of the granite interior. At the same time, this study also combines 3D seismic attributes such as seismic attribute volume, maximum likelihood volume, coherence volume, curvature volume, variance volume, and ant volume with multi–azimuth constraints to accurately predict the spatial distribution density of fracture clusters. Results Through comprehensive attribute analysis and drilling imaging logging results, we reveal the regularity of the development of northeast and northwest fractures in granite–type hot dry rock reservoirs. These results are highly consistent with drilling imaging logging results, further verifying the accuracy and reliability of this research method. Conclusions This study successfully predicted the characteristics, spatial distribution, and density of natural fractures in granite–type hot dry rock reservoirs through high–precision seismic data and feature analysis methods. This method provides important evidence for fracture detection, drilling deployment, and mining plan determination in EGS engineering construction.

Reviews

• Stability of global critical mineral supplies: Trends, hot topics, and further outlook

  TANG Jinrong, ZHANG Yuxuan, XU Li, NIU Yazhuo, REN Jigang, YU Rui

  2025,52(2):462-481, DOI: 10.12029/gc20240825001

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  This paper is the result of mineral exploration engineering. Objective The global energy transition and the rapid development of emerging industries have heighten the importance of securing a stable supply of critical minerals, which are essential for economic and technological transformation. This issue has garnered significant attention from governments and multinational enterprises, becoming a focal point in earth sciences research. Methods Through a systematic analysis, this paper examines the latest trend of global supply of critical minerals, identifies emerging research hotspots, and offers insights into future development. These findings provide valuable guidance for China's strategic planning in critical minerals and resource security. Results This study reveals that the stability of global critical minerals supplies has received a great deal of attention from the world's major economies and important manufacturing companies. The leading role of governments in shaping the supply chain of key minerals and the industrial chain is becoming increasingly evident. The methodology for determining critical list is evolving, the number of mineral species is expanding, but the overlapping mineral species are becoming more and more aggregated. With deeper research into mineralization processes and the occurrence of critical minerals, new deposit types are emerging. Manufacturing enterprises and mining enterprises are interfacing more closely, with a clear trend towards upward and downward integration, and investment institutions are increasing their support for investment in key minerals and research and development of new technologies. Conclusions As energy transition efforts intensify, the importance of critical minerals will continue to grow in the energy transition, driving increased demand, investment, and resource discovery. Notably, smaller critical minerals, such as lithium, may gain significance and emerge as major resources. Resource–rich nations like Australia and Canada are strengthening their supply advantages, while lost regions such as Central Asia and Europe are reasserting their roles in the market, marine mineral resources exploration and development on the agenda. The global supply landscape is likely to become more diversified. Advances in technology, innovations in alternative processes, and the iteration of recycling technology will open new avenues for the securing critical mineral supplies.

• Metallogenic characteristics and exploration development status of lithium deposits in Africa

  WANG Qiushu, LI Wen, CHEN Qishen, CHEN Xiufa, ZHANG Yanfei, LI Yujie

  2025,52(2):482-494, DOI: 10.12029/gc20221130001

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  This paper is the result of mineral exploration engineering. Objective Under the background of the global carbon neutral and the green energy transition, lithium has become a global consensus as a key mineral. The exploration and development of Lithium resources in Africa have put on the agenda. To provide reference for international cooperation of Lithium industry in Africa, we analyze the metallogenic characteristics and exploration and development potential of Lithium deposits in Africa. Methods The paper summarizes the metallogenic characteristics of Lithium resources, and analyzes the development prospects of Lithium industry by tracking the exploration and development trends of lithium resources in Africa. Results Africa's proven resources are mainly LCT pegmatite deposits, distributed in the lithium rich pegmatite belt of Congo (DRC), Mali, Zimbabwe, Ghana and Namibia, which are characterized by large resources, high grade and favorable development conditions, so that it is attracting the investment of mining companies from Australia, China and the UK. Conclusions Africa has a late start in lithium exploration and slow development progress, but has good resource endowment. The current high–quality resources have been locked in advance, and it is expected to become a new growth point of global lithium resource supply in the future.

• Distribution characteristics, genesis types, current status of resource application of barite deposits in China and its prospects

  ZHANG Yiting, ZHONG Yijiang, WANG Chunlian, LI Mengfan, ZHANG Shupeng

  2025,52(2):495-512, DOI: 10.12029/gc20231012003

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  This paper is the result of mineral exploration engineering. Objective Barite, as a dominant mineral resource in China, faces challenges such as low utilization efficiency. To ensure the security of China's barite resources, it is essential to further explore and develop barite reserves. This effort is of significant importance for supporting the development of the petroleum exploration industry and broadening its application fields. Methods This paper summarizes the metallogenic epochs, characteristics, genetic types, and material sources of barite deposits. Meanwhile, it systematically reviews the distribution, resource status, and applications of barite in China. This work provides a reference for future mining and application of barium sulfate in China. Results The genetic types of barite deposits in China can be classified into sedimentary, volcanic-sedimentary, hydrothermal, stratified hydrothermal, and weathering residual-slope accumulation types. Based on the sources of metallogenic fluids, barite can be divided into two end–members: submarine hydrothermal barite and biogenic barite. Globally, the proven reserves of barite are approximately 740 million tons. In China, barite is produced in 26 provinces, including Guizhou, Guangxi, Hunan, and Fujian. As one of China's critical minerals, it ranks as the world's second–largest producer, characterized by high–grade deposits and significant export volumes. Barite is widely used in various fields such as the oil and gas industry, advanced materials, medical treatment, military, and environmental protection sectors. Conclusions Barite deposits in China primarily formed during the Paleozoic and Mesozoic eras，with key regions including the Jiangnan, Qinling, and Guizhou–Guangxi areas, dominated by sedimentary–type deposits. The sources of barite metallogenic fluids for barite are diverse. Geochemical signatures indicate that the metallogenic materials originate from submarine hydrothermal fluids, while biomarker compounds and heavier sulfur isotopes indicate a biogenic origin. As one of the crucial advanced materials, barite requires a focus on enhancing its deep processing capabilities, developing its strategic emerging industries, and expanding its application fields within the framework of future intensive, efficient, and green industrial development mechanisms. The future prospecting potential for barite in China should focus on the following aspects to discover more abundant barite resources: Firstly, emphasis should be placed on exploring super–large and large barite deposits in the southern margin of the Yangtze Platform. Secondly, the exploration of low–grade barite deposits and associated barite deposits, similar to those in the Gansu–Qinghai–Ningxia barite metallogenic region, should not be overlooked. Finally, continuous exploration and development in regions such as North China and Xinjiang.

• Research progress of InSAR technology application on landslide identification and monitoring

  TAO Changxu, ZHANG Yongshuang, REN Sanshao

  2025,52(2):513-526, DOI: 10.12029/gc20240515001

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  This paper is the result of geological survey engineering. Objective Landslides pose a significant risk to major constructions and human safety in mountainous areas, and the early identification and monitoring of landslide has become an important way to prevent risk. Methods This paper briefly introduces the basic principle of InSAR technology and its development history, and introduces the current research status of its application in landslide identification and monitoring. Results The three types of landslide InSAR identification are regional, key sections and single landslide. InSAR monitoring of landslides mainly focuses on large landslides with significant risk, and highlights the research progress in monitoring method and early warning modeling. On this basis, the main challenges faced by InSAR technology in landslide identification and monitoring research at this stage are pointed out, including: the challenge of geometrical distortion in side–view imaging under complex terrain conditions, detecting large gradient deformation of landslides, atmospheric delays and vegetation penetration, etc. InSAR technology in landslide application still exists problems such as insufficient capacity of large–scale monitoring, low degree of automation of processing process, and insufficient degree of data analysis and mining. Conclusions The future development direction of InSAR technology in landslide identification and monitoring is prospected. With the continuous improvement of the application level of InSAR technology, it will effectively promote the new leap in landslide disaster risk prevention.

• Research progress and prospect of oxygen isotope technique in soil–vegetation–ecology–environment studies

  YE Guiqi, JI Wenbing, YANG Zhongfang, YU Tao, HOU Qingye, QIAN Kun

  2025,52(2):527-573, DOI: 10.12029/gc20240410003

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  This paper is the result of environmental geological survey engineering. Objective Oxygen is one of the basic elements that make up living matter, and the oxygen cycle in nature is the basic guarantee for life activities. Oxygen isotope technology is a powerful tracer that can effectively indicate biogeochemical cycling processes and has been widely used in ecological and environmental research. Methods This paper reviewes the fractionation mechanism of oxygen isotopes and its application in soil–vegetation–ecological environment by reviewing a large number of literatures on oxygen isotopes. Results Depending on the large isotope mass ratio difference, oxygen isotopes can undergo the greatest degree of isotope fractionation under natural conditions. The application of oxygen isotopes mainly includes three aspects: (1) Tracing the source of environmental pollutants; (2) Paleoenvironment and paleoclimate restoration; (3) Tracing the geographical origin of food (animals). Conclusions In practice, oxygen isotopes are usually used together with other isotopes (hydrogen, carbon, nitrogen, etc.) to track multi-dimensional climate, vegetation development, and geographical location. In the future, oxygen stable isotopes can be combined with substitute models in the fields of global change, such as tree rings, foraminifera, loess, and salt lakes, and play a more important role in environmental ecology research.

• Reviews on apatite and its application in the field of ore deposit geology

  LI Jiang, MA Zhenbo, YANG Yan, HUANG Jianhan, ZHANG Rongzhen, HAN Jiangwei

  2025,52(2):574-596, DOI: 10.12029/gc20240313001

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  This paper is the result of mineral exploration engineering. Objective Apatite is a mineral commonly present in igneous, metamorphic, and sedimentary rocks. Its crystal structure can host various elements such as Sr, Mn, REEs, U, Th, F, Cl, and others. Apatite's chemical composition is dictated by magma and hydrothermal processes, which makes it a subject of interest for many researchers. Methods This paper reviews common methods and the latest research achievements of apatite in mineralogy, isotope chronology, deposit geochemistry, artificial intelligence, and exploration indication. Results Elemental (e.g., Sr, Y, and REEs) and Sr-Nd isotopic compositions of magmatic apatite can help identify the source of its parental magma. Elements such as Ce, Eu, Ga, and Mn can indicate the oxidation state of the magma, while F and Cl can be used to estimate the volatile content of the melt. The U-Pb isotope system of apatite can record the crystallization age of its host rock. Low-temperature thermochronology is often used to study the degree of denudation after ore deposit formation. Hydrothermal apatite's structure and composition bear information about the fluid, which can indicate the fluid source, properties, and other information related to magmatic-hydrothermal mineralization processes. Artificial intelligence techniques such as machine learning can process massive amounts of apatite data to discriminate rock types and deposit types. Conclusions Apatite is a mineral that is crucial for studying mineral deposits and exploring ore deposits. Future researches should focus on the relationship between hydrothermal apatite and the metallogenic process. Additionally, combining artificial intelligence with apatite analyses to trace the diagenetic and metallogenic process is a promising avenue for further study.

Research Articles

• Enrichment mechanism, optimization and evaluation of favorable CBM areas in the Upper Permian of Northwest Guizhou

  LI Honglei, GUO Zhijun, YI Tongsheng, QIN Yong, YANG Tongbao, JIN Jun

  2025,52(2):597-612, DOI: 10.12029/gc20220612002

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  This paper is the result of energy exploration engineering. Objective The primary goal is to identify and classify favorable areas for CBM exploration and development, providing a scientific basis for future exploration efforts in Guizhou Province. Methods Based on geological exploration data and laboratory sample analyses, key reservoir characteristics of the major coal seams (No. 6, No. 14, and No. 27) were systematically assessed. Parameters such as coal seam thickness, gas content, permeability, reservoir pressure, and coal–body structure were analyzed. Using a five–index evaluation method, 19 gas–bearing areas were classified. Results (1) The three major coal seams exhibit greater thickness in the southwest and thinner deposition toward the northeast. The average gas content is 11.73 m³/t, with gas accumulation primarily controlled by synclinal structures. (2) Seven extensive gas–bearing areas were identified, with the Bide–Santang Basin and the Jinlong–Qianxi–Jinsha syncline group exhibiting gas contents exceeding 16 m³/t. (3) The average well–tested permeability of the coal seams is 0.173 mD, indicating a medium–low permeability reservoir. Permeability decreases from west to east and with increasing depth, with significant variations across different seams. (4) The average reservoir pressure is 4.98 MPa, with an average pressure coefficient of 0.86, indicating a predominantly underpressured state. A transition from underpressure to normal and overpressure is observed from east to west. (5) Coal structural characteristics vary spatially, with primary and fragmented coal types dominant in the east, while granulated and pulverized coal types are more prevalent in the west. Conclusions Based on the evaluation, seven Grade I, eight Grade II, and four Grade III favorable CBM areas were identified. The Grade I areas, including the Tucheng, Yangmeishu, Dahebian, Shuigonghe, Bide, Zhitang, and northern Jinlong synclines, demonstrate significant CBM exploration and development potential. The Grade II areas include the Gemudi, Jinpen, Santang, northern Qianxi, Jinsha, Liuchang, and Molaoba synclines, while the remaining synclines are classified as Grade III.

• Lithofacies paleogeography during the depositional period of the Nanhua System Datangpo Formation and its indications for hydrocarbon accumulation in the Middle and Upper Yangtze Region, South China

  SONG Teng, LIN Tuo, LI Fei, LI Haohan, WU Hai, DUAN Ke

  2025,52(2):613-630, DOI: 10.12029/gc20210602004

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  This paper is the result of oil and gas exploration engineering. Objective The marine black manganese–bearing carbonaceous shale of the Datangpo Formation, widely distributed in the mid–Neoproterozoic Nanhua strata of the Middle–Upper Yangtze Region, South China, has been extensively studied as a manganese deposit but remains poorly investigated regarding its petroleum geological characteristics. This study systematically analyzes the lithofacies paleogeography of the Datangpo Formation and evaluates its implications for hydrocaron accumulation, providing critical insights for guiding petroleum exploration in the southern China. Methods Through field surveys and comprehensive data synthesis of the Datangpo Formation, we systematically evaluated hydrocarbon conditions, source rock geochemistry, and reservoir–caprock assemblage, especially lithofacies and paleogeography. This integrated approach combined individual well log interpretation, multi–well correlation analysis, and lithofacies paleogeographic with advanced analytical techniques including organic geochemical testing, petrophysical characterization, and reservoir evaluation. Results The Datangpo Formation developed during an interglacial period, with its depositional architecture constrained by extensional riftdynamics. Sedimentary facies within the formationare classified into two principal types, seven subcategories and multiple microfacies. The sequence comprises a complete transgressive–highstand–regressive cycle. Hydrocarbon–prospective facies are limited shelf subfacies and lagoon subfacies, predominantly occurring in the first member. These intervals exhibitfavorableorganic geochemical index, and constitute potential source rock horizons. Conclusions The first member of the Datangpo Formation exhibits significant hydrocarbon–generation potential and viable shale gas prospects. Strategic areas including Songtao, Huayuan, Xiushan, Xiangtan and Hefeng, located at the confluence of Hunan, Chongqing and Guizhou Province, demonstrate favorable geological conditions for shale gas exploitation. This unit serves as a competent source rock capable of forming multiple prospective hydrocarbon reservoir assemblages. Notably, The Xiushan–Songtao–Huayuan sector along the tri–province boundary of Chongqing, Guizhou, and Hunan exhibits optimal source–reservoir coupling configuration, indicating promising targets for conventional petroleum exploration.

• Development stage of Jurassic Che–Mo Paleouplift in the Junggar Basin and its constraints on sedimentary system

  KONG Jiahao, ZHANG Guanlong, XU Shumei, WANG Jinduo, ZENG Zhiping, WANG Qianjun, REN Xincheng, WU Xiangfeng, SHU Pengcheng, MA Huilei, CUI Huiqi

  2025,52(2):631-649, DOI: 10.12029/gc20220322001

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  This paper is the result of oil and gas exploration engineering. Objective Che–Mo synsedimentary paleouplift in Junggar basin is an important geomorphic unit that affects the structural style and reservoir distribution characteristics of Jurassic. The study of its development process is helpful to understand the basin mountain coupling relationship and the accumulation law of oil and gas reservoirs in Junggar basin. Methods Based on the logging data and seismic data of 41 wells in the abdomen of the basin, this paper makes a detailed analysis and isochronous comparison of Jurassic sand body and stratigraphic structure, and focuses on the synergistic evolution between the phased development of Che–Mo paleouplift and the orogenic belt around Junggar basin, especially Bogda mountain, and its influence on the basin boundary and sedimentary pattern. Results The evolution of Che–Mo paleouplift can be divided into three stages: initial development stage, rapid uplift stage and post uplift denudation stage. The initial development stage of Early Jurassic Che–Mo paleouplift has no or little influence on the distribution and structural style of Badaowan Formation and Sangonghe Formation. The study area is supplied by Zhayier mountain in the northwest and Kelameili mountain in the northeast, mainly forming braided river delta sedimentary system; The Middle Jurassic was the rapid uplift stage of Che–Mo paleouplift. In addition to the source supply of Zhayier mountain in the northwest and Kelameili mountain in the northeast, Bogda mountain also rose out of the water at the same time and began to supply the source, resulting in significant changes in basin boundary, stratigraphic distribution and structural style, resulting in large–area overlap of the first and second members of Xishanyao Formation, loss or denudation of the third members of Xishanyao Formation, The sedimentary system combination of Braided River Delta and beach bar is formed; The uplift of Che–Mo paleouplift in late Middle Jurassic and late Jurassic resulted in the denudation loss of Toutunhe Formation and Qigu Formation, forming a regional unconformity with Cretaceous. Conclusions The formation and evolution of Che–Mo paleouplift in Jurassic not only affected the sedimentary landform of the basin, but also significantly changed the basin boundary and provenance pattern, and led to significant changes in sedimentary system, stratigraphic structure style and distribution law.

• Characteristics of Middle Jurassic overpressure and tight gas accumulation in Shengbei Sub–sag, Turpan–Hami Basin, Xinjiang

  XU Wen, RAO Song, WANG Xiaolong, XIAO Qilin, WAN Zexin, BAO Yiyao, LIU Yukun, TAO Ze, SHE Jiachao, SHI Xiang, CHENG Tian, JIANG Jilian

  2025,52(2):650-664, DOI: 10.12029/gc20220604002

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  This paper is the result of oil and gas exploration engineering. Objective The tight gas in the Shengbei subsag of the Turpan–Hami Basin has become an important field for expanding new exploration battlefields and discovering new reserves. The development characteristics and accumulation mechanism of tight reservoirs have become one of the key scientific issues that need to be solved urgently. Methods Using comprehensive research methods such as geochemistry, geophysics and oil and gas geology, the characteristics and accumulation stages of tight gas sources and reservoirs in the Middle Jurassic were systematically analyzed, and characteristics of overpressure development and the controlling effect on tight gas accumulation were determined. Results (1) The organic matter type of the main source rocks is mainly type III kerogen, and the whole is in the mature stage dominated by gas generation. Middle Jurassic developed low porosity and low permeability–low porosity and ultra–low permeability tight reservoirs, with an average porosity of 7.1% and an average permeability of 0.074×10^–3 μm². The pore type is dominated by secondary dissolution pores, while clay mineral interlayer pores, pyrite intercrystalline pores and micro–fractures are developed. (2) The Middle Jurassic developed overpressure caused by pressure conduction and hydrocarbon generation pressurization. The pressure coefficient was mainly distributed between 1.2 and 1.5. The overpressure top interface was located in the middle and upper part of the Qiketai Formation vertically. The overpressure is mainly distributed in the east and southeast of the Shengbei subsag, and the fault system controls the distribution range of the overpressure. (3) The hydrocarbon expulsion from source rocks lasted for a long time. From Late Triassic to the present, there have been at least two main periods of natural gas charging, and the two main accumulation periods are: Late Jurassic to Early Cretaceous and Paleocene to date. Conclusions The Middle Jurassic tight gas reservoirs are dominated by the accumulation model of "two–stage accumulation from far–source and near–source, pressure–fault coordinated transport, and fault–overpressure coordinated control". The research results in this paper will provide scientific basis and technical support for tight gas exploration and development in Shengbei Sub–sag.

• Mechanism of organic–rich shale formation and shale gas enrichment in the Carboniferous Tian'eping Formation from the Xiangzhong Depression

  CHEN Xiaohong, SHI Wanzhong, TIAN Wei, HE Hongsheng, LI Hai

  2025,52(2):665-679, DOI: 10.12029/gc20210816001

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  This paper is the result of oil and gas exploration engineering. Objective Through the study of shale formation and shale gas enrichment mechanism, the current study aims at finding out main factor controlling shale gas reservoir in the Carboniferous Tian’eping Formation in the Xiangzhong Depression as well as its enrichment patterns. Methods Carbonates carbon and oxygen isotopes as well as shale trace elements and major elements were analyzed at Well Xiangxindi 4 in order to recover paleo–environment and investigate the origin for the shale formation. Combined with the thermal evolution simulation of medium–low maturity shale gas reservoirs, the mechanism for shale gas enrichment is identified through petromineralogy, organic geochemistry, physical properties of shale gas reservoirs, existence forms of shale gas and tectonic preservation condition. Results (1) The organic–rich shale in Lower Carboniferous Tian’eping Formation were formed due to seawater stratification and seabed anoxia caused by the intensive climatic fluctuations in the Early Carboniferous. (2) The extensive and intense magmatic events in central Hunan led to the increase of locally paleogeothermal gradient and further caused secondary hydrocarbon generation in the Lower Carboniferous organic–rich shale. Shale gas in the Tian’eping Formation was formed owing to crude oil cracking and secondary hydrocarbon generation of organic matter. (3) Shale gas preservation was promoted due to decollement in the Ceshi Formation of the lower Carboniferous blocking the vertical escaping channel of the shale gas from the underlying Tian’eping Formation. Conclusions The shale gas of Lower Carboniferous Tian’eping Formation in Xiangzhong Depression is the common result of favorable facies zone controlling the total organic carbon content, magmatic thermogenesis controlling the reservoir physical properties and detachment structure controlling the preservation.

• Quantitative evaluation of shale brittleness based on statistics: Taking shale of Niutitang Formation in Western Hubei as an example

  LI Juan, WANG Shengjian, TIAN Yukun, ZHOU Hui, LIU Ce, XUE Zongan

  2025,52(2):680-690, DOI: 10.12029/gc20210407003

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  This paper is the result of geological survey engineering. Objective The brittleness of shale reservoir is one of the parameters reflecting the fracturing quality of shale gas reservoir, which has an important influence on the degree of difficulty of fracturing and the shape of fracture network. Methods In order to accurately evaluate the brittleness characteristics of Niutitang Formation shale reservoir in Western Hubei, systematic sampling, whole rock mineral and clay content test, main and trace element content test, acoustic mechanics joint test and other analytical tests were carried out on five wells in the south wing of Huangling anticline in Western Hubei. The quantitative evaluation of shale brittleness was carried out by cluster analysis and principal component analysis. Results There is a close relationship between minerals and rock brittleness, and the cluster analysis method can quantitatively characterize the effective brittle mineral composition and non–effective brittle mineral composition in shale; The comprehensive quantitative evaluation formula of brittleness index based on rock mechanics, mineral composition and element composition is established by using principal component analysis method, which overcomes the limitation of single method and forms the brittleness index profile of Niutitang Formation shale section in Western Hubei. Conclusions The results of microseismic monitoring and fracturing show that the newly established brittle index profile can accurately indicate the high brittle layer of shale, and the fracturing effect is good.

• Genesis analysis of slit–type carbonate gas reservoir in the Lower Silurian Shiniulan Formation in Wulingshan area

  ZHANG Jie, WEI Hongxia, WANG Shuangqing, SHEN Bin, PANG Fei, LI Menglai, YANG Liu

  2025,52(2):691-703, DOI: 10.12029/gc20200928002

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  This paper is the result of geological survey engineering. Objective Multiple sets of marine source rocks such as Cambrian–Ordovician, Silurian, Carboniferous–Permian, etc. are widely distributed in the northern Guizhou area of China, which have a good source–reservoir–caprock combination vertically and are of great natural gas resource potential and prospects for exploration and development. In order to better assess the natural gas resources in the area, on the basis of the discovery of the "four–story" composite natural gas reservoir in Anye 1 Well of the Anchang syncline in the Wulingshan area, northern Guizhou, this paper discusses the genesis of the Shiniulan Formation gas reservoir in the Anchang syncline. Methods Field geological works and indoor studies, geological probes and geochemical analyses, macroscopic observations and microscopic techniques, as well as literature researches were carried out. Results It is considered to be a slit–type carbonate gas reservoir, the gas is mainly derived from the underlying Longmaxi Formation, and the multiple stage tectonic movements in the area provided the driving force for its accumulation. Conclusions This research is significant for natural gas resources assessment of the region, and is also helpful for enriching and developing the theory of hydrocarbon accumulation in complex structural belts.

• Competitive adsorption characteristics and diffusion process of CO₂–CH₄ on mineral surface: A case study of the 2^nd section of Shanxi Formation in Yan'an Gas Field

  LIN Jin, WANG Xinwen, WANG Xiangzeng, HE Qingcheng, MENG Xiangzhen, Lü Min, WANG Quanbo, YANG Lichao

  2025,52(2):704-713, DOI: 10.12029/gc20230813002

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  This paper is the result of environmental geological survey engineering. Objective The CO₂–Enhanced Gas Recovery (CO₂–EGR) technology significantly augments natural gas extraction efficiency while concurrently facilitating the permanent subsurface sequestration of CO₂. This dual benefit substantially aids in achieving carbon neutrality goals. The mechanisms pivotal to enhanced recovery and storage include the competitive adsorption and diffusion of CO₂–CH₄ within nanopores. Methods This study focuses on the 2^nd section of Shanxi formation in the Yan'an Gas Field located in the Ordos Basin. Using molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) methods, a model was established toinvestigate the competitive adsorption behaviors of CO₂–CH₄ mixed gases in the nanoporous matrices of key minerals, specifically quartz and illite, under reservoir–specific temperature and pressure conditions. Additionally, the study analyzes the correlation between the self–diffusion coefficient of CO₂ and the variabilities in temperature and pressure. Results The study yields several findings: (1) At an isothermal condition of 353.15 K and varying pressures from 5.9 to 17.7 MPa, both quartz and illite exhibit heightened adsorptive capacities for CO₂ in comparison to CH₄. Furthermore, the competitive adsorption selectivity for CO₂–CH₄ is found to be greater in quartz pores than in illite pores. (2) Under similar isothermal conditions and at a constant pressure of 11.8 MPa with temperatures ranging from 313.15 K to 373.15 K, the competitive adsorption selectivity for CO₂–CH₄ in both quartz and illite pores is observed to diminish with increasing pressure and temperature. (3) Under conditions of low pressure (5.9 MPa) and high temperature (373.15 K), there is an enhancement in the mobility and diffusion efficiency of CO₂ within both CO₂–CH₄–quartz and CO₂–CH₄–illite systems. Conclusions Quartz and illite have higher CO₂ adsorption capacity, greater CH₄ displacement capacity, and better CO₂ storage effect.

• Discussion on the element composition characteristics and material sources of Quaternary sedimentary facies based on the land quality survey results in Xiong’an New Area

  ZHOU Yalong, GUO Zhijuan, WANG Qiaolin, LIU Fei, WANG Chengwen, SONG Yuntao

  2025,52(2):714-726, DOI: 10.12029/gc20210423003

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  This paper is the result of environmental geological survey engineering. Objective This paper aims to investigate the distribution characteristics, the contents and distribution of soil elements in different sedimentary facies of Quaternary, the control factors and the sources of sediment materials in Xiong’an New Area, and to provide geochemical bases for the study of regional palaeogeographic evolution and epigenetic geochemical environments. Methods Based on the surface element content data obtained from the geochemical survey and monitoring of land quality in Xiong’an New Area, this study employs multivariate statistical methods (such as elemental content analysis and ratio tracing) to reveal the relationship between regional elemental geochemical distribution patterns and the epigenetic environment. Results The soil in the alluvial–lacustrine plain subregion has the characteristics of low value of SiO₂ and Na₂O, and high value of Al₂O₃, Fe₂O₃, MgO, CaO, K₂O and Na/Rb. The soil in the alluvial–diluvial plain subregion is characterized by high SiO₂ and Na₂O, and low Al₂O₃, Fe₂O₃ and Ca/Ba. The distribution of soil geochemical major elements is primarily controlled by chemical weathering intensity of source sediments, while epigenetic environment also influences the depletion and enrichment of major elements. The source area is currently in the stage of moderate chemical weathering dominated by plagioclase weathering, with no evidence of potassium metasomatism in weathering products. The soil parent materials in each sedimentary facies are mainly derived from the mature continental quartz source of Taihang uplift on the west side of Xiong’an New Area. Additionally, in the subregion of alluvial plain, parent materials of a small proportion of samples are from mafic volcanic and neutral igneous rocks. Conclusions Geochemical indicators such as soil element contents, element ratios and element combinations (Rb–U–Ga, Fe–Mg–Ni–V) can effectively differentiate sedimentary facies environments in the study area and serve as reliable tracers for soil parent material properties.

• Distribution characteristics and ecological, environmental and biological health effects of lithium in different geological environments

  YU Yang, WANG Denghong, WANG Wei, GAO Juanqin, WANG Chenghui, YU Feng, LIU Shanbao, KAN Lei, CEN Kuang, QIN Yan

  2025,52(2):727-744, DOI: 10.12029/gc20230316002

  Abstract: (1) HTML (0) PDF (809.28 KKB)(1)

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  This paper is the result of environmental geological survey engineering. Objective The new pattern of harmonious coexistence between humans and nature is influencing the research concept of geological ecological organic systems. Understanding and mastering the distribution characteristics of lithium in different geological environments can help improve the utilization efficiency of lithium resources and promote green transformation of development methods. Methods Focusing on the needs of geological work, this study analyzed the distribution characteristics, ecological, environmental, and biological health effects of lithium in different geological environments through extensive surveys, field sampling, physical and chemical property testing analysis using interdisciplinary research methods. Results The regional and multi–field coupling distribution characteristics of lithium in various spheres (hydrosphere: ocean floor, groundwater, rivers, lakes, glacier meltwater, snow water and rain; lithosphere: Continental crusts, rocks and soil; atmosphere and biosphere) were clarified. The spatial–temporal distribution characteristics and regional differences of lithium were analyzed. The influencing factors for complex biological, geological, geochemical processes as well as spatial–temporal patterns for each layer's large amount but complicated elements were preliminarily summarized. The distribution features for key layers with respect to land biosphere was enriched while a comprehensive evaluation index system was improved for large–scale lithium resource bases. A systematic quantitative evaluation model was established to assess changes in lithium concentration on surface water, groundwater, and soil caused under human activities (mining), revealing unique ecological and environmental effects associated with "key layers" along with both lack or excess health effects from lithium. Conclusions Research on the distribution characteristics and ecological and environmental effects of lithium in different geological environments shows that pegmatite–type lithium resource development has overall safety control over its impact on ecology and environment while there are still some critical issues that need to be resolved regarding clean efficient development and utilization for clay–type and brine–type Lithium resources. With further deepening research into theoretical problems related to lithogenic mechanisms coupled with interdisciplinary basic research applications and simulation technology will make breakthrough progress possible towards understanding migration and transformation mechanisms associated with Lithium elements. While physiological amounts are beneficial to health excessive levels within organisms can cause certain side–effects even toxic reactions so it is necessary to continue conducting systematic studies on eco–environmental and biological health effects across different types and sources of Lithium resources providing theoretical basis support towards safe rational development strategies concerning strategic emerging minerals along with promoting eco–civilization construction efforts within China.

• Distribution of suspended sediments and action of nearshore currents in Xiangyun Island, Laoting County, Hebei Province

  WEN Mingzheng, TIAN Lizhu, ZHANG Shaotong, YANG Peng, LI Yong, WANG Fu, WANG Zhenhao

  2025,52(2):745-755, DOI: 10.12029/gc20210326006

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  This paper is the result of marine geological survey engineering. Objective There are high–quality natural fine sand distributed along the coast of Xiangyun Island in Hebei, which is a famous coastal tourist island. Simultaneous investigation and research on the concentration of suspended sediments and nearshore current in this area is of great significance to the ecological environment of Xiangyun Island and its nearshore engineering. Methods The current velocity and flow direction of the sea area were continuously profiled by ship–borne Acoustic Doppler Current Profiler (ADCP), and the distribution of suspended sediments in the sea area was qualitatively discussed according to the backscatter intensity recorded by the instrument. Results (1) The current in Xiangyun bay is mainly parallel to the coastline, which has obvious reciprocation. The magnitude of flood current was obviously larger than ebb current, the flood current was gradually weakened along the shore direction, however the ebb current in the southwest of Xiangyun bay increased along the shore direction; (2) During the transition from flat tide to ebb tide in Xiangyun Island sea area, the current turning starts from the bottom water, and the current turning and tide level change have certain lag; (3) The data of backscatter intensity shows that: there was a high concentration layer in Xiangyun bay coastal area, and the concentration increases along the shore direction, and the concentration of suspended sediment gradually decreases from northeast to southwest. Conclusions Xiangyun Island coastal waters under the action of the tidal current, suspended sediment along Xiangyun Island shoreline from northeast to southwest, is the main reason for the Xiangyun Island in the northeast section erosion and the southwest section deposition.

短文（发现与进展）

• Discovery of Baiyinchang type’s marine volcanic copper polymetallic deposit (174.9 kt) in the Beishan area, Gansu

  WANG Xueyin, YANG Yongchun, WANG Ganggang, FAN Xinxiang, DAI Shuang, ZHANG Xu, SONG Xiaohong, WANG Zuogang

  2025,52(2):756-757, DOI: 10.12029/gc20240805001

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• Discovery of a new porphyry–type beryllium deposits (359 t) in Hongjianbing Mountain of Beishan area, Gansu

  LIU Shengjiang, XU Lei, ZHANG Wei, ZHAO Jianguo, TANG Wenyi

  2025,52(2):758-759, DOI: 10.12029/gc20240320001

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• Discovery of a new medium–sized gold deposit in Beishan, Gansu Province: 703 East Gold Mine (5.2 t)

  REN Xiaodong, ZHI Chao, CHEN Shengmin, CHEN Zhenhai, CAO Heng, LU Guangrong, CUI Yong

  2025,52(2):760-761, DOI: 10.12029/gc20240716002

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• Discovery of a large fluorite deposit (1000 kt) in Baolaihuduge, Beishan orogenic belt, Gansu

  WANG Ganggang, LI Yupeng, YANG Yongchun, FAN Xinxiang, CHEN Yongyao

  2025,52(2):762-763, DOI: 10.12029/gc20241111002

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• Discovery of hydrothermal vein–type gold deposit (1.2 t) in Pulang porphyry copper deposit, northwestern Yunnan

  ZHANG Chuanyu, SU Xiaoyu, LUO Jianhong, YU Haijun, ZHU Yuezhang, XU Chongyang

  2025,52(2):764-765, DOI: 10.12029/gc20240710002

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New and Highlights

• Research on the development trend of geology from the perspective of bibliometrics: A case study of NSFC General Program concluded in recent 10 years

  CHEN Yang, SONG Weijian, WANG Xin, WANG Xiaoli

  2025,52(2):766-772, DOI: 10.12029/gc20241114001

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• Genesis, distribution, deposit types, development and utilization status and prospecting prospect of peridotite in China

  ningpengyuan, WANG chunlian, Zhu pinging, Liang zhen, Yan kai, Liu dianhe

  DOI: 10.12029/gc20230904002

  Abstract: (490) HTML (0) PDF (1.79 MKB)(1710)

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  Abstract: [Objective] Peridotite is an important mineral resource in China, which is widely used in building materials, refractory materials and fertilizer raw materials. Studying the origin, distribution and prospecting prospect of peridotite ore deposit is an effective way to solve the shortage of olivine resources in our country, and it is an important guideline for discussing the origin and prospecting direction of chromite ore deposit. [Methods] This paper summarizes the origin,distribution, mineral deposit types, development and utilization of peridotite in China by collecting and sorting out previous research data. [Results] According to the output of olivine, peridotite includes two main types of deposit: peridotite envelope type occurring in basalt and vein filling hydrothermal type occurring in peridotite. The main mineral areas of peridotite in China are Nanyang in Henan Province, Hebei Province, Jiaohe in Jilin Province and Shangnan in Shaanxi Province. Jiaohe olivine gem deposit in Jilin is the main source of olivine gem in China. The calc-magnesium-olivine deposit in Shangluo Mountain area at the border of Henan Province and Shaanxi Province has reserves of about 500 million tons with a grade of 44%. [Conclusions] The known resources of peridotite in China are not very rich, but the ore quality is good. As of 2022, China's Ministry of Natural Resources statistics, the national reserves of 16008 million tons, the total amount of peridotite ores for fertilizer in the country is 2,492,200 tons, and the total amount of peridotite ores for refractory in the country is 17,766,100 tons. The olivine gem deposit in Jilin Jiaohe and Wanquan County of Hebei Province is an important olivine gem deposit because the olivine gem mine in Hebei Province has been closed. At the same time, the partial melting of peridotite is closely related to the enrichment of chromium, and the liquid phase immiscibility of the melt formed by partial melting of the depleted mantle leads to the formation of silicate magma and chromium-rich pulp. The study of peridotite is of great significance not only for the exploration of peridotite deposits, but also for the deposits with peridotite as the surrounding rock.

• The cuticular features of the Phoenicopsis fossil leaves and its response to the hot-humid climate during the Middle Jurassic in Yanchi area, Ordos Basin

  Feng Yongtai, Wei Yi, Yang Bing, Zhang Xinzhi, Lei Xiaoting, Ma Yanting, Huang Zhuo, Wang Tao, Tan Ning

  DOI: 10.12029/gc20230827001

  Abstract: (171) HTML (0) PDF (1.26 MKB)(796)

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  [Methods]Plant fossils are the best materials to record terrestrial climate change in geological history, especially to the change of the paleo-CO2 concentration. Phoenicopsis (Windwardia) cf. rudinervis was identified due to the study of the morphology of the fossils collected from the Jurassic Yan ''an Formation in well Ningdong 2, Yanchi area, Ordos Basin. [Objective]In order to reconstruct the paleo‐atmospheric CO2 concentration, paleo‐temperature and water use efficiency of plants during the Middle Jurassic, leaf fossils of Phoenicopsis (Windwardia) cf. rudinervis were selected from horizon for calculating the the epidermal stomatal parameters and their isotope carbon composition of leaf cuticles. [Results]The results show that the average stomatal index (SI) of Phoenicopsis (Windwardia) cf. rudinervis is 4.25%, The paleo‐atmospheric CO2 concentration obtained by the stomatal ratio method is 1599 ppm. The paleo‐average temperature of Yanchi is about 1.2℃~31.4℃. The average value of the stable carbon isotope δ13C of plant fossils is -23.6‰, and its water use efficiency (WUE) is calculated to be 348.2 mmol/mol. [Conclusions] In general, the Middle Jurassic of Yanchi area in Ordos Basin belongs to a warm temperate - subtropical humid climate which reflected by the high CO2 concentration. Compared with previous data, we speculate that the paleo-CO2 concentration of the Middle Jurassic in northern China was significantly higher than that of the Early Jurassic, which may be related to the large-scale volcanic activities of the Yanshan Movement.

• Formation characteristics of hot springs and its development prospects in mountain areas around the capital of China

  LIU Weipeng, JIA Xiaofeng, ZHANG Zichun, ZHANG Qiuxia, YANG Li, LI Shengtao

  DOI: 10.12029/gc20230708001

  Abstract: (161) HTML (0) PDF (977.40 KKB)(1144)

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  Abstract: The paper is the result of geothermal geology survey engineering. [Objective]The mountainous areas surrounding the capital city belong to the ecological conservation area of Beijing-Tianjin-Hebei, including the contiguous areas of extreme poverty, and are rich in hot spring resources, but the degree of exploration and development is low. It is of certain guiding significance to carry out research on the distribution pattern and development characteristics of hot springs for the exploration and development of geothermal resources in mountainous areas. [Methods]In this paper, based on the collection of information on hot springs and deep tectonics in the mountainous areas of Beijing, Tianjin and Hebei, superimposed analysis reveals the connection between hot spring distribution and deep tectonic thermal background, and explores in depth the hot spring heat source and its formation. Combined with supplementary surveys, sample collection and comprehensive research, the development characteristics of hot springs were summarized, and prospects for hot spring development and utilization in the study area were proposed according to local conditions. [Results]The results show that hot springs are mainly distributed along NE and EW deep major fractures in the form of bands or beads, 90% of the hot springs are distributed within the deep structural variation zone of the Moho surface in the study area. The temperature of hot springs has a certain negative correlation with the depth of dwelling, the depth of dwelling in the high hot spring area in the northern Yanshan being about 20km, the depth of dwelling in the relatively high hot spring area in the Yanshan-Taihang Mountains junction zone being about 22～24 km and the depth of dwelling in the low hot spring area in the southeast Yanshan being 22～26 km; the heat source of hot springs mainly comes from the mantle heat or "low-velocity-high-conductivity layer", and the upper mantle diapirs and deep large faults provide good channels for the upwelling of deep heat sources; On the regional scale, there is no direct correspondence between the hot spring outcrop temperature and the depth of circulation, and the thermal reservoir temperature of sedimentary rock reservoirs in the intermountain basin is low, with a large flow rate of hot springs, up to about 120 m3/h. The thermal reservoir temperature of metamorphic rocks is generally greater than 100℃, with a smaller flow rate. The hot spring water in the study area generally has medical development and utilization value, among which, the northern Yanshan and intermountain basins, have a better potential for space heating, and areas such as Qijia-Maojingba can be further developed in the direction of thermol-electric integration. [Conclusions]The distribution and development characteristics of hot springs in the mountains area around the capital city are influenced by the deep tectonic and regional geological structure. The northern Yanshan Mountains and intermountain basins have good development and utilization prospects.

• Research status and prospect of regional landslide assessment integrating slope deformation characteristics in the complex mountainous area

  Yang Zhihua, WU Ruian, GUO Changbao, SHAO Weiwei, Wu Yuming, YU Pengfei

  DOI: 10.12029/gc20230630002

  Abstract: (149) HTML (0) PDF (1.02 MKB)(1239)

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  [Objective] The slope deformation is common in the mountainous areas, which significantly promotes landslide development and increases landslide risk. So, it is the important factor for the regional landslide assessment. [Methods] By reviewing literatures, the research status of regional landslide assessment integrating slope deformation characteristics were summarized. [Results] The relevant theoretical models and technical methods are not mature and are still in the stage of preliminary research. The temporal resolution of regional slope deformation should be further improved, and key characteristics of the long time series slope deformation should be captured, and the spatio-temporal distribution of regional slope deformation should be deeply analyzed. A preliminary regional landslide assessment system integrating slope deformation was constructed, including process steps, technical methods and factor indicators. The main technical methods include the qualitative judgment based on expert experience, weighted layer overlay based on expert experience and correction matrix, slope deformation as a factor index of regional landslide assessment, slope deformation as a landslide sample of regional landslide assessment. The slope deformation factor can be further divided into slope deformation type, intensity, distribution position and time change. [Conclusions] It is necessary to combine new technologies such as machine learning and artificial intelligence to propose or optimize the new quantitative regional landslide assessment models that integrate the slope deformation characteristics to improve regional landslide assessment accuracy. It is expected to promote the study on regional landslide assessment integrating slope deformation, and support the early landslide prevention in the complex mountainous areas.

• Characteristics and health risk evaluation of soil heavy metals in Longshan County, Hunan Province

  XU Qingyang, Dai Liangliang, PENG Zhigang, ZHANG Jun, XIAO Kaiqi, GONG Hao, WU Huanhuan

  DOI: 10.12029/gc20230703001

  Abstract: (306) HTML (0) PDF (1.33 MKB)(750)

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  Abstract: This paper is the result of geological survey engineering. [Objective] A total of 775 soil samples were collected in Longshan County for the purpose of analyzing the content characteristics of soil heavy metals, including As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. Additionally, an evaluation of the health risks caused by soil heavy metals was conducted. [Methods] To assess the level of soil heavy metal pollution, the geo-accumulation index was utilized. The source of soil heavy metals was identified through correlation analysis and principal component analysis. Furthermore, a health risk model was employed to assess the potential risks imposed by soil heavy metals on human health. [Results]The results of the analysis revealed that the average concentration of Cd in the soil of Longshan County was significantly higher than the background value observed in the soil of Hunan Province. This suggests that there is a certain degree of Cd enrichment in the soils of Longshan County. Moreover, the coefficients of variation for Hg, As, and Cd were greater than 0.5, and the coefficient of variation for Hg exceeded 1, indicating that these heavy metals may be influenced by human activities. The presence of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn contamination was observed in the soils of Longshan County. Notably, Cd pollution was widespread, and some areas exhibited severe levels of Hg contamination. The sources of soil heavy metals in Longshan County can be categorized into three groups: Cr, Cu, and Ni primarily originate from the soil parent materials, while As, Cd, Pb, and Zn are predominantly influenced by lead-zinc mining and smelting activities. The source of Cd also has some association with the soil parent materials. Furthermore, Hg is mainly derived from the combustion of fossil fuels. The health risks caused by soil heavy metals were found to be higher for children compared to adults. Additionally, special attention should be given to the health risks caused by soil heavy metals in Liye Town, Miaoertan Town, and Luota Town of Longshan County. Furthermore, non-carcinogenic risks are primarily attributed to As and Cr, whereas carcinogenic risks are primarily linked to Cr and Ni. Oral ingestion was identified as the main exposure route contributing to health risks. [Conclusions] There was a variable degree of heavy metal pollution in the soil of Longshan County, and As, Cr, Ni were the main contributing factors to health risks.

• Characterization the hydrogeochemical spatial distribution of the contaminated groundwater based on groundwater multilevel sampling technology – the case of a landfill site in Hubei

  LIU Xuehao, Zou Jin, Yi Chenyun, Wang Ping, Wang Lei, Li Jiangshan, Long Sijie, Huang Changsheng

  DOI: 10.12029/gc20230209001

  Abstract: (495) HTML (0) PDF (1.02 MKB)(1179)

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  [Objective] The leakage of leachate from a landfill can cause severe groundwater contaminations. Characterization the spatial distribution of the landfill-derived contamination plume is crucial for site remediation and pollution investigation. [Methods] In this paper, a typical case of groundwater pollution investigation at a landfill in Hubei is combined with the implementation of a six-layer groundwater multilevel sampling well (-6 m、-8 m、-10 m、-12 m、-16 m、-20 m), and 14 sets of groundwater chemical samples as well as other hydrogeological survey data to reveal the hydrogeochemical spatial distribution of the contaminated groundwater. [Results] The results indicate that the concentrations of most ions in groundwater such as TDS, COD (Mn), Mg2+, HCO3- and Cl- decrease linearly with increasing vertical depth, thus indicating that surface rainfall infiltration and anthropogenic pollution are the controlling influences on the shallow groundwater. The concentration of NH4+, NO3-, NO2-, Mn, Ni and other ions increases linearly with increasing vertical depth, reflecting groundwater chemical field under the control of natural geological condition and water-rock interaction. In addition, the correlation coefficient matrix analysis characterises the stratified distribution of groundwater chemical components, the correlation coefficient between the groundwater sample from the U-tube groundwater multilevel sampling well and other conventional shallow boreholes decreases from 0.984 to 0.566.[Conclusions]The conclusion indicates that the novel groundwater multilevel sampling technology has the ability, to characterize the hydrogeochemical spatial distribution of groundwater along the vertical depth of the geological layers, to differentiate and reveal the impacts of natural geological factors and human-made pollution, thus to identify the spatial distribution of groundwater plumes. In a word, the groundwater multilevel sampling technology could provide quantities’ data and accurate guidance for site-scale groundwater pollution remediation and risk management.

• Metallogenic conditions and prospecting direction of sandstone-type uranium deposit of Sifangtai Formation in Qian''an area, Songliao Basin

  XING Zuochang, JIA Licheng, WANG Xiujie, LUO Min, ZHANG Hang, ZHANG Yunlong, LIN Xiaobin

  DOI: 10.12029/gc20230412001

  Abstract: (127) HTML (0) PDF (2.61 MKB)(1336)

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  Abstract: This paper is the result of mineral exploration engineering. [Objective] The study of uranium metallogenic conditions of Sifangtai Formation in the hinterland of Songliao basin is relatively weak. [Methods] Through comprehensive analysis of core, logging, seismic, trace and other data, the tectonics, stratigraphy and transformation of Sifangtai Formation in Qian’an area has been sorted and it is the first time to systematically summarize the uranium metallogenic elements of sandstone-type uranium deposits in the the hinterland of Songliao Basin. [Results]It shows that Sifangtai Formation in Qian''an area has favorable metallogenic conditions such as structural window, deep and large faults, braided river delta channel sand belts, good uranium source conditions and epigenetic transformation. It is considered that Sifangtai formation has both infiltration and exudative uranium metallogenic conditions, and exudative metallogeny is dominant. Based on these facts, the exudation-infiltration coupling Uranium metallogenic model of Sifangtai Formation in Qian''an area, Centrel Songliao Basin, has been constructed. Finally，it is proposed that the braided river to braided river plain channel sand in Rangzhi-Chaganhua Town has great uranium metallogenic potential, which as been predicted to be the most favorable object for further exploration. [Conclusions]This study is the first to introduce exudative metallogeny into the systematic evaluation of uranium mineralization conditions in Sifangtai Formations of the Songliao Basin, changing the previous single approach of evaluating the target layer from the perspective of infiltration metallogeny. It can effectively expand the exploration thinking of the red variegated formations in the hinterland of the basin, thereby greatly expanding the prospecting range in the Songliao Basin.

• Relationship between Indosinian magmatic activity and Li-Be-rare metal mineralization in the eastern section of West Kunlun and its implications for prospecting

  Gao Jinggang, liangting, Fengyonggang, Tanxijuan, Lyanrong, Liyong, Zhaoruyi, Zhoubin

  DOI: 10.12029/gc20230314001

  Abstract: (172) HTML (0) PDF (1.43 MKB)(1534)

  Abstract:

  Abstract: This paper is the result of mineral exploration engineering. [Objective] The aim of this paper is to investigate the relationship of Li-Be-rare metal mineralization and Indosinian magmatism in the eastern part of the West Kunlun Orogenic Belt through a comprehensive study of Indosinian magmatic activities, granite chronology, and geochemical characterization. Furthermore, the corresponding metallogenic regularity is summarized, and the exploration prospecting of rare metal pegmatite deposits is given. [Methods] Based on the our recent research, the geological details in the eastern part of the West Kunlun Orogenic Belt, including ages, mineral assemblages, geochemical characteristics, isotopic characteristics (Hf, Nd and Li, etc.) of the Indosinian magmas, are summarized and fully compared for the first time. The genetic link between the pegmatite-hosted Li-Be-rare metal mineralization and Indosinian magmatism is investigated. [Results] The large composite granite pluton formed in Indosinian period in the eastern part of the West Kunlun Orogenic Belt is mainly composed of quartz diorite, biotite monzogranite and two-mica monzogranite (including garnet tourmaline two-mica monzogranite), which was formed due to partial melting of the crust in a post-collision regime. The reliable chronological data show that there is no age difference between the composite granite (216.7~208.8Ma) and the granitic pegmatites (211.9~208.1Ma), suggesting that they were formed at the same time. The characteristics of minerals (garnet, tourmaline) and Li isotopes indicate that the two-mica monzogranite (garnet tourmaline two-mica monzogranite), garnet-bearing tourmaline muscovite granite pegmatite and spodumene-albite pegmatite were likely derived from the same magma source. [Conclusions] Results show that two-mica monzogranite and in particular garnet, tourmaline-bearing two-mica monzogranite exhibit close relationship with the pegmatite-type rare metal deposits. The peripheries of Aktas and the 509 Daoban-Quanshuigou area are favorable section for prospecting lithium-rich pegmatite.

• Breakthrough and revelation of ultra-shallow shale gas exploration in complex structural area of northern Guizhou: Taking Well RX1 as an example

  Lin Ruiqin, Wang Yisong, Shi Fulun, Liu Dadong, Zhang Daquan, Feng Xia, Zhou Zhe, Chen Yi, Zhao Fuping, Zhang Ziya, Du Wei

  DOI: 10.12029/gc20230317002

  Abstract: (171) HTML (0) PDF (1.50 MKB)(1464)

  Abstract:

  [Objective] By analyzing the organic geochemistry, physical properties, and pore characteristics of the Wufeng-Longmaxi Formation in well RX1, the basic geological conditions of the Fuyan yansynclinal shale gas accumulation are clarified, and the exploration and development potential of ultra-shallow shale gas in the complex structural area outside the basin is discussed. [Methods] This study utilizes the core of Well RX1 in northern Guizhou to conduct comprehensive experimental analysis such as on-site desorption, geochemical testing, on-site fracturing effect, and reservoir characteristics. In combination with exploration data from neighboring areas, it explores the impact of burial depth and the structural preservation environment on the enrichment of ultra-shallow shale gas in northern Guizhou. [Results] The results show that the thickness of the high-quality hydrocarbon source rock section in the Wufeng-Longmaxi Formation of the RX1 well is 14.78m, the average content of total organic carbon is 4.43%, the maturity of organic matter is between 2.36% and 2.78%, and the kerogen type is II1, which has a good hydrocarbon generation basis; the average porosity of high-quality shale is 3.30%; and the content of brittle minerals is high, with an average brittleness index of 69, which provides a good reservoir space for shale gas. [Conclusions] The successful exploration practice of well RX1 confirms that shale gas can be enriched in the synclinal structural unit with a depth less than 1000m in the target layer of the complex structure area outside the Sichuan basin, which has good potential for construction and production and can be used as a favorable exploration target in the next step. Based on the analysis of regional geological data, it is believed that the compression-torsional structural system formed by the superposition and transformation of Cenozoic structures is an important place for shale gas accumulation in complex structural areas outside the basin. The reservoir-controlling effect of the compression-torsional structural system should be the focus of the next round of exploration and research.

• Geological setting, spatiotemporal distribution of predominant metal deposits in eastern section of China, Mongolia and Russia

  LIU Jinlong, Li Zhumin, ZHOU Yongheng, Dong Cunjie, Chen Liangxi

  DOI: 10.12029/gc20230215001

  Abstract: (145) HTML (0) PDF (3.19 MKB)(2176)

  Abstract:

  [Objective] The eastern section of China, Mongolia and Russia has a complex geological evolution history and strong mineralization. Strengthening the study of cross-border regional mineralization, especially the summary of region-wide mineralization regularity, is of great significance for improving the level of regional basic geological research and prospecting and exploration. [Methods] By collecting various geological datas, the metallogenic geological characteristics, resource endowment, temporal and spatial distribution of deposits, metallogenic background and so on are sorted out. [Results] In the study area, 10 super-large deposits, 33 large deposits, 55 medium deposits and numerous small deposits (and occurrences) have been proved or discovered. Generally, they can be divided into the deposits related to the Precambrian tectonic system, the deposits related to the Paleo-Asian Ocean tectonic system, the deposits related to the Mongolia-Okhotsk tectonic system, and the deposits related to the superposition Mongolia-Okhotsk tectonic system and the Paleo-Pacific tectonic system. [Conclusions] The spatial and temporal rules of regional deposits are obvious. The most important deposits formed in various historical periods include: Archean Fe deposits distribute in the West Aldan -Sutam area; The Paleoproterozoic Cu, Fe, Ti deposits distribute in the Udokan-DyosLeglier area and the Neoproterozoic Pb, Zn deposits distribute in the Baikal–Muya tectonic zone; The Cambrian-Silurian Fe, Zn, Ti deposits distribute in the Yenisey-Transbaikalian tectonic belt; The Carboniferous Au deposits distribute in the Baikal-Patom tectonic zone; The Triassic Cu and Mo deposits in the Orhon-Selenge region and the Late Permian-Early Triassic Fe deposits in the Angara-Ilim region; The Middle Jurassic to Cretaceous Au, Pb, Zn, W, Mo deposits distribute in the Mongolia-Okhotsk tectonic belt and its surrounding areas.

• Migration enrichment and health risk assessment of oasis soil fluorine in typical arid areas

  liujingyu, heyingfeng, gengjianyang, huhongli, DUGUER Weiwei, zhangyi, chenzhichao

  DOI: 10.12029/gc20230417001

  Abstract: (124) HTML (0) PDF (1.68 MKB)(1557)

  Abstract:

  【Objective】To accurately analyze the migration enrichment pattern of soil fluoride in the arid oasis area and the risks to human health. 【Methods】Combining statistical theory and spatial analysis tools to analyze the factors influencing soil fluoride transport enrichment and carry out soil fluoride health risk assessment.【Results】The results show that: (1) The mean fluoride content of the surface soil in the study area is 543 mg?kg-1, which is 1.28 times the background fluoride value for soils in the oasis zone and 1.14 times the national background fluoride value for soils in layer A. (2) The vertical variation of soil fluoride content in the study area is influenced by soil texture, organic carbon content, and other soil physicochemical properties; the horizontal distribution of soil fluoride content is influenced by soil pH, strong evaporation climate, etc., and shows a clear "Surface Riches". At the same time, the fluoride content of the soils in the area was significantly and positively correlated with Fe2O3 and MgO, with Al2O3, K2O, and CaO, and negatively correlated with SiO2 and Na2O, the ''signature'' indicators of the landscape environment. (3) The sensitivity analysis showed that body weight contributed -49.5% and -50.9% to the non-cancer risk in adults and child, respectively, indicating that the lower the body weight, the higher the non-cancer risk, which was more pronounced in children.【Conclusions】The main source of soil fluorine in the study area is the soil-forming parent material, and the "sand source" of the Tarim Basin is the main source of fluorine. At the same time, exogenous inputs such as anthropogenic factors also influence the spatial distribution pattern of soil fluorine. The spatial distribution pattern of soil The main route of exposure to soil fluorine in the study area is oral ingestion, which is more pronounced in children, but the overall risk is low.

• Depositional environment since Late Pleistocene (113.96 ka) in the northwestern Bohai Bay and its indications to transgression and tectogenesis

  ZHANG Xiaofei, ZHANG Xuebin, ZHANG Yongyi, Niu Shuyin, Sun Aiqun, WANG Yongli, FAN Hangyu, LI Mingchen, HAN Rongwen

  DOI: 10.12029/gc20221207001

  Abstract: (150) HTML (0) PDF (2.05 MKB)(1420)

  Abstract:

  Abstract: This paper is the result of maring geological survey engineering. [Objective] The northwest of Bohai Bay is an area where the depositional environment changes frequently in North China Plain and is also the main depressed area of the neotectonics. Strengthening the stratigraphic research since Late Pleistocene in Northwestern Bohai Bay and analyzing the evolution process of the depositional environment is of great significance to the study of sea-level change and subsidence of coastal areas.[Method]Based on the three full coring boreholes QLT03, QEJ01 and NHG14 in the northwest coast of Bohai Bay, and by integrating the lithostratigraphic and biostratigraphic methods, AMS14C and optical stimulated luminescence dating are used to compare and analyze the collection boreholes in the adjacent area, discussing the depositional environment and its indications to transgression and tectogenesissince late Quaternary in the study area.[Result]The results show that early Late Pleistocene of the study area is the development period of delta plain and fluvio-lacustrine facies, the middle is the development period of floodplain-lacustrine facies and delta plain, the late is the development period of meandering stream- floodplain facies, and Holocene is the development period of delta plain- flood plain. The study area develops three phases of transgressive strata from bottom to top, namely, the third transgressive layer in early Late Pleistocene, the second transgressive layer in late Late Pleistocene and the first transgressive layer in Holocene. The scale of transgression has gradually strengthened from the ancient to the present. The transgressive layers in each phase are more consistent with the global sea level change and have good correspondence with the high sea level in MIS5, MIS3 and MIS1 phases from bottom to top. There has been differential subsidence movement in the study area since Late Pleistocene, and the differential movement has slowed down in Holocene.[Conclusion] Under the background of continuous tectonic subsidence, large-scale marine transgressions in the coastal area of Bohai Bay have all occurred since Late Pleistocene. These transgressions are related to the long-term subsidence process in the southeastern area of Tianjin along the coast of Bohai Bay, and the subsidence center moved from Bamencheng Town of Baodi District to Chadian Town of Hangu District. After entering Holocene, the tectonic activity weakened and the differential subsidence movement was not obvious. The late Quaternary stratigraphic development and depositional environment evolution in the coastal areas of Bohai Bay are controlled by sea level changes.

• Distribution of Quaternary sedimentary thickness in South China Sea and its main controlling factors

  LI Xuejie, SUN Meijing, CHEN Jiale, GAO Hongfang, PENG Xuechao

  DOI: 10.12029/gc20220930001

  Abstract: (169) HTML (0) PDF (2.22 MKB)(1357)

  Abstract:

  Abstract：This paper is the result of 1:1,000,000 marine geological survey engineering. [Objective] Quaternary sedimentary thickness can not only reflect the provenance and sedimentary characteristics, but also reflect the tectonic activity characteristics to a certain extent. [Methods] Based on a large number of single channel and multi-channel seismic data and verified by drilling holes, the Quaternary thickness map of the SCS was compiled. [Results] The thickness of quaternary sediments in the South China Sea (SCS) varies a lot, with the maximum thickness over 2000m and the minimum one close to 0. [Conclusions]Sedimentary and subsidence centers were formed in the western margin of SCS, including Yinggehai, Zhongjiannan and Wan''an sea area, which indicates that the fault zone in the western margin is still active in Quaternary period and controls the development of these subsidence centers. The development of NE trending sedimentary centers on the northwest continental slope of the South China Sea may indicate that the northwestern SCS is still dominated by extension in quaternary. The thickness of quaternary in Dongsha sea area is near 0, indicating that the area has been continuously uplifted and washed by strong current since quaternary. Therefore, the northern South China Sea shows a pattern of subsidence in thewest and uplift in the east. The relatively thicker Quaternary in the Manila Trench in the eastern margin of the SCS is mainly a result of tectonic compression resulting in sedimentary layers thicker and abundant provenance from Taiwan and the Philippines.

• Late Triassic paleogeographic inversion and its control on source rocks in the Qiangtang Basin，Xizang (Tibet)

  fuxiugen, chenminghao, wangjian, weihengye, zengshengqiang, wangzhongwei, shenlijun, zhougang

  DOI: 10.12029/gc20230307001

  Abstract: (156) HTML (0) PDF (1.93 MKB)(1477)

  Abstract:

  This paper is the result of petroleum geological survey engineering. [Objective] Effect and significance of various tectonic history on the development characteristics and spatial distribution of source rocks in the Qiangtang Basin during the Triassic-Jurassic. [Methods] In the present study, we discuss the sedimentary records of the Late Triassic tectonic inversion. [Results] The Middle Triassic sequence has typically shallowing-upward changes and a marine regression related regional uplift. However, the Early Jurassic sequence displays typically deeping-upward changes due to the tectonic subsidence and transgression. We also identify paleogeographic inversion during the Late Triassic in the Qiangtang Basin. In the northern Qiangtang depression, the pre-existing (Middle-early Late Triassic) marine depositional areas turned into terrestrial units during the Norian. In contrast, the previously (Middle Triassic) terrestrial part of the sourthern Qiangtang depression became marine units. [Conclusions] Our study suggests that the distribution of source rocks in the Qiangtang Basin was mainly controlled by the sedimentary change and paleogeographic inversion during the Late Triassic. The Late Triassic source rocks were probably related to the foreland basin and developed in the deep water area of the northern Qiangtang depression, while the coal-bearing source rocks were developed around the basin. The Early Jurassic source rocks are probably related to the passive continental margin basin and developed in the deep-water area of southern Qiangtang depression. Oil shale-bearing source rocks are well developed in the lagoon in the northern part of Southern Qiangtang depression.

• Bioavailability and influencing factors of Zn and Cu beneficial elements in soil-crop system in typical farming areas of red layer intermountain basin in the southwest China

  XU Lei, ZHAO Mengsheng, CHEN Weizhi, BA Yong, ZHANG Ya, HOU Qingye, LU Fangfang, QIAN Kun

  DOI: 10.12029/gc20230216002

  Abstract: (179) HTML (0) PDF (1.12 MKB)(1469)

  Abstract:

  Abstract: This paper is the result of agricultural geological survey engineering. [Objective] A land quality geochemical survey carried out in Chuxiong area of central Yunnan Province had found a large area of zinc and copper-rich soil. The purpose of this study is to study the migration and transformation mechanism of Zn, Cu and other beneficial elements in the soil-crop system in the farming area of zinc and copper-rich red bed mountain basin in southwest China. [Methods] In this paper, the typical farming area of Yao''an in central Yunnan is selected as the research area. Based on the geochemical data of surface soil and crop seed-root soil, the main control factors affecting the absorption and enrichment of Zn and Cu in rice and corn are discussed by analyzing the content characteristics of Zn and Cu in surface soil, crop seed and root soil, and the prediction model of crop Zn and Cu bioconcentration coefficient is established. [Results] The results showed that the average Zn and Cu contents in the surface soil of Yao ''an alluvial basin are 105.40 mg/kg and 42.67 mg/kg, the proportion of zinc-rich and copper-rich land (first-class) area are 84.86% and 90.59%, the average Zn and Cu contents in rice seeds are 19.28 mg/kg and 2.92 mg/kg, the enrichment rates are 100% and 70%, and the bioconcentration coefficients are 0.20 and 0.07, the average Zn and Cu contents in corn seeds are 21.42 mg/kg and 2.06 mg/kg, the enrichment rates are 80.00% and 6.70%, and the bioconcentration coefficients are 0.20 and 0.07. [Conclusions] There are differences in factors affecting Zn and Cu enrichment in rice and corn seeds. The main factors controlling Zn bioconcentration coefficients in rice are Soil-Zn, N, TFe2O3, and the main factors controlling Cu bioconcentration coefficients in rice are Soil-Cu, OM and S. The main factors controlling Zn bioconcentration coefficients in corn are Soil-Zn, SiO2/Al2O3 and TFe2O3. The multi-linear regression equation of Zn and Cu bioconcentration coefficients of rice and corn seeds in the typical farming area of the red layer mountain basin in Yunnan was established, and the optimal model decision coefficient was greater than 0.495, the prediction effect of rice is better than corn, and the prediction effect of Zn is better than Cu. The optimal model predicted that the planting area of Zn-rich rice, copper-rich rice and zn-rich corn in Yao''an County are 72.87 km2, 70.47 km2 and 69.71 km2. Therefore, the planting structure planning of rice and corn in the study area can be optimized to serve the development of plateau characteristic agriculture and the implementation of rural revitalization strategy.

• Correlation analysis of formation and ecological characteristics and application of environmental restoration-Based on the practice of Luoshan area in the western section of Dabie Mountains

  Li Xin, Dong Haogang, Xie Xiang, Luo Minxuan, Wu Feng, Yang Tao, Huang Jinyan

  DOI: 10.12029/gc20220918002

  Abstract: (149) HTML (0) PDF (1.96 MKB)(2188)

  Abstract:

  Abstract: This paper is the result of ecological geological survey. [Objective]Formation is the carrier of the geological environment. Studying the correlation between formation and ecological characteristics is helpful to correctly understand the causes of ecological problems and serve the precise restoration of the ecological environment. [Method] In this paper, Luoshan County, which has both low mountains, hills and plains, is selected as the research area. On the basis of combing the geological background and tectonic evolution characteristics of Luoshan County, 13 geological formation types are divided; Based on profile survey, data statistics, hydrological parameter test and other means, the geological characteristics of four typical geological formations were analyzed from the four aspects of rock, soil, hydrogeology and terrain slope, and the correlation between ecological characteristics and geological formations was discussed. Taking soil erosion as an example, the spatial distribution, cause analysis and restoration suggestions are carried out based on geological formation. [Results] The results show that, from the Cretaceous acid magmatic rock formation in the low mountain and hilly area to the Cretaceous continental pyroclastic rock-volcanic formation in the hilly area, the thickness of the parent material layer and soil layer has been increasing, and the content of gravel and sand has increased. Gradually less, the particle size of the soil becomes smaller, so the soil texture gradually changes from gravel soil (sandy loam), sandy loam, silty loam, and loam; the vegetation transitions from natural secondary forest to artificially planted economic forest, and the vegetation type changes from diversity It tends to be single, but the tree height and diameter at breast height are increasing; the correlation between geological formation and ecological characteristics is strong. The genetic analysis based on geological formations shows that soil erosion develops differently in different formations, among which the Cretaceous acidic magmatic rock formation is the most serious. The problem of soil erosion has a strong correlation with the terrain slope, mineral composition and grain size of rocks in different formations. [Conclusions] Using formation as a unit to analyze ecological characteristics has better pertinence and application prospects, and can more reflect the constraints of geology on ecology. The research results can provide a geological basis for accurate restoration of ecological protection and soil erosion in Luoshan County.

• Spatial distribution, origin, and health risk assessment of nitrate in groundwater of Cenozoic basalts in Zhangbei county, Hebei Province

  hejin, Ma Xuemei, Deng Qijun

  DOI: 10.12029/gc20220724001

  Abstract: (157) HTML (0) PDF (1.21 MKB)(1556)

  Abstract:

  【Objectives】In order to identify nitrate sources and health risks in groundwater of Cenozoic basaltic rock in Hebei province.【Methods】The basalt distribution region in Zhangbei county is selected as a typical study area. Based on hydrochemistry and isotopes data of 45 groups groundwater samples, the distribution characteristics and origin of nitrate in basalt groundwater were studied, the health risk of nitrate in groundwater was evaluated using the health risk assessment model .【Results】The results showed that the average concentration of nitrate in the groundwater of the study area was 86.08 mg?L-1, The nitrate concentration of 26.6% of the sampling sites exceeded the limit value of the III grade groundwater quality in GB/T 14848-2017《The Quality standard of Underground Water》 (20 mg?L-1);The nitrate pollution of different land use types varied greatly, and the content of nitrate in urban areas was the highest, followed by irrigated land,with forests、grasslands or dry land not exceeding the standard.The sources of nitrate in groundwater was mainly manure and domestic sewage, and the next was chemical fertilizer leaching;The health risks of nitrate exposure through skin contact among the population in the study area were at acceptable levels, while the health risk of nitrate intake from drinking water was higher, and the contribution rate of nitrate intake from drinking water accounted for 99.23% of the total risk, which was much higher than that from skin contact route.The health risks of drinking water intake and skin contact in children were significantly higher than those of adults.The health risks of groundwater nitrates to children in 75.55% of the sampling sites exceeded acceptable levels.【Conclusions】From the perspective of water supply safety, it is recommended to increase water purification equipment in high-risk areas to reduce human health risks

• Exploration and research progress of magmatic copper-nickel-cobalt sulfide deposits in the north-eastern margin of the Qinghai−Tibetan Plateau

  Liu Yuegao, Zhang Jiangwei, Feng Zhixing, Yang ShunLong, Wang Yizhong, Li Jiqing, Zhao Zhiyi, Wang Zhian, Li Shulei, Wang Houfang

  DOI: 10.12029/gc20230128003

  Abstract: (314) HTML (0) PDF (2.88 MKB)(1653)

  Abstract:

  [Objective] To improve the supply security of Cu-Ni-Co resources in China, it is necessary to sort out the mineralization regularity and prospecting indicators of the magmatic copper-nickel-cobalt sulfide deposit in the Phanerozoic in the Eastern Kunlun orogenic belt on the northern margin of the Qinghai-Tibet Plateau. [Methods]The geological, geochronology, geochemistry, and geophysical characteristics of five stages mafic?ultramafic complexes including the Late Ordovician?Early Silurian, the Middle Silurian?Middle Devonian, the Early Carboniferous, the Middle Permian?Early Triassic, and the Middle?Late Triassic are summarized. [Results] Based on the above work, the source area properties of magmatic copper?nickel deposits and their relationship with the highpressure?ultrahighpressure eclogite and the evolution of Proto?Paleo Tethys were discussed. The influence of crustal sulfur contamination and crystal differentiation on sulfide saturation was analyzed. The rules of the optimal location of copper-nickel ore bodies were summarized. The typical differences between the ore-forming mafic-ultramafic complexes and the no-ore mafic-ultramafic complexes were described. [Conclusions] At last, a comprehensive information exploration model was established.

• Characteristics and causes of acidic shallow groundwater in Gannan area in the upper reaches of Dongjiang River Basin ——Take Xunwu area as an example

  fuyu, donghaogang

  DOI: 10.12029/gc20220805004

  Abstract: (177) HTML (0) PDF (1.03 MKB)(1664)

  Abstract:

  [Objective]Gannan area in the upper reaches of Dongjiang River Basin is a typical water shortage area in China. The distribution of acid groundwater intensifies the lack of regional domestic water. [Methods]In this paper, Xunwu area in the upper reaches of the Dongjiang River basin is selected as the study area. Shallow groundwater is systematically collected, and the pH value, spatial distribution, hydrochemical types and action characteristics of acidic groundwater are analyzed by using hydrochemistry and mathematical statistics methods. From the point of view of material basis, circulation conditions and external factors, the causes of control of water rock action, aeration zone medium, acid rain, human action and other factors on acidic groundwater are discussed.[Results]The pH value of groundwater in the area is concentrated between 5.0 and 7.0; The spatial distribution has obvious correlation with geomorphic characteristics and circulation conditions: middle and low mountainsHCO3-Cl type (5.05)>SO4 type (4.8)>Cl type (4.5); Among the pH values of groundwater types in different media, pore fissure water of clastic rock > pore water of loose rock > fissure water of metamorphic rock >fissure water of magmatic rock.[Conclusions] The interaction between water and rock is the main role in the formation and evolution of pH value, and the dissociation of carbonic acid is the main material basis for the source of H+; Aerated zone medium and acid neutralization ability are the main water circulation conditions affecting the formation of acidic groundwater; Acid rain and human factors are external factors that cannot be ignored. The research results have a guiding role in understanding the origin of acidic groundwater, rational utilization and protection of groundwater resources in this area.

• Renewability of groundwater in Changzhou, Jiangsu Province: Based on isotopic technology

  SU Dong, GONG Xulong, YANG Lei, XU Shugang, ZHANG Yan, LYU Hang, BU Jianwei, GONG Yabing, GU Chunsheng

  DOI: 10.12029/gc20221019001

  Abstract: (108) HTML (0) PDF (1.17 MKB)(1559)

  Abstract:

  Abstract：This paper is the result of hydrogeological survey engineering. [Object] Changzhou is a typical industrialized city in the Yangtze River Delta. The regional groundwater there had experienced a periodic historical process of overdrafts and prohibitions of mining, resulting in a greatly change in the groundwater dynamic field. Thus, it is necessary to conduct a further study on the renewable capacity of the groundwater of Changzhou. [Methods] Based on the analysis of the existing hydrogeology conditions, the recharge, runoff and discharge conditions of groundwater and the characteristics of groundwater ages are systematically analyzed to evaluate the renewable capacity of groundwater using isotope technology. [Results] The results showed that, 18O and D of the shallow groundwater are more abundant than the deep groundwater due to the evaporation to a certain extent. The recharge time of the deep groundwater with relatively closed storage environment is earlier than that in the shallow groundwater. The shallow groundwater, basically affected by infiltration recharge of modern water, has an active circulation zone of modern water reached to a depth of 40m. As for the ages of the deep groundwater, it varies from less than 2000 to 25000 years, indicating that it is mainly composed of ancient water. [Conclusion] The renewal rate of the shallow groundwater is generally higher than 0.1%/a, and controlled by the storage conditions, surface water recharge and human activities, etc. Weakly, the renewal rate of the deep groundwater is generally less than 0.05%/a, and controlled by the distribution of river ancient channel, exploitation and utilization of human beings, etc. These results can provide scientific basis for protection and utilization the groundwater in Changzhou and other areas in the Yangtze River Delta.

• Evaluation of deep granitic geothermal resource potential based on discrete fracture network model：Taken as an example of the 3003.17m geothermal exploration well in Wendeng granite body in Shandong Province

  JIANG Haiyang, CAO Yanling, LIU Lian, KANG Fengxin, CUI Su, GUO Liangliang, SUN Zhe

  DOI: 10.12029/gc20221104002

  Abstract: (210) HTML (0) PDF (2.45 MKB)(1897)

  Abstract:

  [Objective] To assess deep granite type geothermal resource potential of Wendeng area in Shandong peninsula, [Methods] we established discrete fracture network model of hydraulic fracturing based on the geological data, the deep well temperature data, core physical and mechanical test results. The potential created heat reservoirs were simulated for target reservoir. According to the fracturing results, a coupled numerical model of seepage and heat transfer in fractured heat reservoir is established using TOUGH2-EOS1-MINC code. The influence of fracture spacing, well pattern and injection rate on productivity is studied. [Results] The results show that natural fractured reservoirs with stress shielding should be selected as the target reservoirs in deep geothermal exploitation. Large well spacing should be maintained, and reservoirs with overdeveloped natural fractures should not be selected. For the same heat reservoir, the variation of each performance index of five-well mode and three-well mode is similar, but their dynamic variation of productivity is different. The pressure index is more sensitive to the well pattern than the temperature index. The power generation of five-well mode is slightly higher than that of three-well mode for the same reservoir. [Conclusions] When selecting the target reservoir, the high temperature reservoir with moderate natural fractures and high stress shielding should be preferred. Meanwhile, a large amount of fracturing fluid should be injected to drive the reservoir to extend as far horizontally as possible. For the ideal large-scale heat reservoir, the five-well mode should be preferred, but its overall economic benefits should be considered.

• Preliminary study on the“point-surface dual control”model of geological hazard risk in typical mountainous towns in Gansu Province

  wanggaofeng, ligang, sunxiangdong, lihao, tianyuntao, donghanchuan, gaoyoulong, xuyouning, wanghongde, liruidong

  DOI: 10.12029/gc20230220001

  Abstract: (238) HTML (0) PDF (2.68 MKB)(2175)

  Abstract:

  Abstract: This paper is the result of mineral exploration engineering. [Objective] Gansu Province is one of the areas with high incidence of geological disasters in China. The scientific construction of a "point-surface dual control" model of geological disaster risks is the key to disaster prevention and mitigation. [Method] Taking Longlin Town as an example, on the basis of on-site refined survey and mapping, multi-phase remote sensing data modelling, indoor test and numerical simulation analysis, the paper expounds the typical urban geological disaster risk management and control technical process with six steps, including geological disaster risk identification, disaster mode research, risk analysis, vulnerability assessment, risk assessment and risk prevention and control countermeasures, and introduces the semi-quantitative risk assessment process of urban risk slope, the quantitative risk assessment method of single geological hazard based on dynamic process and the "point-surface dual control" mode of geological hazard risk have been formed. [Results] (1) The main types of geological hazards in the study area are landslide and debris flow, with a total of 71 hidden danger points of geological hazards developed, 15 of which directly threaten the safety of people''s lives and property. The three types of landslide hazard models are summarized and the geological early identification signs are established; (2) Based on the geological hazard risk zoning of different precipitation frequencies (5%, 2%, 1%), 75.23% of the regions always maintain low risk under different precipitation frequencies, 24.38% of the regional risk level increases with the reduction of precipitation frequency, and 0.39% of the regions always maintain high risk; (3) Based on the results of risk assessment, a comprehensive risk dual control proposal for disaster reduction in towns and specific disaster sites is proposed. [Conclusions] Relevant research can provide technical support for disaster prevention and mitigation, land space planning and control and use control of complex mountain towns.

• Geological characteristics and favorable area prediction of shale gas in Cambrian Wuxun Formation in the southwestern margin of Xuefeng uplift, China

  danyong, yanjianfei, zhangqingyu, malong, nieguoquan, jishoacong

  DOI: 10.12029/gc20220717001

  Abstract: (150) HTML (0) PDF (2.58 MKB)(1781)

  Abstract:

  Abstract: This paper is the result of shale gas geological survey engineering. [Object] In 2020, shale gas shows were first discovered in the Lower Cambrian Wuxun Formation on the southwestern margin of the Xuefeng uplift, but its accumulation conditions and exploration potential are unknown. [Methods] Based on field geological survey and drilling data, combined with organic geochemical analysis, a comprehensive study of the Lower Cambrian Wuxun Formation in the southwestern margin of Xuefeng was carried out. [Results] The results show that: (1) The shale of the Wuxun Formation was deposited in the carbonate outer ramp facies, which is different from the Longwangmiao Formation in central Sichuan at the same time. (2) The organic-rich shale is developed in the middle and lower parts of the Wuxun Formation, and the rock combination is calcareous carbonaceous shale intercalated with thin limestone, with a thickness of 30–80 m, and a long and narrow distribution in the northeast-southwest. (3) The average TOC content of shale organic matter is 1%, the organic matter type is I type sapropelic type, the average Ro is 2.02%, and the degree of thermal evolution is moderate.(4) The content of brittle minerals in shale ranges from 43% to 69%, with an average value of 59.2%, and the content of clay minerals ranges from 16% to 37%, with an average value of 28.2%.Therefore, shale has high siliceous content and high brittleness, which is easy for reservoir stimulation. (5) Shale is a low-porosity and low-permeability reservoir. Organic pores, intercrystalline pores, interlayer pores, and carbonate mineral dissolved pores provide storage space for shale gas enrichment, but at least four stages of structural fractures and The shale cleavage domain caused by tectonic action greatly improves the shale storage capacity. [Conclusion] Comprehensive evaluation indicators such as geochemistry, reservoir physical properties and preservation conditions suggest that the eastern flank of the Xingren syncline in the southwestern margin of Xuefeng can be a favorable area for shale gas exploration.

• Geological characteristics and mineralization of sandstone type uranium deposit in Baiyanhua area, Western Erlian Basin

  LiTong, YuReng’an, RONG Hui, YangTongxu, ZhuQiang, PengShenglong, TangYongxiang, SiQinghong, QuanXiaoqin

  DOI: 10.12029/gc20220718001

  Abstract: (154) HTML (0) PDF (1.66 MKB)(1529)

  Abstract:

  Abstract: This paper is the result of mineral exploration engineering. [Objective] In recent years, the exploration of sandstone uranium ore in the north has progressed rapidly, and Baiyanhua uranium ore is a newly discovered medium-sized sandstone uranium ore source in the Chuanjing Depression of the Erlian Basin. The systematic study of sandstone uranium ore in Baiyanhua area is intended to provide some valuable references for the prediction of sandstone uranium ore search and the study of mineralization pattern in Chuanjing Depression of Erlian Basin. [Methods] Based on drilling data compilation, map compilation study, systematic sampling, microscopic analysis, and geochemical data compilation, the author elaborates the geological conditions of ore formation, ore body distribution, ore characteristics, and the tectonics, sedimentary filling, and fluid action of Chuanjing Depression in the mining area, and discusses the sandstone type uranium ore formation pattern in this area. [Results]The main ore-bearing level in the study area is the upper section of the Lower Cretaceous Saihan Formation, and the ore bodies are relatively gently spreading in the east and high west. The uranium minerals are mainly uraninite, mainly in gray and dark gray-black sand conglomerates. In the region, the braided river-delta system is mainly developed, the sand bodies are widely distributed and well connected, and the redox zone is developed in the center of the river, which provides favorable conditions for regional mineralization by mineralizing fluids and reducing gas transport and uranium source material transport. [Conclusion] The mineralization pattern of uranium ore in Baiyanhua area is that the uranium-rich fluids from the Baiyanhua Bulge occurred at the end of sedimentary interruption in the upper part of the Lower Cretaceous Saihantala Formation, and the uranium ore bodies were formed by diving and infiltration of uranium-rich fluids from the Baiyanhua Bulge, and the Baiyanhua Bulge was covered by sediments after the deposition of the Erlian Formation, and interstratified oxidation mineralization occurred in due course.

• Differentiation characteristics and dynamic mechanism of synergistic changes of surface soil water and its salt in different seasons in arid area

  liupengfei, zhangguanghui, cuishangjin, niezhenlong, caole, cuihaohao, wangqian

  DOI: 10.12029/gc20220401007

  Abstract: (165) HTML (0) PDF (1.51 MKB)(1513)

  Abstract:

  Abstract：【Obiective】The object of the study is focusing on the characteristics and dynamic mechanism of the same variation of surface soil water and its salt in different seasons in groundwater level depth area of the northwest inland basin.【Methods】Based on data obtained from the in situ multi-factor high frequency monitoring system in groundwater regulation field site, changing processes of topsoil moisture content, pore water electronic conductivity (ECp), groundwater level depth and so on without the direct influence of precipitation and irrigation infiltration were comprehensively analyzed and studied.【Results】20 cm (shallow part)and 40 cm (deep part) depth soil moisture content in later spring，summer and early autumn were all arranged in descending order. However, the shallow and deep part soil ECp were all arranged in increasing order. The shallow part soil electronic conductivity of saturated leach solution (ECe) was arranged in descending order and the deep part soil ECe was arranged in increasing order. In later spring day variation trends of soil moisture content, ECp and ECe were the same in shallow part , which were different in the deep part soil. In summer day variation trends of shallow part soil moisture content and ECe were the same and that of soil ECp was different from them. However, day variation trends of deep part soil ECp and ECe were the same and that of soil moisture content was different from them. In early autumn day variation trends of soil moisture content, ECp and ECe were all different in shallow and deep part. 【Conclusions】Irrigation is the leading factor of influencing differences of surface soil moisture content and salt among seasons. Evapotranspiration is the major factor of resulting in changes of surface soil moisture content and salt in each season. Moreover, the higher the temperature, the more obvious the effect of the evapotranspiration. Groundwater level depth is an important and regulatory factor of affecting topsoil moisture content and salt. In summer when the groundwater level depth becomes bigger, topsoil salt content obviously decreases. In the study area the critical groundwater level depth of prevention and control of farmland salinization is between 1.6 m and 1.9 m in summer.

• The north-south structure zone of Jilong valley in Xizang (Tibet) and its restriction on the geological safety of the engineering construction across the Himalaya Mountains

  liuhan, sun xianfeng, guo jing, zhang shizhen, gou zhengbin, zhang yujie, li jun, wang baodi

  DOI: 10.12029/gc20220825004

  Abstract: (149) HTML (0) PDF (2.42 MKB)(1657)

  Abstract:

  Abstract: This paper is the result of basic geological survey engineering. [Objective] Jilong Valley will be an important area for major engineering projects across the Himalayas in Tibet in the future for a long time. However, we still lack a systematic understanding of the basic geological characteristics, especially the N-S-trending structure, which may induce unexpected engineering construction risks. [Methods] Field geological survey, joint statistics, geothermal investigation, audio frequency magnetotelluric sounding and calcite U-series dating were conducted to reveal the characteristics of the N-S-trending faults and joints in Jilong Valley, and through this to explore the main engineering geological risks related to the N-S-trending structures. [Results] The N-S-trending faults in Jilong Valley are generally small in scale, partially cutting through the high Himalayan belt, and also the basin controlling faults of Jilong Basin. The formation and sedimentary evolution of Jilong Basin were controlled by the four N-S-trending normal faluts in its east boundary and interior. The seismic rocks near the east boundary faults and syn-sedimentary faults in the basin indicate that the Jilong basin has intermittent activity characteristics. The regional permeable distribution is displayed by the N-S-trending joints, which were formed in a simialr stress field controlled by the N-S-trending rift. [Conclusions] The N-S-trending structure in Jilong Valley are potential engineering geological risk sources, according to its Holocene activity and its control over regional geothermal, and collapse, landslide, debris flow geological disasters. We propose that the North-South structure will be one of the important directions of geological safety risk assessment for the planning and construction of Jilong Valley major engineering project.

• Characteristics of trace and rare earth elements in Dongqiyishan fluorite deposit, Inner Mongolia: Indication of ore-forming material sources

  LIU Tianhang, GAO Yongbao, LIU Jiajun, WEI Liyong, TANG Weidong, LI Zonghui, HE Jiale, LI Jiawei

  DOI: 10.12029/gc20220816002

  Abstract: (237) HTML (0) PDF (1.57 MKB)(1455)

  Abstract:

  Abstract: This paper is the result of mineral exploration engineering. [Objective] The Dongqiyishan fluorite deposit is a super-large fluorite deposit, which is related to alkali feldspar granite in the eastern part of the Beishan metallogenic belt. The orebodies are hosted in alkali feldspar granite, griotte and andesite, which are controlled by the rupture and fracture zones near SN or NE dipping. [Methods] On the basis of studying the geological characteristics of Dongqiyishan fluorite deposit, carry out the studies of rare earth and trace elements geochemistry of fluorite and wall rocks in the fluorite deposit. [Results] The results show that the trace elements curves in fluorites are consistent, and obviously enriched in high-temperature elements such as Bi, Cd and Mo relative to the crust values, indicating that these fluorite samples have the characteristics of high temperature mineralization and homology. Fluorites and alkali feldspar granites have similar geochemical characteristics of rare earth. The Y/Ho ratios of 10 fluorite samples are ranging from 21.02 to 28.52, the La/Ho ratios ranging from 3.58 to 15.23. The samples all falling into the hydrothermal region of Tb/La-Tb/Ca diagram, except one close to the sedimentary. The Sm/Nd ratios of fluorites ranging from 0.26 to 0.42, and the Sm/Nd ratios of alkali feldspar granites ranging from 0.26 to 0.42. The δEu vaule ranging from 0.6 to 0.64, and the δCe vaule ranging from 0.89 to 0.94. [Conclusions] Combined with the geological characteristics of the deposit, It is considered the genetic type of the deposit is medium-high temperature magmatic hydrothermal filled type, which belongs to the tungsten-tin-rare -fluorite metallogenic system related to alkali feldspar granite in the area. The ore-forming fluid of Dongqiyishan fluorite deposit is mainly magmatic hydrothermal. The ore-forming material F mainly comes from the deep alkali feldspar granite body, and the Ca mainly comes from the marble strata.

• Characteristic of faults and its control on hydrocarbon accumulation in Laoyemiao structural belt, Nanpu Depression

  LIU Haiqing, JIN Pengbo, Liu jingdong, Liu Hua, ZOU Juan, Chen lei

  DOI: 10.12029/gc20220910001

  Abstract: (157) HTML (0) PDF (2.50 MKB)(1806)

  Abstract:

  [Objective] The superimposed development of multistage faults is very important to the difference of hydrocarbon migration and accumulation in faulted basins. [Methods] Taking Laoyemiao structural belt in Nanpu Depression, Bohai Bay Basin as an example, the fault assemblage style and its origin, the relationship between fault system and oil and gas reservoir formation were studied based on geological analysis and physical simulation experiment. [Results] The results show that Laoyemiao structural belt developed fault combinations of "ladder" type, "domino" type, compound "y" type, compound anti "y" type. The formation of fault combinations is closely related to the boundary of the fault activity, in which "ladder" type and "domino" type fault combinations formed by the northwest - southeast and nearly north – south direction stress fields in Paleogene, while compound "y" type and anti "y" type fault combinations formed because of late superposition of fracture in Minghuazhen period. The discrete element numerical simulation results show that the existence of large plastic mudstone layers in Dongying Formation is the key material factor leading to the difference of deep and shallow deformation and vertical superposition. [Conclusions] Multistage fault superimposition plays an important role in controlling hydrocarbon accumulation: early faults control depressions and structural belts, late faults control traps and hydrocarbon accumulation, and fault assemblages affect hydrocarbon enrichment strata.

• Diversity of methanogenic communities in the deep geothermal water from the Jizhong geothermal area, China

  ZHEN Shi-jun, ZHAO Jia-yi, ZHANG Cui-yun, YIN Mi-ying, ZHANG Sheng

  DOI: 10.12029/gc20220830002

  Abstract: (131) HTML (0) PDF (980.88 KKB)(1987)

  Abstract:

  [Objective] Understanding the diversity of methanogenic communities in the deep environment is the basis for exploring the origin of early life, extreme environmental life and regulating methane production. However, the diversity of methanogenic communities in the deep carbonate karst-fracture geothermal water is still unclear. [Methods] The deep geothermal water samples were collected for methanogenic marker gene mcrA-based high-throughput sequencing by the pumping tests performed in the geothermal scientific drilling holes located in the Jizhong geothermal area, China to explore the diversity of methanogenic communities in the deep carbonate rock karst-fracture geothermal water. [Results] Results showed that 3 classes, 4 orders and 8 genera of methanogenic communities were detected in the deep geothermal water, of which Methanothermobacter, belonging to Euryarchaeota, Methanobacteria and Methanobacteriales, was dominant methanogens, accounting for 99.85% of the total sequences. The dominant species based on mcrA was closely affiliated with Methanothermobacter wolfeii (similarity 99%, accounting for 71%). The metabolic pathway of methanogens was mainly the pathway of CO2 reduction. The compositions of methanogenic communities in different samples were different, but Methanothermobacter was a dominant genus in all of the samples, accounting for more than 99.77%. [Conclusions] This study reveals that the deep geothermal water from the carbonate rock karst-fracture geothermal reservoirs contains relatively abundant but extremely uneven compositions of methanogenic communities and expands the habitat type of Methanothermobacter, which provides scientific basis for further studying the function of methanogens in the earth ecosystem.

• Characteristics of geothermal resources and carbon emission reduction potential in Dafeng District, Jiangsu Province

  Wu Shanshan, Yao Weijun, Zhou Juan, Jia Zhijie, Wang Dan, Zhu Peng, Yang Binbin

  DOI: 10.12029/gc20220706002

  Abstract: (160) HTML (0) PDF (922.70 KKB)(2115)

  Abstract:

  This paper is the result of geothermal geothermal geological survey engineering. [Objective]Dafeng District，located in the northern part of Yancheng City，Jiangsu Province，is an area with abundant geothermal resources. It is of great practical significance to systematically study the characteristics of geothermal resources for the potential of coal and emissions reduction in the development and proper utilization of local geothermal resources. This is to strive for the strategic goal of achieving peak carbon dioxide emissions as soon as possible. [Methods]By comparing and analyzing the "heat source， channel， reservoir，and cap" of geothermal geological conditions for three typical geothermal wells in Hengbei Village，Holland Flower Sea Geothermal Well，and Milu Town Geothermal Well in Dafeng District，the characteristics of geothermal resources in Dafeng District were studied and summarized. [Results]Through the evaluation of water quality and theoretical calculations of mineable and reserve amounts of geothermal wells in this area，we surmised that the geothermal well development and utilization in this area is mainly towards physical therapy，bathing，and heating. The theoretical total coal-saving amount that can be achieved through the exploitation of the geothermal resources in the three wells is 8，884 tons per year， and the corresponding CO2 emissions reduction is 21，197 tons per year. The theoretical total coal-saving amount that can be achieved through the storage of geothermal water in the resources reserved area of the three geothermal wells in Hengbei Village，Holland Flower Sea Geothermal Well，and Milu Town is 18，885，886 tons，corresponding to a CO2 emissions reduction of 45，061，725 tons. [Conclusions]The results of this study provide basic evidence or references for the exploration and development of geothermal resources and the analysis of carbon emissions reduction potential in the Dafeng District.

• Petrophysical characteristics of bauxite in Ordos Basin and conception of deep exploration and mining

  Li ZhiZhong, Luo TengYue, ZhangYi, Xia Peng, Mu Huayi, Sun Pingping, Wang Jianhua, Wang Xin

  DOI: 10.12029/gc20221009002

  Abstract: (193) HTML (0) PDF (1.72 MKB)(1932)

  Abstract:

  [Objective] Ordos Basin is an important energy base in China, with rich oil, natural gas and coal resources, bauxite, uranium and other mineral resources. Bauxite is abundant around the basin, but there is little research on deep bauxite in the basin. Oil and gas drilling shows that the basin is rich in bauxite resources, with a buried depth of one hundred to four kilometers. If the exploration and mining of deep bauxite can be realized, the situation of insufficient bauxite resources in China will be greatly alleviated. [Methods] The geological characteristics and petrophysical characteristics of bauxite in Tongchuan area, Ordos basin are studied in this paper. [Results] First, the deep bauxite in the basin has obvious electrical characteristics, which is characterized by "four high and two low". With reference to oil and gas logging interpretation methods, bauxite identification standards and bauxite logging interpretation models can be established to obtain diaspore content and complete the evaluation of bauxite; Second, the distribution of bauxite in the basin is controlled by the palaeogeomorphology of the Paleozoic Majiagou Formation, and the ore bed is stably distributed, with considerable resources and great exploration potential; Third, bauxite belongs to sedimentary rock, which has certain porosity and permeability, and presents sandwich structure. The bauxite ore bed with high permeability is often surrounded by clay rock with low permeability, meeting the geological conditions of in-situ solution mining; Fourthly, according to stress sensitivity analysis, bauxite is compressible, and new pores or cracks will appear under certain stress, which can further improve the permeability of the ore bed and increase the possibility of in-situ leaching mining of bauxite. [Conclusions] Logging technology can be used to evaluate the deep bauxite resources in Ordos Basin. In combination with the petrophysical characteristics of bauxite, in-situ leaching mining can be considered for bauxite.

• Discussion on the relationship between taro quality and eco-geological environment in Jibu, Ganxian County, Jiangxi Province

  Wang Zhenli, Zhang Lian, Luo Jianlin, Li Fuping, Lei Tianci, Huang chang sheng, yu dong sheng, Deng Tongde

  DOI: 10.12029/gc20220826001

  Abstract: (144) HTML (0) PDF (1014.71 KKB)(2032)

  Abstract:

  This paper is the result of eco-geological survey engineering. [Objective]The purpose of this paper is to study the relationship between the quality of taro and the eco-geological environment, explore the eco-geological mechanism that the eco-geological environment to create the special flavor of taro, provide a scientific basis for the selection or improvement of the eco-geological environment for taro planting, and provide a reference for the research of related disciplines. [Methods] Study was carried outfrom the aspects of geological construction control, soil parent material traceability, soil physics, soil geochemistry, biogeochemistry, etc.Systematic sampling of rocks, soil, waterand plants was donein the core area and the control area of the taro. Themineral elements, organic nutrients and main indexes of physical properties of farmland soilwere detected. The test data were analyzed and processed by a variety of methods and studied comprehensively. [Results] The results show that:① The main indexes reflecting the unique flavor of taro were higher than those in the control area, such as protein, energy, carbohydrate, vitamin B, starch, amino acid, etc. ② The essential elements K, P, Zn and S played a major role in the formation and improvement of taro flavor substances, followed by Fe, Mg, Cl, Ni, Mn, Ca, Cu and SOM. ③ The average soil particle size is small, the soil bulk density and soil compactness is low, the soil burning reduction and pH value is moderate, and the soil moisture and soil Eh value is higher, the soil is well cultivable. [Conclusions] The unique flavor of Jibu taro is the product of the superposition effect of excellent soil physical, soil geochemical and biogeochemical characteristics caused by a unique eco-geological environment.

• Thermochronology of Meso-Cenozoic uplift and tectonic growth of the Longmenshan Thrust Belt

  JIN Wenzheng, BAI Wankui, YE Zhixu

  DOI: 10.12029/gc20220306001

  Abstract: (148) HTML (0) PDF (1.47 MKB)(2354)

  Abstract:

  Abstract: This paper is the result of geological survey engineering. [Objective] In order to discuss the relationship between the vertical tectonic uplift and the lateral tectonic expansion happened in Meso-Cenozoic in the Longmenshan thrust belt, this paper carries out low-temperature thermal chronology testing and analysis. [Methods] Through the determination and analysis of apatite and zircon fission track age, the characteristics of tectonic evolution are studied. [Results] The study shows that the lengths of apatite fission tracks are within the range of 11.4±2.6~12.2±2.2μm, which can effectively reflect the local tectonic uplift history; the results of thermal history simulation show that the apatite samples have experienced three critical stages, including the rapid tectonic uplift, the stable tectonic stage and the rapid tectonic uplift. Besides, the uplifting events happened in the northern area were earlier than those in the southern area. The cooling rate of each rock sample is within the range of 1.211~6.053℃/Myr. The tectonic uplift rate gradually increases from southeast to northwest, and the time of uplifting gradually becomes late in the same direction. [Conclusions] The tectonic deformation of Longmenshan thrust belt has had the characteristics of piggyback propagation from northwest to southeast since Meso-Cenozoic (150Ma), and it has showed these characteristics again from late Cretaceous to Eocene (70~50Ma), even Oligocene (about 20Ma). The central and western regions of the Longmenshan thrust belt are characterized by multi-stage tectonic uplift and superposition.

• Detrital Zircon U–Pb Age and Provenance Analysis of Dacaotan Formation at Qiagai Area in the West Qinling Orogenic Belt

  gongwenqiang, Su Kui, zhangzhen, gaowei, weiliyong, zhaochao, wangate, hejiale

  DOI: 10.12029/gc20210412001

  Abstract: (156) HTML (0) PDF (1.17 MKB)(2072)

  Abstract:

  There are many disputes about the the age and prowenance of Dacaotan Formation, With clastic rocks of the Upper Devonian Dacaotan Formation at Qiagai area in the West Qinling Orogenic belt as the study object, the authors used LA-ICP-MS zircon U-Pb isotope geochronological method to explore the age and prowenance of Dacaotan Formation. The results show that the detrital zircon ages can be divided into 4 groups: (1)The Archen-Paleoproterzoic(2232-3258Ma); (2)The Mesoproterzoic(1018-1791Ma); (3) The Neoproterzoic(544-999Ma); (4)The Early Paleozoic(417-519Ma). Among which, the Early Paleozoic(417-519Ma) ages data possess the largest proportion, accounting for about 39.6% of the total data. The lesser is the Neoproterzoic(544-999Ma) ages, about 37.3%. The other two groups ages possess a smaller proportion. Preliminary analysis show that, the provenance source of Dacaotan Formation were much more complicated and characterized by obvious diversity and periods, derived from northern margin of western Qinling orogenic belt, the eastern part of the Qilian orogenic belt and the basement of North China plate. The predominant part among them was the active magmatic arc produced by collision orogen, which come from the northern margin of western Qinling orogenic belt and Qilian orogenic belt during the Caledonian period.

• Water quality, genetic model, and potential development and use of the Hoh Xil Budongquan spring on the northern Qinghai–Tibet Plateau

  FU Changchang, LI Xiangquan, ZHANG Wenjing, CHENG Xu, BAI Zhanxue, LI Jinqiu

  DOI: 10.12029/gc20220426002

  Abstract: (264) HTML (0) PDF (1.46 MKB)(2185)

  Abstract:

  Abstract: This paper is the result of hydrogeologic survey engineering. [Objective]Budongquan spring is in the region of Hoh Xil on the northern Qinghai–Tibet Plateau. It is a typical sub-surface spring with discharge that ascends to the surface through taliks in the permafrost. It is an important water supply for the Qinghai–Tibet railway and the construction of small towns along the railway. Therefore, it is very important to understand its formation and water characteristics. [Methods] In this paper, we evaluated spring water quality using the single index evaluation method. We analyzed water storage, circulation, and sources of main chemical components by examining the local geology, environmental isotopes, and hydrochemistry. [Results] Results show that Budongquan spring water quality is in class V throughout the year. It is in class V in terms of total hardness, SO42?, and Cl?, and in class I–II in terms of toxicological and heavy metal indices. Nearby glacier meltwater and river water are in class I–II. The spring is mainly recharged by glacial meltwater from the southern slope of Kunlun Mountains, atmospheric precipitation, and surface river water. Average cycle length is less than 5–10 years. Groundwater flow follows the talik zone along the northeast-trending active normal faults. Budongquan spring is formed by the surfacing of groundwater that is blocked by the west-northwest-trending active reverse faults. Its chemical composition is mainly determined by evaporation, and presence of and interaction with magnesium salts and carbonate rocks. [Conclusions] To meet standards for drinking water, we recommend mixing spring water with river water at a ratio of 1:2.

• 7.8-7.4 kacal BP Environment of Rich Diatom Layer and Relative Sea Level Change in the South Plain of the Haihe River, Tianjin

  Fang Jing, Wang Fu, SHANG Zhiwen, YAN Xia, KANG Qinwei, QU Yinghui, WANG Tianjiao, LIU Yufei

  DOI: 10.12029/gc20210725002

  Abstract: (169) HTML (0) PDF (980.39 KKB)(2069)

  Abstract:

  【Objective】In order to study the diatoms indication significance to the sea level and the maximum transgression range, 【Methods】this paper analyzes the diatoms and AMS 14C dating data from three 30m deep drilling cores collected near Chenier V of northern Cangzhou, Bohai Bay. 【Results】The results show that diatoms are rare in these drilling cores, and there is only one diatom rich layer in each core, which is composed of peat and humus gray clay. The thickness of the layer is 10 cm to 60 cm, and thinner from seaward to landward. 7473 cal BP, site of DC01 changed from a sea water influenced swamp environment to a fresh water swamp environment, indicating a relative sea level lower than -6.37m; 7513 cal BP，site of QX02 was transformed from saltmarsh environment (zone I) to sea water influenced shallow swamp, then to salt marsh environment (zone III), The elevation of the boundary between zone I and zone II indicating a relative sea level of -6.68m. 7836 cal BP, site of QX01 was transformed from a freshwater swamp (zone I) to a salt marsh environment (zone II). The boundary between zone I and zone II indicating a relative sea level of -7.68m.【Conclusions】Relative sea level raised ~1m during these ~350 years, and the sea water affected the area to the west of the Chenier V. The salt marshes and freshwater swamps were the main environmental types near the transgression maximum in the Early-Mid Holocene. Under the background of modern sea level rise, marshification is a major environmental problem that modern coastal areas must face.

• Apatite Fission Track Analysis of Tectono-thermal History in the Xiushui area, southern Songliao Basin

  CHEN Shuwang, SUN Shouliang, ZHANG Tao, Barry P. Kohn, Andrew Gleadow, LIU Yan, Ling Chung, LI Yongfei, DING Qiuhong

  DOI: 10.12029/gc20210407001

  Abstract: (166) HTML (0) PDF (988.50 KKB)(2083)

  Abstract:

  【Objective】The tectono-thermal history of the Cretaceous fault basins in the Songliao peripheral area had not been well explored. The Xiushui basin is a new exploration area with high hydrocarbon potential in the southern part of the Songliao peripheral area. The reconstruction of the burial and thermal history of the Xiushui basin has become an important issue for hydrocarbon exploration in this area. 【Methods】Based on five samples from the well LFD1 in the Xiushui Basin, burial and thermal history as well as hydrocarbon source rock evolution history of the Xiushui basin were studied using apatite fission track methods. 【Results】The results show that the Xiushui basin reached its maximum burial depth in the late Early Cretaceous, and then uplift continued and denudated about 2000m. The terrestrial heat flow value increased linearly with time during the initial subsidence period, reaching the maximum value of about 100.5 mW/m2 at about 120Ma, and then experienced a three-stage cooling process, i.e., rapid cooling, then slow cooling, and finally rapid cooling. The heat flow pattern is similar to and comparable with the adjacent Zhangqiang Depression and the Songliao Basin. 【Conclusions】The reconstruction results of the burial and thermal history of the well LFD1 indicate that the hydrocarbon source rocks of the third member of the Yixian Formation entered the oil generation window around 90 Ma, and thereafter, due to the uplift and cooling of the formation, the thermal evolution of the source rock ceased, thus remain unchanged to date. 【Key words：】Burial history; Thermal history; Apatite Fission Track; Xiushui basin; southern Songliao Basin; oil-gas geological survey enginnering 【Highlights：】 1. Burial and thermal history as well as hydrocarbon source rock evolution history of the Xiushui basin were studied using apatite fission track methods for the first time, which lays a foundation for further oil and gas exploration. 2. The regional paleothermal flow shows a trend which the Songliao basin is the highest and gradually decreases to the south, and the reasons for this trend are discussed.

• Exposure risk and genesis of groundwater fluoride contamination from Huaihe River Plain, China

  XU Naizheng, LIU Lin, WANG Hesheng, LI liang, GONG Jianshi, TAO Xiaohu, TAN Mengjiao

  Abstract: (224) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  [Objective] Fluoride (F-) is ubiquitous in groundwater and it is listed as Class III specific carcinogen by International Agency for Research on Cancer. Presently, Huaihe River Basin is identified as a region with F- rich groundwater in China. In order to comprehensively evaluate groundwater F- exposure risk in this basin, this study is to assess its risk magnitude of investigating wells and to predict its risk probability in at unmonitored points based on the recently obtained high-density hydrochemical data. [Methods] This study is to assess the risk magnitude and likelihood for F- rich groundwater in Huaihe River Plain, China using Risk Magnitude and Indicator Kriging methods, and discusses how it formed additionally. [Results] The results show F- concentrations from 5575 investigating wells are in the range of 0.01~5.45 mg/L, with a median of 1.02 mg/L and a mean of 1.97 mg/L, respectively. F concentrations in plain areas are significantly higher than those in hilly areas. There are 548 (9.83%) wells with High Risk Magnitude, and 576 (10.33%) wells with Very High Risk Magnitude, which are predominant positioned in inland plain. Compared with deep groundwater, shallow groundwater exhibits higher F- levels and spatial variability. Based on the prediction of shallow and deep Risk Probability maps, the potential high F- hazard areas over shallow groundwater encompass more than 5137 km2, while the counterpart over deep groundwater is 864 km2; where 3.14 million people are estimated to be potentially exposed to F- contamination. The Risk Probability map of shallow groundwater shows a similar spatial pattern with that of deep groundwater, and both Risk Probability peaks are located in inland plain areas. [Conclusions] It is the main route for inhabitants exposed to F- through drinking groundwater. The spatial coincidence of high F- Risk Probability and high incidence rate of fluorosis observed in inland plain, which might suggest that groundwater F- level is related to the fluorosis cluster. F- rich groundwater is of in-situ origin, and F- is manly derived and released on fluorite dissolution. Besides, alkaline desorption and evaporation concentration affect the formation of high F- groundwater. This paper carried out research on exposure risk of F- rich groundwater from Huaihe River Plain, China, which results can provide scientific basis for the rational utilization and management of regional groundwater.

  • 1

Volume 52,2025 Issue 2

• China National Digital Geological Map (Public Version at 1:200 000 Scale) Spatial Database

  Chenyang LI, Xinchun WANG, Chunzhen HE, Xuan WU, Zhaoyu KONG, Xiaolei LI

  2019,46(S1):1-10, DOI: 10.12029/gc2019Z101

  Abstract: (6912) HTML (4294) PDF (1.47 MKB)(63493)

  Abstract:

  As the only one of its kind, China National Digital Geological Map (Public Version at 1:200000 scale) Spatial Database (CNDGM-PVSD) is based on China's former nationwide measured results of regional geological survey at 1:200 000 scale, and is also one of the nationwide basic geosciences spatial databases jointly accomplished by multiple organizations of China. Spatially, it embraces 1163 geological map-sheets (at scale 1:200 000) in both formats of MapGIS and ArcGIS, covering 72% of China's whole territory with a total data volume of 90 GB. Its main sources is from 1:200 000 regional geological survey reports, geological maps, and mineral resources maps with an original time span from mid-1950s to early 1990s. Approved by the State's related agencies, it meets all the related technical qualification requirements and standards issued by China Geological Survey in data integrity, logic consistency, location accuracy, attribution fineness, and collation precision, and is hence of excellent and reliable quality. The CNDGM-PVSD is an important component of China's national spatial database categories, serving as a spatial digital platform for the information construction of the State's national economy, and providing information backbones to the national and provincial economic planning, geohazard monitoring, geological survey, mineral resources exploration as well as macro decision-making.

• A preliminary study of the Triassic large-scale mineralization in China and its geodynamic setting

  MAO Jing-wen, ZHOU Zhen-hua, FENG Cheng-you, WANG Yi-tian, ZHANG Chang-qing, PENG Hui-juan, YU Miao

  2012,39(6):1437-1471, DOI:

  Abstract: (14965) HTML (0) PDF (18.37 MKB)(56240)

  Abstract:

  Abstract：Triassic tectonic evolution in China is characterized by high intensity and wide influence. However, the metallogenic study related to the major Triassic tectonic events has obviously been lagging behind. This paper preliminarily and systematically discusses the space-time distribution and basic characteristics of the large scale Triassic mineralization in China based on the latest research achievements. Triassic deposits in China are distributed mainly in the two main Triassic orogenic belts of the Kunlun-Qinling orogenic belt and the Red River - Ailaoshan orogen belt and their adjacent regions; Besides, there are a series of polymetallic deposits developed in the three intraplates of southern China, northeastern China and Xinjiang area. Major types of Triassic deposits mainly include： ① Cu-Ni sulfide deposits related to basic-ultrabasic rock; ② porphyry Cu-Au, Cu-Mo, Mo deposits, skarn Cu-Pb-Zn, Cu-Fe, Sn, W deposits and vein-type Au deposits related to intermediate-acid rocks and acidic plutons; ③ pegmatite-type rare metal deposits related to high temperature gas-fluids; ④ orogenic Au deposits related to tectonic-hydrothermal activities in the orogenic process; ⑤ MVT Pb-Zn deposits related to basinal fluids in the orogenic process; ⑥ carbonated vein-type Mo deposits related to mantle fluids. Most of the Triassic deposits in the Kunlun-Qinling orogen belt were mainly formed in collisional stage, or in the post-collision setting. In East Qinling area, the Triassic deposits are dominated by Mo, Au, with the formation ages mainly concentrated in 233-221Ma. In contrast, Au deposits and Pb-Zn deposits of Triassic are widely distributed in West Qinling area, Au deposits are distributed along the NW-trending brittle-ductile shear zones, and Pb-Zn deposits are largely concentrated in the two targe basins of Xicheng and Fengtai, whose metallogenic epochs are mainly in the Late Triassic (232-214Ma). In East Kunlun area, newly discovered Cu-Mo-Fe polymetallic deposits were formed in 240-210 Ma. Influenced by Neo-Tethys evolution, Triassic metal mineral resources are scattered in the Red River - Ailaoshan orogen belt, mainly distributed in Zhongdian ancient island arc, Yunnan-Guizhou-Sichuan border area in the east of the orogenic belt and Dulong area of southeast Yunnan. In Zhongdian area, the metallogenic ages are concentrated in 228-201Ma and their distribution shows the characteristics of porphyry-skarn Cu deposits in the middle part and porphyry-epithermal Cu-Pb-Zn deposits and Au deposits on both north and south sides. The dating results obtained in recent years indicate that Pb-Zn deposits in Yunnan-Guizhou-Sichuan border area were mainly formed in Triassic. Moreover, a series of Triassic W-Sn deposits have been discovered recently in Dulong area of southeast Yunnan, whose peak age is 214-209Ma. In addition to the two main collision belts, rare metal and W-Sn deposits in South China, rare metal and Mo deposits in Xinjiang, porphyry Mo deposits, Cu-Ni sulfide deposits and vein type Au deposits in Northeast China and its adjacent areas were also formed in Triassic, and all of these deposits were closely related to the collision regime, most Triassic deposits in South China were related to EW-extending tectonic-magmatic systems and derived from the emplacement of aluminum granite resulting from the remelting of thickened crust. The mineralization of Triassic deposits in Northeast China and its adjacent areas, Xinjiang, and some neighboring areas of Mongolia and Russian Altay as well as Siberia were probably related to mantle plume activities.

• Source-reservoir-cap rock combination based on sequence framework of the Ediacaran system in western Xuefeng Mountain area

  LI Xu-bing , ZHAO Can, LIU An, WEI Kai, LI Jitao

  2013,40(5):1493-1504, DOI:

  Abstract: (8115) HTML (0) PDF (11.16 MKB)(54733)

  Abstract:

  Abstract：This paper divided and depicted in detail two second-order sequences and seven third-order sequences which are regionally well correlatable according to the Ediacaran system, by employing the research method of sequence stratigraphy “from lithofacies to meter-scale cycle,from depositional facies to sequence classification”. With the reservoir as the center, the authors mainly studied the temporal and spatial distribution of source rocks and reservoirs based on sequence framework, and comprehensively considered the matching relationship of source rocks and cover rock affecting reservoir formation. The source-reservoir-cap rock combinations in carbonate rock of the Ediacaran system were divided into 3 types, i.e., boundary type, transgression type and high water type. The findings indicate that the source-reservoir-cap rock combinations associated with sequence boundary in the study area have the most superior initial geological condition, the high water type is usually combined with the karst or boundary type, thus serving as another source-reservoir-cap rock combination with obvious effectiveness.

• Geochemical features and ages of the intrusive rocks from Yantan belt in Beishan area of Xinjiang and their geological implications

  QU Cui-xia1, YANG Xing-ke1, HE Hu-jun1, GAO Ping2, SONG Hong-ye3

  2013,40(5):1409-1420, DOI:

  Abstract: (8469) HTML (0) PDF (8.78 MKB)(45249)

  Abstract:

  Abstract：This paper deals with petrologic and geochemical features and zircon U-Pb isotope ages of the intrusive rocks from Yantan belt in Beishan area，which are mainly composed of quartz diorite, granodiorite, monzonitic granite, K-feldspar granite, granite and granite-porphyry, belonging to high-K calc-alkaline and calc-alkaline series; All the rocks are characterized by enrichment of LREE，depletion of HREE and strong Eu negative anomalies. The trace elements are enriched in LILE(Rb, Th), and depleted in Sr, Nb, Ta evidently. The zircon SHRIMP U-Pb ages of the quartz diorite and granite are (296±4.1) Ma and (294±3.7) Ma respectively，both of the data are consistent within test errors, suggesting that the rocks were formed at the beginning of the early Permian period. An analysis suggests that these intrusive rocks are I-type granite which are indicative of the underplating of the mantle material into the lower crust and the formation of these rocks in the post-collision tectonic environment after the closure of Beishan rift. The result shows that the Beishan rift was closed in the early Permian in the study area.

• Zircon U-Pb dating of Neoproterozoic tuff in South Gaungxi and its implications for stratigraphic correlation

  GAO Lin-zhi1, LU Ji-pu2, DING Xiao-zhong1, WANG Han-rong2, LIU Yan-xue1, LI Jiang2

  2013,40(5):1443-1452, DOI:

  Abstract: (9126) HTML (0) PDF (9.21 MKB)(42475)

  Abstract:

  Abstract：In the zircon study of bentonite from the Danzhou Group and overlying strata of the Nanhua System, the authors accurately determined the age of (801±3) Ma for zircon from the Hedong Formation and (778±6) Ma for zircon from the Gongdong Formation. (778±5) Ma is the age of zircon from the Chang’an Formation, which is the bottom of the Nanhuan System, and (661±7) Ma is the age of zircon from Datangpo Formation of the intraglacial period. Some zircon ages of tuff bedding were reported for the first time from the Sibao and Xiajia Groups in Guangxi and Guizhou. In combination of the SHRIMP U-Pb age of the granite (834±4 Ma) which intruded into the Sibao Group (842±13 Ma) and the SHRIMP U-Pb age of (837±7) Ma of Bendong granite, the authors hold that the Sibao Group is Late Neoproterozoic strata below the strata of 820 Ma. These isotopic data are very important for us to redefine the age of the Sibao Group and to conduct regional correlation of strata of the corresponding period as well as to study tectonic evolution. There is an angle unconformity between the Sibao Group and overlying Danzhou Group and a nonconformity between the Danzhou Group and the Nanhuan System, suggesting the existence of three levels of tectonic factor. The revised age column will influence the whole metamorphosed basement in the Jiangnan Orogen and the constraints on the relationship of the cover strata in South China.

• Determination of the age of gold deposits in southeastern Guizhou: with a discussion of the Caledonian Hunan-Guizhou gold ore belt

  ZHU Xiao-qing1, WANG Gan-lu2, LU Huan-zhang3, WU Xue-yi1, CHEN Wen-yi4

  2006,33(5):1092-1099, DOI:

  Abstract: (2337) HTML (0) PDF (810.42 KKB)(41824)

  Abstract:

  Abstract：Gold deposits in southeastern Guizhou are quartz vein type gold deposits hosted in the Neoproterozoic low-grade metamorphic series. The protoliths of the metamorphic rocks are represented by a volcanic-sedimentary sequence composed of tuff, tuffaceous sandstone and siltstone with a distinct rhythmic ribbon texture, reflecting an environment of turbidite sedimentation. The occurrence of quartz veins is controlled by anticlines and shear faults. Two types of vein may be distinguished: conformable interlayer veins and filling veins in fracture zones. The mineral composition of quartz veins is rather simple, and in addition to quartz, the veins mainly contain sulfide minerals and some minerals captured from wall rocks. Rb-Sr and isochron dating of inclusions in quartz from five gold deposits indicates that their age is Caledonian, which is consistent with the age of gold deposits of the same types of gold deposit in western Hunan adjacent to Guizhou. A Caledonian Hunan-Guizhou gold belt of gold has been delineated according to the lithology of host strata, geological evolution and structural environment, which will be of great reference value for mineral prospecting.

• Geochemical characteristics and sedimentary-tectonic setting of the Cambrian sandstones and mudstones in Dayaoshan-Damingshan area,Guangxi

  DU Xiao-dong1, 2, ZOU He-ping1, 2, SU Zhang-xin1, LAO Miao-ji1, CHEN Shi-ai1, DING Ru-xing1, 2

  2013,40(4):1112-1128, DOI:

  Abstract: (10953) HTML (0) PDF (12.36 MKB)(37913)

  Abstract:

  Abstract：The Daoyaoshan-Damingshan area is located in the southwestern section of the Qinzhou-Hangzhou juncture between the Yangtze Block and the Cathayian Block．The study of the early Paleaozoic sedimentary environment and tectonic setting of this area is a key to understanding the geotectonic problems in South China. Major and trace elements of 27 pieces of samples from Cambrian sandstones and mudstones in this area were analyzed and discussed. The samples generally have high ratios of Al2O3/TiO2 ( in the range of 11.95~36.26,20.81 on average) and lower ratios of Rb/Cs（in the range of 13.02~68.27, 32.21 on average） and Cr/Zr（ranging 0.14～1.15,averagely 0.59）. Geochemical characteristics, such as the plots of Ni-TiO2,Th/Sc-La/Sc and La/Th-Hf , indicate that the Cambrian sediments in the Daoyaoshan-Damingshan area were mainly sourced from the upper crustal felsic quartz rocks,with the addition of a small amount of igneous sources and ancient recirculation sediments．The distribution of trace and rare-earth elements and the data of La-Th-Sc,K2O/Na2O-SiO2, δCe,δEu,Tb/Yb,La/Sc,La/Th,Th/U as well as the comparison with different tectonic settings show that the study area belonged to a passive continent-marginal setting. In addition, such evidence as the marks of shallow-sea deposits,the data of sedimentary palaeogeography,regional geology and geochemistry suggests that during the Early Paleozoic there existed no geochemical evidence for the so called “ancient ocean in South China”．

• Timing and stages of the Permian oil-gas accumulations in northeastern Ordos Basin

  CHEN Gang1, LI Shu-heng2, ZHANG Hui-ruo2, DING Chao1, YANG Fu1, LEI Pan-pan1

  2013,40(5):1453-1465, DOI:

  Abstract: (8007) HTML (0) PDF (6.42 MKB)(35946)

  Abstract:

  Abstract：Geochronology of oil-gas accumulation (OGA) is a key research frontier for petroleum reservoir-forming dynamics in the multi-cycle superimposed basin. The OGA timing and stages of the Permian reservoirs in northeastern Ordos Basin (OB) are constrained in this paper by K-Ar dating of authigenic illite (AI) and indirect dating of fluid inclusions (FI) from oil-gas-bearing sandstone core samples of the Lower-Upper Permian period. AI dating results of the Permian samples show a wide time span of 178～108 Ma and a spatial decreasing trend from 178～122 Ma in the south to 160-108 Ma in the north. The distribution of the AI ages generally reveals 2-stage primary OGA of the Permian reservoirs, which were mainly developed in the time spans of 175～155 Ma and 145～115 Ma respectively with 2-peak ages of 165 Ma and 130 Ma. Additionally, the FI temperature peaks of the samples and their projected ages on AFT thermal path of the FI-host rocks not only statistically present two groups with a low and a high peak temperatures in ranges of 90～78 °C and 125～118 °C, respectively corresponding to 2-stage primary OGA processes of 162～153 Ma and 140～128 Ma in the Permian reservoirs; nevertheless, there is also a medium temperature group with the peak of 98 °C in agreement with a secondary OGA process of ca. 30 Ma in the Upper Permian reservoirs. An integrated analysis of the AI and FI ages with the regional tectonic thermal evolution reveals that the Permian reservoirs in the northeast OB mainly experienced 2-stage primary OGA processes of 165～153 Ma and 140～128 Ma during the Mid-Early Mesozoic multi-cycle burial heating processes, and then the Upper Permian reservoirs further experienced 1-stage secondary OGA of ca. 30 Ma in accordance with a critical tectonic conversion from the slow to rapid uplift-cooling process during the Late Cretaceous-Neocene period.

• Characteristics and metallogenic regularities of ore deposits on the western slope of the southern section of the Da Hinggan Mountains metallogenic belt

  ZHANG Wan-Yi1, 2, NIE Feng-Jun3, LIU Shu-wen2, ZUO Li-Yan2, SHAN Liang2, YAO Xiao-Feng2

  2013,40(5):1583-1599, DOI:

  Abstract: (8019) HTML (0) PDF (6.12 MKB)(35742)

  Abstract:

  Abstract：Located in Chagan Obo－Aououte－Chaobuleng area along the southern edge of the Siberian plate, the study area on the western slope of the southern section of the Da Hinggan Mountains metallogenic belt (northern Dong Ujimqin Banner of Inner Mongolia ) is controlled by multiple subduction, collision and connection of North China platform, and characterized by widely exposed Paleozoic volcanic-sedimentary rocks, complex structures, all kinds of intense magmatic activities, and widespread ore deposits and ore spots. The study area has special favorable geological structure and setting for mineralization. On the basis of geological survey, the authors studied geological features of ore deposits and genesis of typical deposits, and summarized metallogenic regularities of this area. The results show that there are many kinds of ore deposits such as iron, silver, copper, lead, zinc, gold, and molybdenum. The δ34S values of typical deposits vary from +1‰ to +8.6‰. The sulfur isotope compositions show different sources. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of different samples vary in ranges of 17.949～18.529, 15.370～15.691 and 37.653～38.460, respectively. The lead isotope compositions indicate that the sources of lead were wall rocks and granites. The main types of ore deposits were skarn deposits and medium-low temperature hydrothermal deposits, which were significantly affected by formation, structure and magma. In general, the wall rocks of metal deposits were Ordovician, Devonian and Carboniferous volcanic- sedimentary rocks. Skarn deposits were formed near the contact zone between the carbonate and granite, while medium-low temperature hydrothermal deposits were formed in argillite and sandstone without carbonate. NE- and NW-trending faults were important ore channels or places for ore storage. The regional ore deposits in the study area were formed in three periods, i.e. Hercynian, Indosinian and Yanshanian. They were closely related to granite intrusions in temporal and spatial distribution.

• The ore-control structural features and ore-host regularity of Chaihe-Moguqi area in the Da Hinggan Mountains

  SUN Zhong-shi1, LIU Si-chuan1, 2, ZHENG Chang-qing1, TAN Lian2, SUN Li1, LI Juan1, SHI Lu1, CUI Fang-hua1, FAN Si-qi3

  2013,40(2):529-537, DOI:

  Abstract: (7690) HTML (0) PDF (5.75 MKB)(33077)

  Abstract:

  Abstract：Ore-controlling structure is always one of the difficulties in the study of hydrothermal deposits. With Chaihezhen-Moguqi region of the Da Hinggan Mountains as the study object, this paper puts forward some conclusions on the basis of the 1:250000 geological investigation of. Chaihezhen-Moguqi region. 1. The main ore-controlling structures are Daheishan-Taipingling-Jiguanshan fracture zone and Zalantun City-Haduo River fracture zone, and the formation ages are mainly Hercynian and Yanshanian. 2. Ore-controlling structures mainly show compression, tensile and shear properties, and between the three properties, there existed the conversion between shear and tensile and between shear and torsion, with the principal compressive stress field changing in the directions of E-W, SE-NW to SSE-NNW in succession. 3. The regularities of the main ore-controlling structures, the branching ore-control structures, and the parallel and inclined ore-controlling structures are summarized in this paper. These regularities, the structures as passageways for ore fluids and the ore source were closely related to deep subduction which produced molten magma. These new ideas are of great significance for the detailed study of geological foundation, metallogenic theory and prospecting work in this region.

• Zircon LA-ICP-MS U-Pb age of Caledonian granites from Precambrian basement in Yunkai area and its geological implications

  WANG Lei, LONG Wen-guo, ZHOU Dai

  2013,40(4):1016-1029, DOI:

  Abstract: (9506) HTML (0) PDF (5.41 MKB)(32891)

  Abstract:

  Abstract：LA-ICP-MS U-Pb dating was conducted for zircons from four gneissic granites in Yunkai area, which were assigned to Precambrian basement rocks or Neoproterozoic intrusion in 1∶250000 geological survey. The dating yielded 206Pb/238U weighted mean of 443.3±2.6 Ma (sample 1009, Lutou Reservoir in Luchuan City), 445.7 ±2.3Ma (sample 1010, Yuedong in Luchuan city), 441.1±2.0Ma (sample 1012, Xieji in Gaozhou city) and 443.7±1.7Ma (sample 1018, Zhusha in Xinyi city), suggesting that these rocks are Caledonian products rather than Precambrian basement or Neoproterozoic intrusive rocks. In combination with previous studies, the authors hold that these granites probably resulted from partial melting of the Proterozoic materials due to the Caledonian orogeny in South China. These results and recently published data (Caledonian) for the so-called Precambrian basement rocks, such as the crystallization age or metamorphic age of gneissic granite and gneiss, indicate that Yunkai area has undergone extensive reformation by the Caledonian orogeny. Actually, the Precambrian basement of Yunkai area mainly consists of gneissic rocks and meta-sedimentary rocks, which serve as the representative of the Gaozhou complex and the Yunkai Group, respectively. The Gaozhou complex was formed during the Meso- to Neo-proterozoic and the Yunkai Group might have been formed in the Neoproterozoic. The Paleo- to Meso-Proterozoic crystallized basement does exist in Cathaysia Block, however，which is not so widely distributed as previously thought.

• Shale gas accumulation conditions of Devonian strata in Guizhong depression

  WANG Kai-ming

  2013,40(2):430-438, DOI:

  Abstract: (7718) HTML (0) PDF (5.34 MKB)(32161)

  Abstract:

  Abstract：Using samples from typical sections, drilling data and geochemical information from the Devonian black shale in Guizhong depression of central Guangxi, the authors analyzed the accumulation condition of shale gas reservoirs. The results demonstrate that there exist two suites of excellent marine source rocks in the middle and lower Devonian strata of Guizhong depression, which are characterized by large thickness and extensive distribution, high abundance of organic matter and moderate buried depth, thus possessing basic conditions for the formation of shale gas reservoirs. However, the preservative condition of shale gas is very poor because of the subsequent multistage severe tectonic movements as well as the development of faults and magmatic activities in some areas. Therefore, the central and western areas of Guizhong depression with integrated strata, underdeveloped faults and magmatic activities seem to be the favorable places for shale gas exploration. It is suggested that the preservation condition is very important in exploring shale gas resources under the conditions of high organic thermal evolution extent and subsequent multistage severe tectonic movements. The preservation condition is one of the key factors for shale gas exploration in China.

• Zircon U-Pb age and Sr, Nd, Hf isotope geochemistry of Jingde pluton in eastern Jiangnan orogen, South China

  ZHOU Jie1, 2, JIANG Yao-hui1, ZENG Yong2, GE Wei-ya2

  2013,40(5):1379-1391, DOI:

  Abstract: (7056) HTML (0) PDF (4.86 MKB)(31525)

  Abstract:

  Abstract：Jingde pluton is one of the Mesozoic plutons in eastern Jiangnan orogen of northeast Yangzte Block. New LA-ICPMS zircon U-Pb dating for one granodiorite yielded an emplacement age of (141.0±1.0) Ma. The pluton is composed of monzogranite and granodiorite. New petrographical and petrochemical data show that the pluton is intermediate-somewhat acid (SiO2=66.01%~70.87%), and has high content of Al2O3 (Al2O3=14.91%~16.24%) and rich alkali (K2O+Na2O = 6.64%~8.01% ), with K2O/Na2O value ranging from 0.78 to 1.04. The pluton has relatively low content of MgO, TFe2O3 and P2O5 (MgO = 0.68%~1.06%, TFe2O3=2.0%~3.34%, P2O5 = 0.10%~0.14% ). As for trace elements, the pluton is enriched in Sr (189×10-6~452×10-6) with high Sr/Y ratios (23~66) and also enriched in light rare earth elements (LREE) ((La/Yb)N = 13 ~ 58) , but somewhat depleted in Nb, Ta, P, Ti, Y, Yb, with slightly negligible to positive Eu anomalies (δEu=0.81~1.18), similar to the geochemical characteristics of Mesozoic adakitoid in eastern China. Jingde pluton has relatively high Nd isotopes (εNd(t)=-6.28~-7.32), high εHf (t) values (-6.5~-1.1) and younger tDM2 model ages (1.4~1.5Ga), with mafic microgranular enclaves (MMEs), suggesting the importance of mantle material in the magma source. The mafic magmas ascended and heated the lower crust, triggering the partial melting of the lower crust to form the Jingde pluton, with the input of mantle-derived materials.

• An analysis of the source and the sedimentary system of the Carboniferous Benxi Formation in Yanchang area of Ordos Basin

  LIN Jin1, 2, LI Yun1, 2, HE Jian1

  2013,40(5):1542-1551, DOI:

  Abstract: (6629) HTML (0) PDF (5.02 MKB)(31415)

  Abstract:

  Abstract：By investigating data extracted from well cores, field outcrop samples, thin sections, cathodoluminescence images and the laboratory tests, the authors conducted a comprehensive study of the Carboniferous Benxi Formation in Yanchang area of Ordos Basin and then deduced its source directions from the angles of the mineral composition, genetic type, paleocurrent features, and enrichment regularities of rare earth elements. On such a basis, the authors analyzed the sedimentary facies distribution and evolution. It is revealed that from north to south in the study area, the sandstone grains decrease in size and increase in psephicity; the quartz cluster cathodoluminescence images are mainly fuscous, light-dark brown in color, indicating metamorphic genesis. The debris component is chiefly metamorphic debris, which is up to 85.1%. The paleocurrent of field outcrop moved northward, from northwest southward and southeastward. the distribution of the rare earth elements is quite similar to the Daqingshan old land at the northeast edge of the basin. It is thus concluded that the Benxi Formation primarily originated from Yinshan-Alxa in the north. The second stage of Benxi Formation in late Carboniferous epoch constituted a major turning point in the Upper Palaeozoic evolutionary history of Ordos. Due to the invasion of the slowly-subsiding sea water from the east, the study area formed a system composed of shallow argillaceous shelf, barrier island-lagoon and lagoon. The first stage was similar to the second stage in general features, but had larger argillaceous shelf and lagoon because of the intense water invasion, which had a good performance in the sand body continuity in parallel with the coastline.

• The principal antimony concentration areas in China and their resource potentials

  WANG Yong-lei1, CHEN Yu-chuan2, WANG Deng-hong1, XU Jue1, CHEN Zheng-hui1, LIANG Ting3

  2013,40(5):1366-1378, DOI:

  Abstract: (9661) HTML (0) PDF (4.74 MKB)(30870)

  Abstract:

  Abstract：Antimony is one of the dominant minerals in China, which was listed as the first global shortage minerals by British Geological Survey in 2011. In this paper, based on the mineral resource potential assessment project, in combination with data available and grade III metallogenic belt research, the authors summarized the characteristics of antimony resources in China and preliminarily assigned antimony deposits in China to 13 large ore concentration areas, with a brief description of their geological characteristics. Meanwhile, based on the existing data and new advances in the exploration of antimony deposits in recent years, this paper makes a comment on the metallogenic characteristics of the six most important antimony ore concentration areas with an analysis of their resource potentials. The authors hold that there are still some blank areas for working as well as some potential prospecting areas around the known mines. The new prospecting direction is also pointed out.

• Zircon LA-ICP-MS U-Pb chronology of magmatic rock in the Baishantang copper polymetallic deposit of Beishan area, Northwest China

  SHAN Liang1, 2, XU Rong-ke3, ZHENG You-ye1, 3, ZHANG Yu-lian4, CAO Liang5, PANG Ying-chun5

  2013,40(5):1600-1611, DOI:

  Abstract: (7424) HTML (0) PDF (5.04 MKB)(30678)

  Abstract:

  Abstract：Beishan area is an important metallogenic belt, and the Baishantang Cu polymetallic deposit is one of the representative porphyry copper deposits. Two kinds of magmatic rocks along ore belt I in the Baishantang ore district were dated by the zircon LA-ICP-MS U-Pb method, which yielded a porphyry granite diagenetic age of （275.0±3.0）Ma (MSWD =1.17) , indicating early Permian. Two groups of ages were obtained for rhyolite porphyry: a magma zircon group of the rhyolite porphyry has an age of （371.1±2.8）Ma (MSWD=1.7) , suggesting late Devonian. The other inheritance zircon group of inheritance zircon with remarkable rounded shape or enveloped in the former group has ages of （2627±35）Ma, （2598±35）Ma, （705±44）Ma, （1722±48）Ma, （1642±51）Ma, （1213±54）Ma, which can be assigned roughly to 2.6 billion years, 1.7 billion years and 1.2 billion years, indicating that the rhyolite porphyry was related to the remelting of the upper-middle crust in late Devonian, as also shown by the geochemical characteristics.

• Late Triassic magma mixing in the East Kunlun orogenic belt: A case study of Helegang Xilikete granodiorites

  CHEN Guo-chao1, 4, PEI Xian-zhi1, LI Rui-bao1, LI Zuo-chen1, PEI Lei2, LIU Zhan-qing3, CHEN You-xin1, LIU Cheng-jun1

  2013,40(4):1044-1065, DOI:

  Abstract: (2988) HTML (0) PDF (8.48 MKB)(29725)

  Abstract:

  Abstract：In the East Kunlun orogenic belt (EKOB), mafic microgranular enclaves (MME) occur frequently in Late Permian-Triassic granitic rocks. In this paper, the authors took Helegang Xilikete granodiorites in the eastern part of the EKOB as an example to study their host rocks and MME in detail. Characteristics of the host rocks and the MME, such as field occurrence, morphology, texture and structure and mineralogy, together with the geochemistry, show that they were cooled and crystallized in a short time immediately after the intrusion of basaltic magma into intermediate-acidic magma and thus have similar distribution patterns to the host rocks in the REE diagram and trace element spider diagram, such as the enrichment of the LREE and LILE and the depletion of the HREE and HFSE, reflecting a typical feature of magma mixing. The result of LA-ICP-MS zircon geochronology implies that the crystallization age of the MME is about 224.9±4.1 Ma, very close to that of the host rock (225±5 Ma), suggesting a crust-mantle magma mixing event at the stage of post-collision in the EKOB in Late Triassic.

• The application of electromagnetic sounding method to deep iron ore exploration：A case study of the Wuyang iron mining area of Henan

  LI Bing1, 2, CHAO Dai-chao3, WEI Ming-jun2, 4, LI Yong-feng2, 5, LUO Zheng-zhuan2, 5, SHANG Jian-ge1

  2013,40(5):1644-1654, DOI:

  Abstract: (6711) HTML (0) PDF (4.27 MKB)(27797)

  Abstract:

  The application of electromagnetic sounding method to deep iron ore exploration：A case study of the Wuyang iron mining area of Henan

• An analysis of structural ore-controlling role in Xiaoqingling area

  YAN Jian-she1, NIU Shu-yin2, FENG Jian-zhi3, SUN Wei-zhi3, SUN Ai-qun2, WANG Xing-cun3, CUI Xie-xiang3, CHEN Chao2

  2013,40(2):538-548, DOI:

  Abstract: (7163) HTML (0) PDF (4.22 MKB)(27403)

  Abstract:

  Abstract：The Xiaoqinling gold ore concentration area is known for its great uplift amplitude, high denudation extent, intense tectonic movement, clear structural features and concentrated distribution of ore deposits. The study area experienced four periods of folding, comprising from early to late plastic flow folding→regional EW-trending main folding →NS-trending crossing superimposed folds→transverse folding of vertical uplift, and was subjected to four periods of shearing, in order of plastic flowing →brittle ductile transpression→ductile brittle tenso-shearing →brittle forward detachment caused by uplift. The main stage brittle-ductile shearing was developed in the main limb of the weak tectonic belt. The third phase ductile-brittle shearing process of Yanshanian period provided favorable ore-hosting conditions for the large-scale injection of ore-forming fluids and mineralization. Researches show that the ore-forming fluids were mainly derived from the depth and, through the multistage evolution of mantle plume, injected into the ductile shear zone to form ore deposits via accumulation. In the ore district, there often exist one or two main ore veins which control more than 50% of metallic reserves.

• The reformation of the Dongbo ultramafic rock massif in the western part of the Yarlung Zangbo suture zone by subduction-related fluids：Evidence from the platimun-group elements (PGE)

  NIU Xiao-lu1, YANG Jing-sui1, CHEN Song-yong1, LIU Fei1, XIONG Fa-hui1, LIU Zhao1, GUO Guo-lin2

  2013,40(3):756-766, DOI:

  Abstract: (7760) HTML (0) PDF (5.19 MKB)(26072)

  Abstract:

  Abstract：Located in the western part of the Yarlung Zangbo suture zone, the Dongbo ultramafic rock massif is comparable with the Luobusa ultramafic rock massif which holds the largest chromite deposit in China in terms of their petrology and mineralogy. In this paper, the authors attempted to characterize its origin by examining the geochemistry of platinum group elements (PGE), major elements and rare earth elements (REE) of the harzburgites which are the main rocks of the rock mass. The harzburgites are characterized by high abundances of Os (3.52×10-9~4.36×10-9), depleted major element compositions and low REE content (0.89×10-6~1.37×10-6) which is lower than that of the primary mantle, indicating that the Dongbo ultramafic rocks belonged to depleted residual mantle rocks after a significant degree of partial melting and melt extraction. They also have high PGE content (23.97×10-9~31.98×10-9) which is higher than that of primary mantle, and display IPGE-depleted, PPGE-enriched chondrite- and primary mantle- normalized PGE patterns with Pd/Ir being 1.49~2.65. Their chondrite- and primary mantle-normalized REE patterns are all U- or V-shaped with (La/Sm)m being 1.05~3.37 and (Gd/Yb)m 0.28~0.64 (primary mantle-normalized values). These features are consistent with the opinion that the Dongbo ultramafic rocks were formed by the interaction of depleted residual mantle rocks with melts/fluids which were enriched with incompatible elements and PGE, especially IPGE relative to PPGE. In addition, the low Cu/Pd ratios (1226~3448) argue that the melts/fluids should also have high content of sulfides. The authors infer that the melts/fluids that reacted with the residual mantle rocks probably originated from the magmas produced in a subduction-related tectonic setting.