• 10 papers in Geology in China won "Frontrunner 5000——Top Articles in Outstanding S&T Journals of China "
  • "Geology in China" indexed in World Journal Clout Index (WJCI) Report of Scientific and Technological Periodicals (2021)
  • "Geology in China" selected as the Source Journal of "Outstanding S&T Journals of China (2020) "

Editor in Chief:HAO Ziguo

Established in:1953

ISSN: 1000-3657

CN: 11-1167/P

Domestic postal code:2-112

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    Volume 49,2022 Issue 3
      In Focus
    • YANG Weilong, BAI Yuming, LI Yongli, HU Haoyuan, DU Xin

      2022,49(3):683-694, DOI: 10.12029/gc20220301

      Abstract:

      This paper is the result of geological environment survey engineering.[Objective]Phytoremediation technology has been widely used in mine ecological restoration because of its characteristics of green, economic and environmental protection. The investigation and screening of plant species adapted to local habitats around mines is the key link of plant ecological restoration.[Methods]By the method of soil sampling for investigation and laboratory analysis, this work analyzed 11 dominant plants in the abandoned tailing and the surrounding of Baotou, Inner Mongolia. Test the contents of heavy metals, the enrichment and translocation of heavy metals and the contents of heavy metals of the plant root soil, in order to screen fine restoration plants and provide scientific basis for ecological restoration in mining area.[Results]The results showed that the mean contents of Fe, Mn, Cu, Pb, Zn, Cr, Cd, F much higher than the background value of soil in Hetao Plain, geoaccumulation index revealed the pollution level is 2-7, levels of pollution range from mild to moderate pollution to extremely intense pollution. Heavy metal content in plants shows that the content of each element in the underground part of plants is generally higher than that in the aboveground part, the content of heavy metals in most plants exceeded the normal range except for Cu.[Conclusions] Artemisia desertorum and Lepidium apetalum are belong to accumulators, Zea mays, Setaria viridis, Chloris virgata and Calamagrostis epigeios which absorbed a large amount of heavy metals but mainly held in the roots, Suaeda glauca, Chenopodium album, Xanthium sibiricum, Populus alba and Salix microstachya are belong to excluder. According to the absorption and enrichment characteristics of heavy metals in plants, aim to provide reference for the establishment of artificial phytoremediation system in mining areas and the selection of appropriate plant species for the remediation of heavy metal polluted soil in mining areas.

    • LIU Caize, WANG Yonghua, ZHAO Jin, ZENG Qinqin, LEI Fenghua

      2022,49(3):695-705, DOI: 10.12029/gc20220302

      Abstract:

      This paper is the result of agricultural geochemical survey engineering.[Objective] As a heavy metal, cadmium (Cd) mainly enters the food chain through the "soil=plant" system and affects human health. It is great significant to study the accumulation of cadmium in crops to ensure human health and safety.[Methods] Soil and rice samples from Nanchong, Bazhong and Guang'an in the northeast Sichuan were collected. The cadmium content in soil and rice was analyzed by ICP=MS, and the data were statistically analyzed by CART decision tree and correlation coefficient methods.[Results] The research shows that the cadmium content of the soil in the northeast Sichuan is relatively low, ranging from the safety threshold. In contrast, the cadmium content of the rice (brown rice) varies from 0.002 to 0.803 mg/kg and with an average value of 0.076 mg/kg, 14.0% of which is above the safety threshold. The daily cadmium intake of adults reaches 90.4 μg/d in the region with excessive cadmium in rice, exceeding the permissible cadmium intake of 60 μg/d.[Conclusions] The phenomenon that cadmium content does not exceed the safety threshold in soil but it does in rice may be related to the characteristics of low pH, low CaO and high SiO2 of the soil. This recognition is great significance for guiding grain production in this region. 0.071 to 0.92 mg/kg and with an average value of 0.254 mg/kg. The cadmium content of almost all (99.9%) soil samples is below

    • YANG Yanlin, JING Jing, ZHAO Yongbo, HE Jun, DU Xiaofeng

      2022,49(3):706-715, DOI: 10.12029/gc20220303

      Abstract:

      This paper is the result of hydrogeological survey engineering.[Object]Reveal the characteristics and interaction of D and 18O between surface water and groundwater in the northern new town of Wuhan,[Methods]7 precipitation samples, 6 river samples, 14 reservoir samples, 98 minjing samples, 3 spring samples and 11 borehole samples were collected and measured in 2019, what' s more, 50 monitoring data of Wuhan station from 1986 to 1998 were collected. The research methods of D and 18O spatial analysis and watershed analysis are carried out in this paper.[Results](1) The D and 18O isotopes of precipitation in Wuhan vary with seasons, and the negative correlation between isotopic value and precipitation indicates "rainfall effect", but the no correlation between isotopic value and temperature indicates "no temperature effect". (2) Due to strong evapotransporation, the surface water shows the certain correlation between isotopic value and geomorphic types, and the main stream is enriched in stable isotopic, while the tributaries is depleted; (3) Groundwater such as wells, springs and boreholes are all derived from atmospheric precipitation, and the stable isotopes value of groundwater is related to the buried depth and geomorphic type; (4) During the dry season, the Jiehe River is recharged by upstream reservoir and underground water in the Jiehe basin, and the XiaJiasi reservoir is recharged by underground water in the XiaJiasi reservoir basin.[Conclusion]D and 18O can significantly improve the understanding of the conversion relationship between surface water and groundwater in the northern new town of Wuhan.

    • ANG Xinwei, WANG Tinghao, LI Haiquan, ZHANG Xuan, LUO Lu, LIU Huiying, WANG Simin, XIANG Caifu

      2022,49(3):716-731, DOI: 10.12029/gc20220304

      Abstract:

      This paper is the result of geological survey engineering.[Objective]The Taiyuan Basin is one of the areas where its distribution of beneficial Karst geothermal reservoir and demand of urban heating are well matched. The research on the evolution of Karst geothermal system and the characteristics of genetic elements in Taiyuan Basin has a great significance for the overall development of geothermal resources in this area and the understanding of the distribution of geothermal resources in rift basins.[Methods]Based on the previous research and the latest data of 54 geothermal wells, we analyze the heat source, geothermal reservoir distribution and hydrothermal dynamic characteristics of karst geothermal system in Taiyuan Basin, and also evaluate the geothermal resources by 8 effective structural units.[Results]The results show as flow:(1) The strata of karst thermal reservoir in Taiyuan Basin are mainly developed in the Lower Paleozoic Ordovician,, which is widely distributed in North China Plate. And the evolution of the karst geothermal reservoir has gone through five stages, i.e. the epigenic karstification at the end of the Early Paleozoic, the direct caprock deposition in the Late Paleozoic, the initial formation of the karst geothermal system during Mesozoic, the transformation during the Neogene and the final setting during the Quaternary. (2)The heat source of the geothermal system comes from the high terrestrial heat flow (up to 79.12mW/m2) generated by the Cenozoic rift basin, and the heat transfer mode can be divided into two different types:the strong convection type at the edge of the basin and the heat conduction type inside the basin. (3) The geothermal reservoir property is in the longitudinal and horizontal zonation. In the vertical direction,15-20 effective reservoir sections are identified, with a accumulated thickness of 160~180m, which can be divided into 3-4 layers of main water-bearing section; on the plane, the favorable reservoir belt is mainly controlled by NE trending concealed structure, and the main water-bearing layer is easy to generate a "over-flow" phenomenon during the migration process. The Ordovician reservoir in the middle of the basin with moderately buried (about 400~1900 m) and high temperature (30-75℃) charcteristics is the most favorable exploration and development area. (4) According to the geothermal reservoir volume method, the total geothermal resources of the karst geothermal system in Taiyuan Basin are estimated to be 8.303 billion GJ, which is equivalent to 283 million tons of standard coal.[Conclusions]The annual exploitation of geothermal resources can meet the heating area of 15.02 million square meters. At present, the developed resources only account for 23.3% of the exploitable resources, the development potential is huge.

    • WANG Gaofeng, GAO Youlong, YAO Yahui, TIAN Yuntao, XU Youning, SUN Xiujuan, LI Ruidong, HE Yuanxiao, DENG Bing, YE Zhennan, CHEN Zongliang, GUO Ning

      2022,49(3):732-748, DOI: 10.12029/gc20220305

      Abstract:

      This paper is the result of geological hazard survey engineering.[Objective]Debris flow is a major geological disaster widely distributed in Bailong River Basin and often causes mass casualties. Accurate evaluation of the scale and risk of debris flow is the premise of the early warning and prediction of debris flow. Reasonable construction of risk prediction model is the key to debris flow disaster prevention and reduction.[Method] Based on the reported debris flow cases and corresponding rainfall data in the study area, the quantitative evaluation model of potential debris flow risk in Bailong River Basin is constructed by analyzing the key geological environmental conditions and their relationship, and two kinds of critical discrimination models of debris flow risk level are proposed.[Results]The results show that:(1) The dynamic quantitative calculation model of debris flow risk degree with debris flow activity scale, average gradient of gully bed, watershed cutting density and unstable gully bed ratio can be used as judgment factors to quickly and accurately predict the risk degree of debris flow under different engineering scenarios and rainfall frequencies in the future; (2) The topographic conditions affecting the occurrence of rainfall type debris flow are composed of watershed area, slope area ratio of 10 °-40 °, average longitudinal ratio of gully bed, etc; the rainfall conditions are mainly composed of 24 h cumulative rainfall before the outbreak of debris flow, 1 h rainfall or 10min rainfall triggering debris flow, etc; (3) Based on the risk calculation results of 30 typical debris flow gullies, the critical discrimination value of debris flow risk is obtained, and the 1h prediction model and 10min prediction model of potential debris flow risk of rainfall type are proposed. Among them, the prediction accuracy of debris flow above high risk of class I model is greater than 87.5%, the prediction accuracy of debris flow above medium risk of class II model is greater than 80%, and the verification accuracy of the two prediction models is 83.3%.[Conclusions]The research results provide technical support for the accurate early warning and prediction of debris flow, and have a certain reference significance for the establishment of small and medium-sized debris flow real-time early warning system.

    • Reviews
    • QIN Xuwen, LU Cheng, WANG Pingkang, LIANG Qianyong

      2022,49(3):749-769, DOI: 10.12029/gc20220306

      Abstract:

      This paper is the result of marine hydrates exploration engineering.[Objective] The China Geological Survey successfully carried out two NGH production tests in the Shenhu area in the northern South China Sea (SCS) in 2017 and 2020, setting multiple world records, such as the longest gas production time, the highest total gas production, and the highest average daily gas production. Understanding and mastering the phase transition and seepage mechanism of natural gas hydrate reservoir exploitation in the SCS will help to further reveal the decomposition mechanism, production law, and production increase mechanism of this type of hydrate, and provide a theoretical basis for large- scale and efficient exploitation of hydrate resources in China sea.[Methods] As suggested by the in-depth research on the two production tests, key factors that restrict the gas production efficiency of hydrate dissociation include reservoir structure characterization, hydrate phase transition, multiphase seepage and permeability enhancement, and the simulation and regulation of production capacity, among which the hydrate phase transition and seepage mechanism are crucial.[Results] Study results reveal that the hydrate phase transition in the SCS is characterized by low dissociation temperature, is prone to produce secondary hydrates in the reservoirs, and is a complex process under the combined effects of the seepage, stress, temperature, and chemical fields. The multiphase seepage is controlled by multiple factors such as the physical properties of unconsolidated reservoirs, the hydrate phase transition, and exploitation methods and is characterized by strong methane adsorption, abrupt changes in absolute permeability, and the weak flow capacity of gas. To ensure the long-term, stable, and efficient NGHs exploitation in the SCS, it is necessary to further enhance the reservoir seepage capacity and increase gas production through secondary reservoir stimulation based on initial reservoir stimulation.[Conclusions] With the constant progress in the NGHs industrialization, great efforts should be made to tackle the difficulties, such as determining the micro-change in temperature and pressure, the response mechanisms of material-energy exchange, the methods for efficient NGH dissociation, and the boundary conditions for the formation of secondary hydrates in the large-scale, long-term gas production.

    • YAN Yuchen, YANG Zhongfang, YU Tao

      2022,49(3):770-788, DOI: 10.12029/gc20220307

      Abstract:

      This paper is the result of environmental geological survey engineering.[Objective]In recent years, ecological and environmental pollution caused by microplastics has attracted widespread interest.[Methods]This paper reviews recent progress in research on the sources and hazards of microplastics and detection and treatment technologies investigated in a large number of studies.[Results](1) The primary sources of microplastics in soil are the cracking of agricultural land film without efficient recycling, use of sewage sludge containing microplastics in agricultural production activities, and settling of microplastics from air to surfaces; (2) Microplastics in soil can adsorb heavy metals, antibiotics, and other pollutants, which can change the pH, bulk density, and physical and chemical properties of soil, affect the development of earthworms and other soil animals, and reduce the activities of crucial microorganisms involved in the soil nutrient cycle, thereby harming the soil environment; (3) No unified technical standard for microplastic separation and detection is currently available. Visual inspection and spectroscopic and thermal analysis techniques are the main methods for detecting microplastics.[Conclusions] Microplastics in soil prese nt varied levels of risk to the environment and health of animals and plants and threaten human health through the food chain. Future research can focus on blocking the sources of soil microplastics, the pollution mechanism of soil microplastics and heavy metal compound pollution, and innovations in soil microplastic detection technologies.

    • XU Xuesheng, LUO Jianlan, HUANG Fengqiu, WANG Huanhuan, XIA Xueqi, LU Jiang, ZHANG Zihu, ZHU Lifen

      2022,49(3):789-801, DOI: 10.12029/gc20220308

      Abstract:

      This paper is the result of agricultural geological survey engineering.[Objective] Natural selenium (Se)-enriched agricultural products is the safest and most effective way for human Se uptake. The Serich agriculture and Se- rich characteristic towns, which should be established based on natural Se- rich land, have become the pillars of emerging industries for poverty alleviation and rural revitalization. Their planning and construction should be based on the quality evaluation of Se-rich land, but there is a lack of the method for this evaluation.[Methods] Taking Xintian County as an example, a new system of Se-rich arable land quality evaluation was established, which was composed of the evaluation of land fertility, economic quality, and ecological environment. The evaluation system was based on the development potential, utilization value, and restriction conditions of the arable land. Additionally, this paper carried out a comprehensive evaluation of the natural, environmental, and economic attributes, based on the results of Comprehensive Survey of Se- enriched Soil Geochemistry and National Land Survey in Xinxu Town of Xintian County.[Results] The evaluation results are coincident with the quality of agricultural products and Se- rich degree, which reflected the development conditions and the potential of arable land resources.[Conclusions] The above- mentioned evaluation system can guide the development and utilization of Se- rich arable land, and can be used for the planning of Se-rich land resources and related industry.

    • DU Lei, WEN Huaguo, LUO Lianchao, DONG Junling, WEN Longbin, YOU Yaxian, WANG Qiyu

      2022,49(3):802-821, DOI: 10.12029/gc20220309

      Abstract:

      This paper is the result of hydrogeological and environmental geological survey engineering.[Objective] Terrestrial hydrothermal spring travertine, as a common terrestrial carbonate sediment/rock in volcanic and geothermal areas, is widely used to restore paleoenvironment, but the proxy indicators that can reflect paleoclimate information are mostly controlled by complex external conditions. The extraction of paleoclimate information from hot spring travertine requires further research.[Methods] This paper summarizes the current successful cases of hydrothermal travertine in reconstructing paleoclimate information, and sorts out various climatic and non- climatic influencing factors related to the deposition of hydrothermal travertine.[Results] The authors believe that C- O isotopes, major and trace elements are more feasible for the selection of palaeoclimate restoration proxies for hydrothermal travertine. The palynological data can be used as corroborative information due to the limitation of sporopollen preservation, and can be used in conjunction with other climate proxies. indicators to test whether the palaeoclimate significance is correct or not. At the same time, it is necessary to compare various climatic proxies in thermal spring travertine with relatively mature paleoclimate research methods such as biostratigraphy, ice cores, stalagmites, etc., so that various paleoclimate proxies can be verified with each other, so as to better obtain the information on the medieval climate of the hot spring travertine.[Conclusion] It is feasible to extract and restore reliable paleoclimate information by using various climatic proxies in hot spring travertine.

    • Research Articles
    • ZHANG Hongxin, YU Shaowen, ZHANG Yanpeng, CHEN Wen, LI Qinghua, LIU Huaiqing, ZHANG Qingyu

      2022,49(3):822-833, DOI: 10.12029/gc20220310

      Abstract:

      This paper is the result of hydrogeological survey engineering.[Objective] The purpose of this study is to uncover the spatial-temporal distribution, genesis, and environmental impacts of shallow acidic groundwater in the Fangchenggang area.[Methods] In-situ pH values of shallow groundwater were determined in the study area during 2013 to 2015, including 214 samples in the dry season and 168 samples in the wet season. Spatial and temporal distribution, genesis, and ecological influences of the pH values were discussed.[Results] Results show that the acidic groundwater samples (pH < 6.5) account for 79.3% and 64.3%, respectively, in the wet and dry seasons. In general, pH values in the wet season are lower than in the dry season. Values are generally lower in the low mountain areas (pH 5.0-5.5, mean 5.18, n=4) relative to the hillys (pH mostly 5.0- 6.5, mean 5.97, n=202), and the plain areas (pH typically 6.5- 8.5, mean 6.77, n=8).[Conclusions] Occurrence of acidic shallow groundwater can be contributed primarily to the acid rain, and partly to the acidic unsaturated zone, and oxidation of sulfide minerals. Accordingly, seasonal changes of acidic rain should principally responsible for the spatial variations of groundwater pHs. By contrast, however, tides could increase groundwater pH values in the Jiangping area. Acidic groundwater threatens safe drinking water supply, because only 20.6% samples in the dry season having pHs within the drinking water standard thresholds. Also, it may promote release of some harmful elements from aquifer sediments, and erode underground pipe networks and building pile foundations. In addition, due to discharge, acidic groundwater could influence surface water environment and surface ecosystems. This study contributes to water resources management in the study area.

    • SUN Qifa, YANG Ke, SUN Zhuo'an, JIA Lin'gang, TIAN Hui, GUO Xiaodong, LI Xuguang, ZHU Wei

      2022,49(3):834-848, DOI: 10.12029/gc20220311

      Abstract:

      This paper is the result of hydrogeological and environ mental survey engineering.[Objective] In order to find out the characteristics and evolution of groundwater in Changchun new area and support the construction of northeast old industrial base.[Methods]Based on the investigation and sampling, this paper makes full use of the previous achievements and data, and applies SPSS analysis software and groundwater pollution analysis software, through the analysis of the geological conditions, the spatial distribution characteristics of hydrochemical parameters, the chemical types of groundwater and the chemical causes of groundwater in Changchun new area, a series of results are obtained.[Results]The groundwater in Changchun new area has high hardness and mineralization, HCO3 is dominant in the ions of groundwater, and the absolute mass concentration of Ca2+、Cl-、O42-、Na+ is relatively high; the mass concentration of pH,H2SiO3、Sr,TDS,Mg2+,HCO3 is relatively stable; the ions of groundwater are mainly HCO3 and Ca2+; Na+ and K+ are from the dissolution of rock salt and siliceous rock; Ca2+ and Mg2+ are mainly from carbonate dissolution of salt.The quality of groundwater in the area can be divided into four grades, among which class V water is not evaluated.[Conclusions] In general, class I water accounts for 7.50%, class II water 32.10%, class III water 20.80%, class IV water 39.60%. More than 60.4% of the groundwater is in good condition.

    • ZHOU Changsong, ZOU Shengzhang, ZHU Danni, LIN Yongsheng, WANG Jia, FAN Lianjie, LI Jun, LAN Funing, LI Yanqing, DENG Rixin, MIAO Xiongyi

      2022,49(3):849-859, DOI: 10.12029/gc20220312

      Abstract:

      This paper is the result of hydrogeological survey engineering.[Objective]In recent years, the drinking water health issues has been taken due to the improvement of living standards. Finding and developing high- quality groundwater with high- level minerals (e.g. H2SiO3) has become the key step in improving human health.[Methods]The hydrogeological survey and groundwater pollution survey were carried out in the Zhaojue County, and the spatial distributions of H2SiO3-rich groundwater, hydrogeochemical components characteristics and factors were revealed.[Results] The main results including:(1)The groundwater with H2SiO3 (≥ 25mg/L) was identified as the low salinity and alkaline water, which distributed in the six areas with the basement rocks of basalt. The H2SiO3 concentration was generally 25.74-46.04 mg/L, pH level was generally 7.4- 8.58, and TDS level is generally 49.4- 333 mg/L;(2)The H2SiO3- rich groundwater of study area was characterized by the low mineralization while the main hydrochemical types of groundwater are HCO3- Ca·Mg and HCO3- Ca;(3) The H2SiO3- rich groundwater was influenced by the water- rock interactions, the distribution range and solubility of silicate minerals, the development of surrounding rock fissures, and water conservation and recharge conditions in the county, among which the water- rock interactions play a critical role; (4) It is necessary to further reveal the main factors affecting the distribution and migration of H2SiO3 in groundwater in the subsequent development and utilization process.[Conclusions]The results can provide a basis for the development of mineral water industry and the construction of urban and rural high-quality water sources in Zhaojue area.

    • CHEN Xing, WU Kaibin, WANG Jun, HUANG Jianguo, CHEN Jun, YANG Zhen, DENG Guibiao, LIAO Zhumin, BAI Peirong

      2022,49(3):860-879, DOI: 10.12029/gc20220313

      Abstract:

      This paper is the result of agricultural geochemical survey engineering.[Objective]The research aimed to provide a scientific basis for the rational use of soil nutrients in agricultural production, adjustment of agricultural structure and improvement of land use value in Renhuai.[Methods]Total and available nitrogen (phosphorus and potassium) content and organic matter content of 5,486 topsoil samples were obtained using inductively coupled plasma emission spectrometry, volumetric method, and potentiometric method. Their geochemical characteristics and influencing factors were systematically studied.[Results]The average values of nitrogen, phosphorus, potassium, organic matter, available nitrogen, rapidly available phosphorus, and rapidly available potassium were 1.74 g/kg, 0.75 g/kg, 19.90 g/kg, 30.90 g/kg, 100.28 mg/kg, 10.40 mg/kg, and 101.03 mg/kg, respectively. The contents and distributions of nitrogen, available nitrogen, phosphorus, potassium, and organic matter were closely related to the stratum, whereas those of rapidly available phosphorus and rapidly available potassium were not. Cultivated land in Renhuai had a relatively high soil fertility rating, which was mainly dominated by relatively rich soil grades, with the share of relatively rich and rich grades reaching 57.6%. Rich nitrogen, phosphorus, and potassium levels were found, along with medium available nitrogen and organic matter levels. However, rapidly available phosphorus and rapidly available potassium were at deficient levels.[Conclusions]The content and distribution of soil nutrients in cultivated land are not only affected by natural factors such as geological background, soil type, altitude, pH, and soil depth, but also related to human activities, such as land use patterns.

    • ZHANG Yixuan, BAI Chenyang, LIU Yujia, YANG Hailin, LIVIO Ruffine, LAI Yong, LU Hailong

      2022,49(3):880-900, DOI: 10.12029/gc20220314

      Abstract:

      This paper is the result of environmental geological survey engineering.[Objective]In the last glacial period, global climate was characterized by rapid, large-scale temperature cycles on a millennial scale. Such climate changes could be recorded in many geological materials such as ice cores, deep-sea sediments, Chinese loess, and cave stalagmites. The Black Sea is located in the transition zone between the North Atlantic and East Asian monsoon regions and has formed representative sedimentary records. This article is aimed at establishing the connections between the regional environmental changes of the Black Sea and the climate changes in the North Atlantic and East Asian monsoon area through the study of the sedimentary sequences of the Black Sea.[Methods]In this study, a 22.0 m core sample taken from Core GAS-CS12 in the northern slope of the Danube Canyon in the northwest of the Black Sea was analyzed for particle size, mineral composition, major elements, organic carbon, total nitrogen, and carbon and nitrogen isotopes.[Results]It was revealed that the core sediments of this section were deposited in the"Neoeuxine"lacustrine stage in the middle and late period of the last glacial period, and can be divided into 5 sedimentary units, corresponding to H4, H3, and H1 climate change events in the North Atlantic, the Last Glacial Maximum (LGM), and Bolling- Allerod climate warming event.[Conclusions]The connections between the sedimentary sequences and regional environmental changes of the Black Sea with the climate changes in the North Atlantic and East Asian monsoon area were established and this paper also confirmed that the millennium-scale climate changes of the last glacial period were highly consistent in the North Atlantic, East Asian monsoon area and their transition zones.

    • ZHANG Yufen, LI Chang'an, XIONG Deqiang, ZHANG Dai, HU Xulong

      2022,49(3):901-911, DOI: 10.12029/gc20220315

      Abstract:

      This paper is result of environmental geological survey engineering.[Objective]The representative dust deposit, the Wushan Loess located in China's northern subtropical river valleys, is a significant indication of environment near the Three Gorges region.[Methods]In this study, we collected samples from the Wushan Loess and analyzed rare earth elementary composition to discuss paleoclimatic significance of Wushan loess.[Results]Our new data show the four following implications. (1) The REE contents in each sample changes synchronously with little difference. The contents of LREE is much higher than that of HREE in each sample, suggesting the enrichment in LREE and loss in HREE. (2) The increasing of ∑REE with age in Wushan Loess is probably related to the strength of weathering the in Wushan Loess. (3) For samples from various depth, REE distribution patterns, δCe, δEu, La/Yb, Gd/Yb and ΣREE do not change significantly with depth. (4) The REE distribution patterns of all samples display negative slope, steep La-Eu curves and flat Eu-Lu curves, which suggests that certain differentiation between LREE and HREE has occurred. (5) The δEu values of Wushan Loess distributed within the interval of 0-1 on the vertical axis show obvious negative Eu anomalies andstable δCe values around 1. This implies that sediment in the upper Yangtze River did not suffer strong weathering in the period of Wushan Loess.[Conclusions]Wushan Loess have not been through intense weathering effect, the climate of its region while accumulation was colder and drier in the later period than it was in the earlier period, and no obvious change has been found in the source of its materials during the accumulation process.

    • WEI Rongzhu, ZHUANG Qitian, YAN Jiyuan, WEI Yunfeng, DU Yanwei, FAN Junhui

      2022,49(3):912-928, DOI: 10.12029/gc20220316

      Abstract:

      This paper is the result of environmental geological survey engineering.[Objective] Jinzhong Basin is located in the middle of the Fen-Wei Fault Depression Basins, in which the maximum thickness of the Cenozoic sedimentary layer exceeds 3800m. The establishment of the precise stratigraphic framework and the high-resolution sedimentary sequence of Jinzhong Basin is vital to understanding the evolution of the Fen-Wei Fault Depression Basins and the climate changes in North China.[Methods] In this paper, the chronology and sedimentology methods were used on the drill cores of the late Cenozoic standard borehole ZK01 (870.5m in depth) in the northeast of the Jinzhong Basin.[Results] The loose sediments in the borehole ZK01 were divided into 6 lithological formations. By means of magnetostratigraphy, the stratigraphic time frame was built with 13 normal polarity periods and 12 reverse polarity periods for the first time. The oldest Cenozoic sediments at the bottom of Jinzhong Basin is approximately 8Ma, moving the starting time of Jinzhong Basin activity forward about 3 Ma, from early Pliocene as previously believed to late Miocene. The late Cenozoic strata in this region are divided into Neogene Miocene Baodean Stage (N14) and Bahean stage (N15), Pliocene Gaozhuangian Stage (N21) and Mazegouan Stage (N222), Quaternary lower Pleistocene Nihewanian Stage(Qp1), middle Pleistocene, upper Pleistocene, and Holocene.[Conclusions] Tectonic activity and climate change are the main controlling factors of the sedimentary environment in the basin, which results in two periods of large- scale lake development in the early Pliocene and middle- late early Pleistocene. In the early- middle Holocene, i.e., pre- Qin period (circa 2.5ka ago), rivers and lakes were in the coexistence stage in the basin; In the late Holocene (circa 2.5ka after), lakes atrophied, and rivers dilated; Then the lakes vanished in Ming and Qing period. Climate change and the impact of human activities are the main reasons for the eventual disappearance of the lakes in the basin.

    • HUANG Lishan, HOU Yijun, CHEN Yuanrong, JING Rongzhong, WANG Jianchao, ZHAO Yi, LI Xuebiao, PEI Chao, ZENG Youqiang, ZENG Hui

      2022,49(3):929-942, DOI: 10.12029/gc20220317

      Abstract:

      This paper is the result of hydrogeological survey engineering.[Objective]The detection of concealed fault structure in the city and its surrounding areas has an important impact on urban construction and economic development, which has attracted people's attention. According to the geological background and human conditions of the city, the key to the rapid and accurate location of concealed fault is to adopt appropriate methods, which must have the characteristics of rapid economy, green environmental protection and strong anti- interference ability.[Methods]Taking Lingui District of Guilin city as an example, in order to quickly and accurately locate the concealed fault F1 covered by the quaternary system, according to the geological background and the characteristics of the surface landscape of the District, a comprehensive geophysical and geochemical exploration method, such as CSAMT, soil mercury gas measurement, radon gas measurement, is adopted.[Results] It is found that the low resistivity anomaly is highly consistent with the high value anomaly of soil mercury gas and radon gas, It is speculated that the location of the multi method abnormal coincidence is the location of the concealed fault, and through drilling verification, the concealed fault structure and rich groundwater are exposed, which provides a basis for the search and development of deep geothermal water in this area.[Conclusions]It is obvious that CSAMT, soil mercury gas measurement and radon gas measurement are the technical combination to realize the rapid and accurate location of concealed faults in Guilin and its surrounding areas, and also provide reference for the detection of concealed faults in other areas.

    • ZHANG Baomin, CHEN Xiaohong, CAI Quansheng, CHEN Lin, ZHANG Guotao, LI Peijun

      2022,49(3):943-955, DOI: 10.2029/gc20220318

      Abstract:

      This paper is the result of oil and gas exploration engineering.[Objective]The differences in mineral composition, gas content and compressibility of shale lithofacies determine the development potential of shale gas. The division and evaluation of shale lithofacies is important to identify the sweet spot for shale gas exploration and development.[Methods]Based on drilling, core analysis, and test data, the comprehensive utilization of geological theory combined with ternary diagram of siliceous mineral, clay minerals, and carbonate mineral content are used to divide the gasbearing shale lithofacies of the Wufeng Formation and the lower part of Longmaxi Formation in Yichang slope of western Hubei province. The dominant lithofacies are also divided combining with the organic carbon content, gas content, and microscopic characteristics. The correlation between the abundance of organic matter, the content of siliceous minerals, the content of clay minerals and the shale gas content are carried out to establish the classification standard of gas- bearing dominant lithofacies of Wufeng- Longmaxi Formation.[Results]The dominant lithofacies in the study area is type II. The type II1 (optimal) dominant lithofacies are mixed siliceous shale facies (S-2) and clay-bearing siliceous shale facies (S-3), located in the first sub-member of Longmaxi Formation and the upper member of Wufeng Formation, with thickness of 6 m. The type II2 dominant lithofacies (suboptimal) is siliceous shale facies (S), located in the lower member of Wufeng Formation, with thickness of 4 m.[Conclusions]The Yichang slope belt and Fuling area have similar vertical evolution sequence of lithofacies, and the dominant lithofacies are both located in the Wufeng Formation and first sub-member of Longmaxi Formation. However, the thickness and quality of same shale lithofacies association are quite different. The subaqueous uplift of western Hunan and Hubei in the Rhuddanian stage is the main reason that caused the thickness and quality of the dominant lithofacies in Yichang area poorer than that in Fuling area.

    • BAI Bowen, PING Jianhua, ZHAO Jichang, YANG Zhenwei, NING Yiwu, XIONG Chaofan

      2022,49(3):956-966, DOI: 10.2029/gc20220319

      Abstract:

      This paper is result of geothermal geological survey engineering[Objective] Geothermal resource in Huaiyang area belongs typical medium- low temperature geothermal resource of subsidence basin. Evaluation of geothermal resources in the Huaiyang area can provide insights into its exploitation and scientific management.[Methods]In this paper, we analyzed the geochemical and isotopes characteristics of geothermal fluids to explore their local geothermal field features and genesis.[Results] The results show that the deep thermal reservoirs are significantly affected by basement structure and faults characteristics. The geothermal gradient is higher (e.g., 3.75℃/100m in the Suzhuang area) along the boundary of faults than the other areas (e.g., 3.5℃/100m). The type of the geothermal fluids are dominated by Cl · HCO3 · SO4-Na, Cl·SO4·HCO3-Na and Cl·SO4-Na. The main cation of the geothermal fluid is Na+ while the anions variou in types. The geothermal fluids were probably derived from the atmospheric "ancient water" of the Funiu Mountain in the western Henan province before 1952, with relatively weak rock-fluid reaction.[Conclusions]The major exploited geothermal reservoirs are placed at the Neogene Minghuazhen and Guantao Formations. The geothermal resources are mainly used for heating feeding, etc., which has greatly improved the local economy, Contribute to the realization of the "dual carbon" goal in the region.

    • QI Zexue, WANG Shengbin, WANG Qiangmin, XIAO Yong, WEN Chuan

      2022,49(3):967-978, DOI: 10.2029/gc20220320

      Abstract:

      This peper is the result of hydrogeological survey engineering.[Objective] Golmud is a rising city on the Qinghai- Tibet Plateau located on the southern edge of the Qaidam Basin. With the construction of various industrial parks and the establishment of the largest potash production base in China, the important role of groundwater resources has become more prominent. For the operation of industrial and mining enterprises and potash production bases, it is very important to find out the amount of underground water resources.[Methods] Based on data collection, dynamic long view, borehole pumping test, etc., the regional groundwater natural resources and allowable exploitation were evaluated by using the recharge sum method, section runoff method, excretion sum method and combined numerical simulation method, etc.[Results] The amount of groundwater natural resources in the alluvial fan of Golmud River is 199.8×104 m3/d, and the allowable exploitation amount is 100×104 m3/d.[Conclusion] Millions of tons of underground water sources exist in Golmud area. To ensure an adequate recharge of groundwater, the condition for sustainable and stable exploitation is that the planned exploitation of six water sources (built/under construction/planning) reaches one million tons. Finally, a million- ton groundwater source with B + C groundwater reserves of 100×104m3/d is submitted.

    • YIN Dechao, QI Xiaofan, WANG Yushan, XU Rongzhen, AN Yonghui, WANG Xuqing, GENG Hongjie

      2022,49(3):979-992, DOI: 10.2029/gc20220321

      Abstract:

      This peper is the result of environmental geological survry engineering.[Objective] Baiyangdian Lake(BYD Lake)is the main ecological function area of Xiong'an New Area. In order to provide support for ecological restoration and protection of BYD Lake, we conducted a comprehensive survey on the environmental quality of the surface sediments in BYD Lake.[Methods] We collected 484 sets of surface sediment samples from Baiyangdian wetland, identified the geochemical characteristics of heavy metals in surface sediments of Baiyangdian lake, and used multiple methods such as geo- accumulation index method and potential ecological risk index method to evaluate the ecological risk of heavy metals.[Results] The results indicate that the average content of most heavy metal elements in the surface sediments of BYD Lake is significantly higher than the soil background value in Hebei Province. The entrance of Fuhe river and Baigou river are the main rich areas of heavy metal elements, rivers are the main sources of heavy metals in the surface sediments of BYD Lake. The distribution area of clean and pollution-free grade is 144.54 km2, accounting for 96.68% of the total surface sediment distribution area. The pollution degree of each heavy metal can be ranked as Cd > Cu > Hg > Pb > Zn > Ni > Cr > As. The pollution degree of Cd is mainly moderate, the pollution degree of Cu is mainly light and clean, and the pollution degrees of other elements are mainly clean and pollution-free. The potential ecological risk of heavy metals in the surface sediments of BYD Lake is mainly mild and moderate, and the potential ecological risk level of heavy metals near the river entrance is higher than that of other areas. The potential ecological risk levels can be ranked as Nanliuzhuang > Shaochedian > Xiaobaiyangdian > Wangjiazhai > Zaozhadian > Laowangdian > Chiyudian > Fanyudian.[Conclusions] The environmental quality of the surface sediments in BYD Lake is generally good, with heavy metals exceeding the standard in some areas. The environmental quality of surface sediments in Baiyangdian is generally good. There are potential ecological risks of heavy metal pollution in Nanliuzhuang and other areas, and Cd is the main pollution element.

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    Volume 49,2022 Issue 3
    • LI Xu-bing , ZHAO Can, LIU An, WEI Kai, LI Jitao

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

      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.

    • 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:

      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.

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

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

      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.

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

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

      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.

    • 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:

      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”.

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

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

      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.

    • 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:

      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.

    • 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:

      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.

    • WANG Lei, LONG Wen-guo, ZHOU Dai

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

      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.

    • WANG Kai-ming

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

      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.

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

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

      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.

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

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

      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.

    • 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:

      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.

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

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

      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.

    • 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:

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

    • 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:

      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.

    • 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:

      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.

    • XU Tong1, PEI Xian-zhi1, 2, LI Rui-bao1, 2, LI Zuo-chen1, 2, PEI Lei3, LIU Cheng-jun1, CHEN You-xin1, WANG Xiao-wei1, YANG Jie1, HU Nan1

      2013,40(6):1777-1792, DOI:

      Abstract:

      Abstract: Zhangyangou bimodal volcanic rocks are located in Hengxianhe area,Sanchazi-Lueyang segment of Mian-Lue tectonic zone. The bimodal volcanic rocks consist of metamorphosed basic volcanic rocks and metamorphosed acid-intermediate rocks in close association, and the protoliths are sub-alkaline basalt and sub-alkaline rhyolitic-dacite. On account of the higher REE concentrations in basalt than in rhyolitic-dacite, the authors hold that the origin of rhyolitic-dacite was partial melting of the crustal material rather than the fractional crystallization of the basaltic magma. Basic volcanic rocks show the intraplate geochemical characteristics such as high Zr concentrations and Zr/Y ratios, and their marks of arc result from the hybridism of the crustal material. The result of U-Pb isotope dating by means of Laser Ablation Inductively Coupled Plasma Mass Spectrometry makes it clear that the formation age of the rhyolite is (728±10) Ma(n=4, MSWD=0.14). Combined with the regional geological background, the authors consider that Zhangyangou bimodal volcanic rocks were formed in a continental rift environment under the crust extensional mechanism. The formation of Zhangyangou bimodal volcanic rocks heralded the opening of Neoproterozoic Ocean. This new achievement is of important significance both for the further study of the evolution of Mian-Lue tectonic zone and the breakup of Rodinia supercontinent and other continents on the north margin of the Yangtze block.

    • DONG Lian-hui1, WANG Ke-zhuo2, ZHU Zhi-xin2, ZHAO Tong-yang2, XU Shi-qi2, ZHENG Jia-xing2

      2013,40(5):1552-1568, DOI:

      Abstract:

      Abstract:Located in the convergence zone of India plate, Tarim-Sino-Korean paleoplate and Siberia ancient plate, Xinjiang has complicated geological structure. With an analysis of the characteristics of large deformation as a starting point, this paper comprehensively summed up such characteristics of the large-scale deformation structure as its type, size, pattern, material composition, structural order and deformation stage, discussed the control role of the large-scale deformation structure over stratigraphic framework, magmatic activities, metamorphism and deformation, regional tectonic evolution and metallogenesis, and divided the tectonics into 34 large deformation structures. The relationship between the evolution of large-scale deformation structure and the mineralization was tentatively investigated.

    • XU Zhi-qin1, WANG Qing2, ZENG Ling-sen1, LIANG Feng-hua1, LI Hua-qi1, QI Xue-xiang1, CAI Zhi-hui1, LI Zong-hai1, CAO Hui1

      2013,40(3):671-680, DOI:

      Abstract:

      Abstract:The Greater Himalayan Complex (GHC) , as the metamorphic core of the Himalayan orogen, shows a “hot” collisional orogen characterized by high-grade (up to granulite facies) metamorphic rocks exhumed from the middle-lower crust, widespread migmatites from extensive anatectic processes and high-temperature ductile deformation. A three-dimensional tectonic model for extrusion of the GHC has been proposed based on the discovery of widespread orogen-parallel ductile extension. It is suggested that extrusion dynamic processes of the GHC are as follows: (1) partial melting in 45-36Ma resulting in the weak and hot middle crust, (2) orogen-parallel gravitational collapse in 28-26Ma, (3) ductile thrusting since > 26 Ma and (4) ductile extrusion resulting from the formation of MCT and STD during 23-17Ma .

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