• 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 4
      In Focus
    • LI Ziying, LIU Wusheng, LI Weitao, LI Xide, QIN Mingkuan, CAI Yuqi, ZHANG Yunlong, HE Sheng, WU Qubo, QIU Linfei, LIU Chiheng, ZHU Pengfei, JI Hongwei, GUO Jian

      2022,49(4):1009-1047, DOI: 10.12029/gc20220401

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective]The Hadatu uranium deposit is a giant uranium deposit that occurs in the upper part of the early Cretaceous Saihan Formation in the Erlian Basin. Unlike traditional sandstone-type uranium deposits, the Hadatu uranium orebody exhibits stratiform and tabular shape, and the ore-controlling grey sandstone body is surrounded by red mottled oxidized sandstone. It is difficult to explain the genesis of the Hadatu uranium deposit with the traditional infiltration (phreatic and interlayer oxidization-reduction) metallogenic theory of sandstone-type uranium deposits. Therefore, identification of the ore genesis and ore-controlling factors of the Hadatu uranium deposit becomes very significant to the innovations of metallogenic theory for sandstone-type uranium deposits and to uranium prospecting in red mottled sandstone.
      [Methods]Both fieldwork and lab analysis were conducted, and macro-and micro-observations were made. Adopted methods include field observations, regional geology, tectonics, sedimentology, petrology, mineralogy, geochemistry (i.e. element, organic and isotopic analysis), seismic interpretation and uranium metallogenic studies, etc.
      [Results]The signatures of the orebody, ore-controlling grey sandstone body and the metallogenic characteristics of the Hadatu uranium deposit are clarified. It is evidenced that the upper part of the red mottled Saihan Formation, Erlian Formation and the Irdin Manha Formation are of the primary oxidization origin, whereas the ore-controlling grey sandstone body in the ore-bearing Saihan Formation is of epigenetic origin, resulted from secondary reduction through deep-seated reducing fluids that are mainly controlled by the fault structures and pertinent river channels or unconformities. Based on the analysis of the ore-forming uranium source, fluids deriving from the depth and their transportation and precipitation of the uranium, this paper demonstrates a new exudative uranium metallogeny. The authors propose that Hadatu sandstone-type uranium deposit occurs predominantly by exudative uranium metallogeny and correspondingly establishes the exudative uranium metallogenic model.
      [Conclusions]The exudative uranium metallogeny, as a new kind of uranium metallogeny in red mottled sandstone-type uranium deposits, has been established. The new methods to identify uranium mineralization in red mottled sandstone have been concluded, i.e. "combining the information of the upper red and lower black sedimentary formation, connecting pathways of the upper red formation with lower black one, finding grey sandstone body in red mottled formation and uranium in the grey sandstone body". The perspective of sandstone-type uranium deposits in red mottled sedimentary formation has been pointed out and new prospecting area from margins to the center of the basin and from near surface to deeper strata have been expanded.
      Highlights: Illustrated that the ore-controlling grey sandstone body is of epigenetic origin, resulted from secondary reduction of deep-seated reducing fluids. The authors also propose a new exudative uranium metallogeny in red mottled sandstone and establishes the exudative uranium metallogenic model for Hadatu uranium deposit. Furthermore, the new exploration and evaluation methods to identify uranium mineralization in red mottled red sandstone have been concluded.

    • FU Yujia, TAN Changhai, LIU Xiaohuang, SUN Xingli, YUAN Zemin, ZHENG Yiwen

      2022,49(4):1048-1063, DOI: 10.12029/gc20220402

      Abstract:

      This paper is the result of natural resource survey engineering.
      [Objective]At present, there are many problems, such as the different connotations of natural resources, the differences in classification, the inconsistency in data acquisition, and the overlapping of resources in spatial management caused by the different departments of resource management. We need to solve above-mentioned problems to investigate the situation of resources in China to recognize the variation laws of resource, and to manage utilization of territory.
      [Methods]This paper adopted the method of literature review to sort out the definition, classification and observation and monitoring index of natural resources.
      [Results](1) We clarified the conception of natural resources under the observation and monitoring system which were resources that could generate value through production in natural state or unprocessed state. They were divided into three categories:Climatic resources, surface cover resources, and groundwater resources; (2) We summarized the object, content and observation method of the comprehensive observation and monitoring of natural resources; (3) We analyzed the role of natural resource observation and monitoring in resources assets management and ecological environment restoration with examples.
      [Conclusions]Based on the analysis above, this paper pointed out that natural resources observation and monitoring were indispensable technical means to study the interaction between resources, resources and environment, resource asset management, and ecological environment restoration.
      Highlights: (1) Clarify the definition of natural resources and solve the problem of inconsistencies in the management, classification, and data access of natural resources; (2) The content and indicators of natural resource observation and monitoring are analyzed, combined with the "four-in-one" detection technology of systematic survey, observation experiment, prediction simulation, monitoring, and evaluation, effectively grasping the natural resource base, carrying out resource asset management, studying the interrelationship between resources, resources, and the environment, and playing a role in land planning and governance.

    • LIANG Shuai, DAI Huimin, LIU Guodong, ZHAI Furong, LIU Kai, HAN Xiaomeng, SONG Yunhong, ZHAO Jun, ZHANG Zhehuan

      2022,49(4):1064-1074, DOI: 10.12029/gc20220403

      Abstract:

      This paper is the result of ecological geological survey engineering.
      [Objective]The natural endowment, genetic source, ecological environment effect and human health evaluation of soil selenium in typical black soil distribution areas are the research focus of healthy geology, a quantitative study on the migration and accumulation of selenium in the soil-crop-human system in the Shuangyang River Basin was carried out. The development of selenium-rich agricultural products in black soil and the prevention and control of endemic diseases are of great significance.
      [Methods]The selenium content of parent material, soil, atmospheric dust, irrigation water, crop seeds and human hair was determined, and the results were statistically analyzed and evaluated by GIS and SPSS software.
      [Results]The selenium-enriched land is 46.4 km2, mainly distributed along the Shuangyang River and its tributaries; the selenium is largely caused by human beings, mainly from atmospheric dust supplementation with an input flux of 0.21-1.47kg/km2 · a. The mean selenium contents of soil, soybean, rice, corn and human hair are 0.305 mg/kg, 0.0352 mg/kg, 0.0287 mg/kg, 0.0198 mg/kg and 0.145 mg/kg. The enrichment coefficient of selenium from crops to soil (0.120) is much less than 1, and the enrichment coefficient of selenium from human hair to crops (4.834) is greater than 1, indicating that human hair has a strong concentration and amplification effect on selenium. The migration and accumulation of selenium in the soil-crop-human system shows a "V"-shaped pattern.
      [Conclusions]In general, the selenium content in the soil is sufficient or rich with no potential environmental risk. Soybean and rice are rich in selenium, accounting for 28.4% and 9.4%, with no selenium exceeding the standard and poisoning in organisms. The content of selenium in human hair is significantly lower than the reference value of 0.20-0.60 mg/kg, indicating that the human body is in a state of selenium deficiency, and the selenium content tends to decrease with age. There may be certain health risks, which should arouse the attention of local relevant departments.
      Highlights: Migration and accumulation of selenium in soil-crop-human system of typical black soil area were studied based on systematic ecological geochemical data and statistical analysis principle, which provided scientific basis for the development of selenium-rich agricultural products and local disease control.

    • ZHOU Pan, YE Siyuan, WANG Jin, YU Changbin, YUAN Hongming, PEI Lixin, DING Xigui, YANG Juan, HANS Brix

      2022,49(4):1075-1087, DOI: 10.12029/gc20220404

      Abstract:

      This paper is the result of environmental geological survey engineering.
      [Objective]As a refractory soil protein secreted by arbuscular mycorrhizal fungi (AMF), glomalin-related soil protein (GRSP) is an important component of long-term carbon storage and widely distributed in sediment of terrestrial ecosystem. The distribution of GRSP in coastal wetlands is still not well documented. In this study, the spatial distribution of GRSP in the sediments of the typical wetlands along the Bohai Sea coasts in China were characterized, and the distribution of GRSP in different wetland habitats and its relation to sediment weathering in wetlands were discussed.
      [Methods] Particle size, major elements and GRSPs of 166 surface samples (0-5 cm) and 4 sediment cores (~35 cm long) in the wetlands of the Liaohe delta (LHD), Beidagang Lake(BDG)and Yellow River delta (YRD) were tested, and the corresponding chemical index of alteration (CIA) was calculated.
      [Results]The GRSP in surface sediments were significantly affected by the vegetation types, ranged from 0.06 to 11.31 mg/g, with an average of (2.35±0.16) mg/g; The sediments in the three study areas were mainly silty sand and sand, the distribution range of CIA values were 44.79-69.59, some areas reached moderate chemical weathering; The concentrations of GRSP were significantly correlated with CIAs (R=~0.49, p<0.01). In general, CIA increased first with increasing GRSP until the GRSP concentrations reached a certain critical level.
      [Conclusions]The distribution of GRSP concentrations in coastal wetland sediments was affected by habitat differences, and its correlation with CIA indicated that AMF and its metabolites play potential ecological functions during the processes of geological weathering.
      Highlights: The interactions between glomalin-related soil protein and geological processes were revealed; The potential ecological functions of arbuscular mycorrhizal fungi were elucidated.

    • SUN Houyun, SUN Xiaoming, WEI Xiaofeng, CHEN Ziran, LIU Wei, HUANG Xingkai, LI Xia, YIN Zhiqiang, LIU Wenbo

      2022,49(4):1088-1113, DOI: 10.12029/gc20220405

      Abstract:

      This paper is the result of the hydrogeological survey engineering.
      [Objective]The orientation of Chengde City's primary function of ecological environment in Beijing-Tianjin-Hebei Urban Agglomeration is a water conservation area due to its abundant water resource endowment. It is of great significance to clarify the occurrence, spatial variation, and formation mechanism of metasilicate mineral water for the sustainable utilization of water resources and the optimization of water conservation.
      [Methods]Multivariate statistical analysis, rock-wreathing lithogeochemical, hydrogeochemical, and multiple isotopic (δD, δ18O and δ13C) approaches were systematically conducted to identify the influencing factors of the enrichment and spatial variation of metasilicic acid in groundwater in the study area under a water-rock interaction perspective of the Earth's Critical Zone.
      [Results]The results showed that the normal temperature water samples with soluble SiO2 concentrations higher than 30 mg/L accounted for 5.16%, while the average concentration of soluble SiO2 of geothermal water reaches 61.76 mg/L. The enrichment of soluble SiO2 in groundwater was controlled by the rock-weathering desiliconization process and water yield property and transmissivity of geological structures, simultaneously restricted by the recharge of weathering medium acidic substances and hydrochemical formation process in aqueous porous media. The higher the weathering sensitivity of waterbearing media, or the higher the content of easily weathered minerals in exposed strata, the higher the concentration of soluble SiO2 in aquifers tend to obtain. The hypergene silicate rock of the study area was generally in the primary chemical weathering stage that kaolinite, montmorillonite, and illite were formed during the dissolution of feldspar minerals, pyroxene, and other mafic minerals. The mantle-derived CO2, exogenous sulfuric acid, nitric acid generated by mining, artificial and agricultural activities were demonstrated to be jointly involved in the rock weathering process. The metasilicate mineral water and geothermal springs were mostly occurring or exposed in the composite parts of the structure or the intersection of main and secondary faults.
      [Conclusions]The genetic model of metasilicate mineral water in Chengde City can be generalized into three types:Deep circulation leaching of tectonic faults, shallow circulation leaching of weathered fissures, and interlayer pore and fracture-recharge enrichment burial type. The intersection zones of the piedmont wide-gentle valley and the water-transmitting faults in the basalt, pyroclastic rock, terrigenous clastic rock basin with high vegetation coverage, water-thermal conduction fracture zone of intrusive rock, contact zones between the intrusive rocks and surrounding rocks, carbonate rocks and granite, gneiss or terrigenous clastic rocks turn out to be the potential exploitation areas of metasilicate mineral water in the bulk horizons.
      Highlights: (1) The forming mechanism of metasilicate mineral water were clarified under an Earth's Critical Zone perspective based on coupled rock-wreathing lithogeochemical and water-rock interaction hydrogeochemical approaches. (2) The genetic model of metasilicate mineral water, controlling and influencing factors for spatial variation of groundwater soluble SiO2 in Chengde were systematically summarized in this paper.

    • Reviews
    • LI Meina, YIN Ping, DUAN Xiaoyong, DONG Chao, CAO Ke, YANG Lei, CHEN Xuanbo

      2022,49(4):1114-1126, DOI: 10.12029/gc20220406

      Abstract:

      This paper is the result of the environmental and ecological survey engineering.
      [Objective]In the past 20 years, the land type distribution in coastal areas of the Yangtze River Delta has been significantly transformed, highlighting conflicts between coastal zone development and protection.This study examines land use changes and eco-environmental effects in coastal areas of the Yangtze River Delta and seeks to provide a scientific basis for the sustainable use of land resources and environmental protection in the coastal areas.
      [Methods]Automatic supervised classification combined with visual interpretation of remotely sensed images from the Landsat satellite series of the United States and the resource satellite series of China was used to obtain land use classification data for the study area over five periods between 1995 and 2015. The data were analysed to determine the characteristics and trends in land use changes and explore spatial and temporal changes in urban development, reclamation, and eco-environmental effects in typical coastal areas of the Yangtze River Delta.
      [Results]From 1995 to 2015, the typical areas (Nantong, Shanghai, Jiaxing, Ningbo, and Zhoushan) experienced significant changes in land use, with a notable decrease in arable land from 68.8% in 1995 to 55.7% in 2015, whereas urban construction land expanded rapidly, with an average annual increase of 192.8 km2.
      [Conclusions]With rapid urbanisation, the population and energy consumption per unit area increased rapidly, environmental concerns became pronounced, a large area of arable land was converted to construction land, and reclamation caused a rapid decline in coastal wetland areas, resulting in high CO2 and a severe imbalance between the release and absorption of pollutants. The marine environment has been significantly affected by the construction of watersheds and coastal towns, and red tides have occurred frequently in the Yangtze River estuary and adjacent waters in the past 20 years, thereby increasing pressure on the land and marine environment in the study area.
      Highlights: (1) This study examined typical coastal areas of the Yangtze River Delta and used remotely sensed image data of five periods between 1995 and 2015 and performed spatial overlay analysis to identify spatial and temporal evolution characteristics of construction land and reclamation areas. (2) With a focus on human activities, we used a combination of marine environmental indicators to analyse the eco-environmental effects of construction land and reclamation in the course of rapid urbanisation.

    • SHEN Haoyong, LI Jia, WANG Zhiheng, XIE Hao, LIANG Yongping, Yongxin XU, HAN Shuangbao, REN Jianhui, PAN Yaoyun, ZHAO Chunhong, ZHAO Yi

      2022,49(4):1127-1138, DOI: 10.12029/gc20220407

      Abstract:

      This paper is the result of the hydrogeological survey engineering.
      [Objective] As the second largest tributary of the Yellow River, Fenhe River is the largest river in Shanxi Province. However, there is contradiction between the supply and demand of water resources in the basin. The analysis of water resources utilization and ecoenvironment problem is precondition of ecological remediation.
      [Methods]Based on the analysis of water resources characteristics of the Fenhe River Basin and its utilization, this paper systematically summarizes the ecological and environmental problems of the Fenhe River watershed, such as attenuation of runoff, drying up of karst spring and deterioration in water quality.
      [Results]Our result shows that the average amount of water resources in the Fenhe River Basin for multi-year average is 3.359 billion m3, groundwater resources are the main component of the total water resources, which is accounting for 72%. The structure of water supply of water resources has changed greatly due to the impact of comprehensive treatment measures in the Fen River Basin since 2005, such as cross-basin water transfer and groundwater pressure extraction. The water supply ratio of surface water has increased from 30% to 55%, and the water supply ratio of groundwater has been reduced from 62% to 37%. Overall, the utilization of water resources in the Fenhe River Basin is as high as 80%. Excessive exploitation of water resources has caused serious eco-environmental problems such as the cut-off of Fen River, the significant decline in the runoff of the Fen River into the Yellow River and the decline of karst spring flow. The percentage of runoff for Fenhe River enter the Yellow River has attenuated by 63.5% from 1955 to 2018. The main reasons for the attenuation are the decrease in precipitation and the flow attenuation of the karst spring. The total flow of the 8 large karst springs in the Fenhe River Basin has decreased by 69% from 1956 to 2018, and 50% of the large karst springs had dried up in different periods; The water quality of karst springs has been deteriorating seriously, for example, the TSD and SO42- of Jinci Spring and Longzici Spring have been increasing year by year. Coal mining is the main reason for the rapid increase of SO42- in karst springs.
      [Conclusions]Although the inter-basin water transfer project construction has improve some of the eco-environment in the Fenhe River, such as the recovery of Fenhe River to perennial river, and the stopped falling of groundwater level in the basin, and the improvement of the quality of surface water environment, there is serious unbalance between supply and demand for water resources in Fenhe River Basin, finally the trend of deterioration of the ecological environment is still severe.
      Highlights: The characteristics of water resources and the change of water supply structure in Fen River basin in recent are analyzed in the past 15 years; The eco-environment problem of Fenhe River is summarized and their causes are discussed.

    • XIA Riyuan, LU Haiping, CAO Jianwen, ZHAO Liangjie, WANG Zhe, LUAN Song

      2022,49(4):1139-1153, DOI: 10.12029/gc20220408

      Abstract:

      This paper is the result of the hydrogeological survey engineering.
      [Objective] The problems of drought and water shortage in the karst areas of southern China are extremely prominent, the storage and distribution of karst groundwater are complex, and the utilization rate of development is low, based on years of investigation and research work, the characteristics of groundwater resources in the karst area in southern China are systematically summarized, and the countermeasures for water resources protection are studied.
      [Methods]Based on the characteristics of groundwater resources, the types of groundwater systems, the spatial structure of groundwater systems, and the uneven distribution of time and space in the southern karst area, the countermeasures for water resources protection in the southern karst area are proposed.
      [Results]The southern karst area can give full play to the role of groundwater resource security from the following three aspects:One is to grasp the law of groundwater storage and distribution, and play the role of decentralized water supply and emergency water supply. The second is to strengthen the construction of storage projects to solve the problem of unevenly distributed water resources. The third is to establish a sustainable use model of groundwater resources combined with ecological reconstruction and economic development.
      [Conclusions]The groundwater storage conditions in the southern karst area are complex, and there are many types of karst water systems in the surface zone, karst underground rivers and pipeline flow systems, karst large spring systems and scattered discharge groundwater systems, with different scales and different development and utilization. It has superposition in the vertical upward, and the time-space distribution of karst groundwater is seriously uneven; The potential for development and utilization is large. Under the guidance of the earth science system theory, it is necessary to find out the law of the allocation and distribution of karst water resources, scientifically evaluate the amount of groundwater resources, and formulate water resources development, utilization and protection plans according to local conditions, to provide technical support for poverty alleviation, ecological civilization construction and rural revitalization.
      Highlights: Based on the systematic hydrogeological and environmental geological comprehensive survey and the demonstration work of groundwater development and utilization, systematically summarizes the attributes of groundwater resources in the southern karst zone; In view of the issue of water resource security in karst zones, the major reasons for this are analyzed are proposed, and water resources protection countermeasures are proposed.

    • FENG Jing, ZHU Zhixin, ZHAO Tongyang, CHEN Zhengle, GU Xuexiang, MENG Guixiang, XU Shiqi, TIAN Jiangtao, LI Ping

      2022,49(4):1154-1178, DOI: 10.12029/gc20220409

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective]Stretched across the Paleo-Asian Ocean and the Paleo-Tethys Ocean, the long-term ocean-land transformed process of Xinjiang Region has created a unique history of crustal accretion and diverse mineralization. As an important resource base for energy, nonferrous metals, iron ore, potash, and non-metals in China, there are 152 kinds of minerals had been discovered and over 3000 mines had been built in Xinjiang. Furthermore, abundant exploration and development bases, dominated by dominant minerals including oil, natural gas, coal, iron, manganese, lead, zinc, copper, nickel, gold, antimony, uranium, rare metals, fluorite, potassium salt, etc, have been formed by the end of 2019. For further analyzing the coupling relationship between multi-stage and multi-cycle crustal growth process and mineralization in Xinjiang, the research on division of tectonic units in Xinjiang is expected for more accurate metallogenic prediction and evaluation, and is urgent for better serving the national energy and resource security strategy.
      [Methods]Based on the comprehensive analysis of sedimentary formation, volcanic formation, intrusive formation, metamorphic formation, structural deformation, and metallogenic regularity in Xinjiang, a new division scheme of tectonic units in Xinjiang is put forward under the guidance of "Ocean Plate Geology" and the analysis of accretionary orogenic process, combined with the metallogenic response under different tectonic backgrounds.
      [Results]The new structural unit division scheme includes 6 primary structural units, 14 secondary structural units, 32 tertiary structural units, and 99 quaternary structural units. It is proposed that the Tarim craton is bounded by the Paleo-Asian Ocean tectonic domain in the north and the Tethys Ocean tectonic domain in the south. According to the relationship between crustal evolution and mineralization in Xinjiang, the metallogenic theory of "three systems, two belts, one block, and one edge" is creatively proposed.
      [Conclusions]Four tectonic metallogenic stages in Xinjiang are systematically proposed, including the formation of the Archean to Paleoproterozoic ancient continental core with iron-copper metallogenic stage, the formation of the middle-Proterozoic to middle-Neoproterozoic Tarim ancient basement and the Paleozoic ocean continental block with iron-lead-zinc-apatite-asbestos-gem-quartzite metallogenic stage, the accretion and aggregation of continental crust in Nanhua to Triassic with oil-gas-gold-copper-nickel-lead-zinc-iron-manganese-antimony-tungsten-molybdenum-rare metals-asbestos-raphite-mica-andalusite-gem metallogenic stage, and the formation and evolution of basin mountain structures from Jurassic to present with oil-gas-coal-uranium-lead-zinc-salt metallogenic stage.
      Highlights: (1) Guided by "the theory of Ocean plate geology" and combined with the metallogenic specificity of different tectonic environments, a new tectonic pattern of "three systems, two belts, and one block" in Xinjiang is put forward. (2) The deposit types in Xinjiang are mainly magmatic hydrothermal type, biochemical sedimentary type, chemical sedimentary type, marine volcanic rock type, magmatic type, and metamorphic type. (3) There are four tectonic metallogenic stages are divided, and a new metallogenic theory of "three systems, two belts, one block, and one edge" is creatively proposed in Xinjiang. The Mesozoic mineralization is considered as the main metallogenic period of geological exploration and prospecting in Xinjiang in the future.

    • FU Chao, DANG Zhicai, LI Junjian, Zhou Shumin, NI Zhenping, PENG Yi, SONG Lijun, ZHANG Tong, HOU Zhanguo

      2022,49(4):1179-1197, DOI: 10.12029/gc20220410

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective] Gold deposit is one of the dominant minerals in North China, which is rich in resources and diverse in types. It is of great significance to carry out the research on the characteristics of gold resources and metallogenic regularity for further deployment of gold exploration in North China.
      [Methods] Based on the systematic collection of the previous gold research results in this area, the resource endowment, types of deposits, characteristics of spatiotemporal distribution and ore controlling, metallogenic evolution and potentiality have been summarized comprehensively.
      [Results] Firstly, according to the genetic type of the deposit,six types of deposits can be divided in North China, including the types of granite greenstone, volcanic, magmatic hydrothermal, metaclastic hydrothermal, placer and weathering crust. Secondly, it can be divided into 44 types of mineral prediction, among which the types of magmatic rocks, volcanic rocks and greenstones are the most important.Besides, statistics precise chronology data of gold deposits indicate that there are 5 periods of gold mineralization in the geological history in North China. These periods are Wutai-Lüliang, Variscan, Indosinian, Yanshanian and Himalayan. The Au mineralization during Yanshanian period is the strongest one.The gold deposits are mainly occurred in the margin of North China Craton, rift zones and orogenic belts, which formed in continental rift, island arc (volcanic arc) and active continental margin environments.
      [Conclusions] The comprehensive analysis shows that 47 important gold prospecting prospects can be divided in North China, and deep exploration and peripheral investigation in important prospective areas and ore concentration areas should be strengthened to achieve a breakthrough in gold prospecting.
      Highlights: This paper comprehensively summarizes the resource endowment, types of deposits, characteristics of spatiotemporal distribution and metallogenic potentiality, and divides 47 important prospecting prospects in North China.

    • Research Articles
    • YANG Zhengkun, YANG Yang, ZHANG Zhongkun, LIN Bin, HE Jian, ZHANG Zebin, GAO Futai, TANG Xiaoqian, TANG Pan, QI Jing, LI Yixuan

      2022,49(4):1198-1213, DOI: 10.12029/gc20220411

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective]As one of the most important porphyry metallogenic systems in Gangdese metallogenic belt in Tibet, Jiama has a four in one orebody structure of porphyry, skarn, hornfels, and vein gold ore-body, forming riched minerals and diverse metal mineralization. Pyrrhotite is one of the important metal minerals, and its mineral geochemistry and relationship with gold mineralization are still obscure.
      [Methods]The mineralogy and geochemistry of pyrrhotite in different occurrences of the Jiama porphyry system are the main objects for this paper according to detailed field geological survey, petrography, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis.
      [Results]The results show that pyrrhotite is obviously enriched in Co, Ni, Cu, Zn, Ge, and Se, and weakly enriched in Pb, Bi, Sb, Te, Ag, and As, and low content of Mo, Cd, In, Sn, Ba, W, Au, Tl, Th, U, relatively. Moreover, the pyrrhotite from skarn has a high ratio of Co/Ni, represent the its magmatic-hydrothermal genesis, while the pyrrhotite hosted in hornfels shows sedimentary characteristics.
      [Conclusions]The variation of contents of Cu, Zn, and Pb in pyrrhotite are related to the spatial mineralization in the Jiama deposit. The massive pyrrhotite in skarn is closely related to gold mineralization and the gold is mainly anhedral or irregular free gold occurring in the cavity and boundary of pyrrhotite grains. The enrichment and precipitation of gold could be related to bismuth-rich melts in the ore-fluids.
      Highlights: Pyrrhotite is one of the important metal mineral in the Jiama deposit. The LA-ICP-MS analysis of pyrrhotite shows its geochemistry and genesis. The high-grade Au in pyrrhotite hosted in skarn could be related to the bismuth-rich melts in the orerelated fluids.

    • LIANG Bin, FU Xiaofang, LI Shihong, TANG Yi, PAN Meng, HAO Xuefeng

      2022,49(4):1214-1223, DOI: 10.12029/gc20220412

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective] The Jiajika rare metal mining area is the largest granite pegmatite-type rare metal deposit in China. The recently discovered Vein X03 is an supergiant rare metal deposit dominated by lithium. The tourmaline and cordierite contact metamorphic zones have been developed in the surrounding rocks of Vein X03, and mineralization of rare metals such as Li, Rb, and Cs occurs in the altered rocks. Cs is one of the important rare metal elements, and it is imperative to find more available cesium resources.
      [Methods] In this research, the content of rare elements in the contact metamorphic rock samples in drilled cores, such as tourmaline cornerstone and cordierite schist, was analyzed. The monomineral microanalysis of tourmaline, cordierite, biotite and white mica was conducted using LA-ICP-MS.
      [Results] High contents of Li, Rb, and Cs in the contact metamorphic rocks were observed, and the average values were 0.296%, 0.067%, and 0.052%, respectively. The contents of these elements reach the boundary grade or the lowest industrial grade for comprehensive utilization, and its characteristics are very similar to those of altered rock cesium mica deposits. Cs element mainly occurs in biotite in the form of isomorphism, which is the main reason for the enrichment of Cs in the contact metamorphic rocks.
      [Conclusions] In the further exploration of Vein X03, the rare metal resources, especially Cs resources, in the contact metamorphic rocks should be evaluated and comprehensively utilized.
      Highlights: The contents of rare elements, such as Cs, in the contact metamorphic rocks of Vein X03 was analyzed. Cs element mainly occurs in biotite in the form of isomorphism, which should be comprehensively utilized.

    • LI Shanpo, QIAO Xinxin, CHEN Junkui, ZHENG Kai, PAN Xiaona, WU Xiangke, ZHANG Shaobo, ZHANG Rongzhen, GAO Chuanbao

      2022,49(4):1224-1235, DOI: 10.12029/gc20220413

      Abstract:

      This paper is the result of mineral exploration engineering.
      [Objective] Dazhuang deposit is a newly discovered medium-sized Nb-REE deposit (Nb2O3=16245t; Associated TRE2O3=30147 t) in Fangcheng, Henan Province and its ore body occurs within alkaline syenite.
      [Methods] In this paper, the authors compared the differences between ore-bearing and barren alkaline syenites in terms of petrology, petrography and geochemistry based on detailed field observation.
      [Results] The results show that both ore-bearing and barren alkaline syenites belong to typical A-type granite which is rich in alkaline and aluminium and there is no significant differences in alkali metal contents between them, whereas the ratios of (Na2O+K2O)/CaO, FeO*/MgO, K2O/MgO are obviously different. Moreover, the ore-bearing alkaline syenite has high contents of high field strength elements such as Nb, Ta, Ce, U, Th, Zr and Y, but is depleted in Ba, Sr, P and Eu. The barren alkaline syenite displays high content of large ion lithophile elements of Rb and some high field strength elements such as Nb, Ta, Y and is depleted in Ba, U, Sr, P, Ti and heavy rare earth elements however, its depleted degree is lower than that of ore-bearing alkaline syenite.
      [Conclusions] The comprehensive analysis implies that the ore-bearing alkaline syenite in Dazhuang deposit was not the product generated by hydrothermal alteration (albitization) of barren alkaline syenite, but formed from the same magmatic system at different evolution stages. The fractionation degree of the ore-bearing alkaline syenite is obviously higher than that of barren syenite and the enrichment of rare elements and rare earth elements in Fangcheng Dazhuang deposit is closely related to the high evolution process of A-type magma. These results may provide some petrological evidences for the REE prospecting in Fangcheng district.
      Highlights: Conclude that the ore enrichment mechanism is closely related to the high fractionation process of magmatic system. These results provide some petrological evidences for ore prospecting in Fangcheng district.

    • JIN Zhongguo, LIU Kaikun, ZHENG Minghong, LUO Kai, YANG Shengfa, CHUN Guo, WANG Qiong, FAN Yunfei

      2022,49(4):1236-1249, DOI: 10.12029/gc20220414

      Abstract:

      This paper is the result of mineral exploration engineering. The Sansui deposit is located in the uranium metallogenic belt between central Guizhou and northwest Hunan Province. It is the first large uranium deposit discovered in Guizhou Province in recent years. The uranium deposit situates in the carbonaceous mudstone of Laobao Formation of Sinian-Cambrian and is stratified and like stratified.
      [Objective] The purpose of this paper is to find out the ore and mineral composition of Sansui uranium deposit, explore the uranium mineralization environment, reveal the mineralization process of uranium initial enrichment, leaching, superposition and re-enrichment, and provide new information for regional metallogenic prediction, ore exploration and enrichment of this type of uranium ore-forming theory.
      [Methods] The study on mineral mineralogy and geological characteristics of ore deposits shows that
      [Results](1) The Laobao Formation of uranium-bearing rocks was formed in the anoxic reduction environment of the continental margin rift and continental margin rifting during the Sinian/Cambrian transitional period. (2) The uranium ore is mainly composed of uranium mineral, iron ore, clay mineral, organic matter, dolomite, quartz (or chalcedite), barite, calcite, etc., with microcrystal-cryptocrystal structure, microcrystal-powder grain structure, layered and lamellar structure. (3) The uranium ore is rich in uranium minerals, mainly pitchblende, silica-calcined uranium ore, selenium-lead uranium ore, titanium-uranium ore, phosphorus uranium ore and water-carbon uranium, etc. They occur in the form of nano-micron granule, column (particle size <10 microns), veinlet, or in the form of cryptocrystalline occurrence in the organic matter, iron, clay minerals and other uranium minerals. (4) The constant element in the ore were enriched in SiO2, CaO and LOI (burning loss), which was consistent with the rich silica, calcium and organic minerals.
      [Conclusions]The uranium source of the Sansui deposit was related to the submarine volcanic eruption, spillage during the Xuefeng period and the weathering and leaching of uranium-bearing geological bodies. Mineralization and its associated trace elements such as U, V, Mo, Cd, Se, Ni, Zn, etc. are significantly enriched, which is related to the fact that some ore-forming materials and ore-forming fluids are continuously leaching ore-forming materials in the strata during the process of submarine volcanic eruption and spill.
      Highlights: Ore-forming materials and ore-forming fluids of the Sansui deposit are continuously leaching ore-forming materials in the strata during the process of submarine volcanic eruption and spill.

    • LIU Wei, HUANG Lishan, DING Rufu, XU Wenjie, HU Qiaofan, ZHOU Shouyu, ZHAO Yi

      2022,49(4):1250-1261, DOI: 10.12029/gc20220415

      Abstract:

      This paper is the result of mineral exploration engineering
      [Objective]Through the comprehensive information prospecting model of Jianzhupo antimony polymetallic deposit, it is of great significance to further develop the location prediction of deep ore body.
      [Methods]Based on the prospecting work of antimony polymetallic ore in Jianzhupo deposit, this paper studies the deep metallogenic model and analyzes the role and effect of controlled source audio frequency magnetotelluric sounding (CSAMT), transient electromagnetic survey (TEM), geoelectrochemical survey and other methods in deep prospecting.
      [Results]Controlled source measurement can reflect the depth of the deep fault zone, transient electromagnetic measurement with low resistivity can effectively identify the mineralized zone or ore-controlled fault zone, and geoelectrochemical measurement of Pb, Zn, Sb elements change curve peak can indicate the existence of mineralized bodies.
      [Conclusions]Hedgehog slope antimony polymetallic geological and geophysical-geochemical measurement with the establishment of a comprehensive information prospecting model for five fair in deep prospecting provides the detection of target can be recognized, CSAMT, TEM and electrochemical measurement synthesis method can detect deep characteristics of orecontrolling fracture, characteristics of comprehensive information prospecting method is an effective technical means of construction controlling.
      Highlights: A multi-source information prospecting model is established by using the comprehensive prospecting method of geology-geophysical and geochemical exploration to predict the location and size of deep ore bodies.

    • SHAO Wei, HUANG Zhengqing, LI Jianqing, ZHOU Daorong

      2022,49(4):1262-1274, DOI: 10.12029/gc20220416

      Abstract:

      This paper is the result of oil and gas exploration engineering.
      [Objective] The dark shale of the Cambrian Hetang Formation widely occurred in southwestern Zhejiang and northeastern Jiangxi is the key target of shale gas exploration in the Lower Yangtze region. However, due to the present low exploration level of this interval, understanding of the shale gas accumulation conditions is still insufficient.
      [Methods] Based on the analysis of geological background, organic geochemical indicators and field stratigraphic outcrop investigation of the dark shale, the shale gas resource potential is evaluated and the favorable areas are optimized.
      [Results]The dark shale ranges from 35 to 200 meters in thickness with an average of over 50 meters in Jiangshan-Changshan area and is characterized by medium to high content of organic matter (TOC ranging from 1.48% to 23.53%) and high to over maturity (Ro ranging from 2.01% to 3.0%). The organic matters are highly and over highly matured. Abundant micropores and microfractures were observed in the shales, indicating the high quality shale reservoirs. The isothermal adsorption experiment shows that the carbonaceous shale has strong adsorption ability, which reaches 5.93 kg/t on average.
      [Conclusions]It is suggested that the region of Jiangshan-Changshan area in western Zhejiang is favorable for shale gas exploration on the basis of relatively low thermal evolution of organic matter and stable stratigraphic structure preservation conditions.
      Highlights: The shale of Cambrian Hetang Formation in southwest Zhejiang-northeast Jiangxi has the material basis of shale gas enrichment;Thermal evolution is the key to the enrichment of shale gas in the Cambrian Hetang Formation in the Lower Yangtze area.

    • FAN Saihua, XIE Hui, LI Binwen, LIU Yuan, LI Weiping, XU Weina, ZHAO Hu, MOU Lei

      2022,49(4):1275-1284, DOI: 10.12029/gc20220417

      Abstract:

      This paper is the result of oil and gas exploration engineering.
      [Objective] The exploration potential of conventional structural advantage area of gas reservoir in Jurassic Shaximiao Formation in the eastern slope of western Sichuan depression is not great, and the geological understanding of the gas reservoir in the complex fault clamping area with low degree of exploration is obviously lagging behind.
      [Methods] Based on the data in exploration and developent in recent years, using the theory of structural reservoir control, this paper studies the control of fault section morphology type and fluid potential difference on oil and gas accumulation, discusses the oil and gas distribution in the fault clamping area, and summarizes the difference of oil and gas enrichment in the north-south fault system.
      [Results] The study shows that the river channel controlled by slope-flat fault has a high degree of oil and gas filling, which is conducive to high-efficiency reservoir formation, followed by low-angle shovel-like fault, and high-angle flat shovel-like fault has the worst reservoir formation.
      [Conclusions] Fluid potential difference makes it difficult for hydrocarbon source cliff gas to fill long-distance sand bodies through high potential areas. Although it is difficult to form reservoirs due to the escape of oil and gas in the development of a narrow fracture network at both ends of the fracture clamping area, a relatively good oil and gas enrichment zone can be formed in the wider middle if the slope-flat fault and low-angle shovel-like fault are clamped and transported together.Therefore, it is believed that the structure in the south is superior to that in the northern and central clamping areas and has certain potential. The key factors of reservoir formation are still controlled by the fracture morphology and transportation capability.

    • SUN Qiushi, ZONG Wenming, WANG Sijia, SUN Shouliang, LI Yongfei, GAO Xiaoyong, ZHANG Tao

      2022,49(4):1285-1294, DOI: 10.12029/gc20220418

      Abstract:

      This paper is the result of oil and gas exploration engineering.
      [Objective]The target layer for oil and gas exploration in the Niuyingzi depression in western Liaoning Province has been MesoNeoproterozoic. Due to tectonic uplift and other factors, the Jurassic Beipiao Formation, which is an important hydrocarbon exploration target widely exposed in other basins in western Liaoning, is not found on the surface of this depression.
      [Methods]During the drilling of the LLD1 well, a set of thick dark mudstone layers were discovered beneath the Mesoproterozoic carbonates. Based on correlations of lithology and spore-pollen assemblages of the newly discovered mudstones with those from the Beipiao Formation in the Sanbaosikeng section of Beipiao Basin in western Liaoning Province.
      [Results]The layers discovered were from the Beipiao Formation.
      [Conclusions]Organic geochemical indexes indicate that the mudstone is of high organic matter abundance and high hydrocarbon generation potential. Hence, mudstones from Beipiao Formation in this area is a set of high-quality hydrocarbon source rock worthy of exploration. The discovery of thick dark organic-rich layers indicates that the Jurassic Beipiao Formation is a new target for oil and gas explorations in the Niuyingzi Depression. Moreover, this new discovery also provides important basic geological information for the study of tectonic evolution and hydrocarbon geological conditions in western Liaoning Province.
      Highlights: The dark mudstone below the middle Proterozoic nappe in LLD1 well is identified as Beipiao Formation by means of sporo-pollen assemblage and lithologic assemblage; According to geochemical indexes, the strata are identified as high quality hydrocarbon source rocks.

    • YAN Songtao, WU Qingsong, TAN Changhai, LIU Longqiang, ZHANG Yong, LI Yusheng

      2022,49(4):1295-1308, DOI: 10.12029/gc20220419

      Abstract:

      This paper is the result of geological survey engineering.
      [Objective]By finding out the age and geochemical characteristics of granodiorites in Lazhagashan area, this paper discusses the age, genesis and tectonic background of granodiorites, so as to provide a basis for the study of subduction-accretion processes in the Ganzi-Litang Ocean Basin.
      [Methods]Our project carried out systematically study the petrography, LA-MC-ICP-MS zircon UPb chronology and rock geochemistry from the granodiorites in subduction accretion complex of Ganzi-Litang ophiolite melange belt.
      [Results]The granodiorites contain a large amount of femic mineral such as amphibole, biotite, and a large number of dioritic enclaves and surrounding rock xenoliths. The intrusive rocks were formed in the Late Triassic ((207.2±1.5)Ma), and are I-type calcalkaline quasi-aluminous granites with enriched in large-ion-lithophile elements (LILE), such as Rb, Ba, K, Th and U, depleted in high-field-strength elements (HFSE), such as Nb, Ta, P, Zr and Ti. It shows a right-leaning pattern of enrichment of light rare earth and depletion of heavy rare earth. It is a typical volcanic arc granite showing strong enrichment of LREE and depletion of HREE, with negative Eu anomaly.
      [Conclusions] Combined with the regional geological data and the research results of this paper, it is considered that the Lazhagashan granodiorite in Litang area is closely related to the westward subduction of the Ganzi-Litang Ocean resulted in the expansion of the accretionary complex in the eastern margin of the Zhongza block, which is the product of melting accretionary complex into different types of magma mixing.
      Highlights: The Lazhagashan granite in Litang area was formed in Late Triassic with typical geochemical characteristics of volcanic arc granite. It was formed in the melting of accretionary complex due to westward subduction of the Ganzi-Litang Ocean, which provides new evidence for the subduction and accretionary tectonic evolution of the Ganzi-Litang Ocean.

    • WEI Chunxia, LU Gang, YANG Feng, LI Wei, ZHONG Fengyun, JIN Jingjie, PAN Yiwen, LIANG Lijie, BAI Xiao

      2022,49(4):1309-1322, DOI: 10.12029/gc20220420

      Abstract:

      This paper is the result of geological survey engineering.
      [Objective]Eastern Liuzhou is located in the eastern margin of Youjiang Basin. In recent years, a set of volcanic rock interlayer has been found in the Early Triassic Shipao Formation in the eastern Liuzhou for the first time, which provides an important basis for studying the tectonic evolution of the eastern margin of the Youjiang Basin.
      [Methods]Taking the newly discovered volcanic rocks in Eastern Liuzhou as the research object, this paper investigates the formation age and magmatic source characteristics of the volcanic rocks in the eastern margin of the Youjiang Basin through LA-ICP-MS zircon U-Pb age and Hf isotope analysis.
      [Results]The results show that the volcanic rocks are composed of tuff, tuff lava, and tuffaceous volcanic breccia, showing typical characteristics of volcanic rock. LA-ICP-MS zircon U-Pb age dating results show that the weighted mean ages of zircon in the two tuff samples are (244.0±1.9) Ma and (247.1±0.9) Ma respectively. The trace elements (U, Th, Hf, Nb) compositions of zircon show the characteristics of continental magma arcs-derived zircons. The zircon have εHf(t) values of-13.2--1.2, with second-stage model ages (TDMC) of 1.35-2.06 Ga, suggesting that their magma source is mainly crustal materials, with average crustal residual age of 1.7-2.06 Ga.
      [Conclusions]The timing volcanic rock interlayer is basically consistent with the stratigraphic age of the Early Triassic Shipao Formation, and are the product of volcanic eruption during the late Early Triassic to the early Middle Triassic. The volcanic rocks were formed in volcanic arc-related, syn-collisional tectonic setting, which is the representative of the sedimentary environment of back-arc basin, and is related to the closure of the paleo-Tethys during the Indosinian period. This outcome provides new and crucial information for a better understanding the tectonic evolution of the paleo-Tethys.
      Highlights: The volcanic rocks in eastern Liuzhou are the products of volcanic eruption during the late Early Triassic to the early Middle Triassic, and were formed in volcanic arc-related, syn-collisional setting related to the closure of the Paleo-Tethys.

    • SHANG Yongming, LI Xiaowei, ZHU Xinyou, ZOU Tao, HUANG Xingkai, CHENG Xiyin, WANG Li, WANG Shuxing

      2022,49(4):1323-1345, DOI: 10.12029/gc20220421

      Abstract:

      This paper is the result of geological survey engineering.
      [Objective]The Wushijiazi pluton in Chifeng area, Inner Mongolia, is located in the southwestern part of the metallogenic belt of the southern Great Xing'an Range. A systematic geochronological and geochemical study can provide insights into understanding of regional tectonic-magmatic evolution and metallogenic regularity.
      [Methods]Based on the petrological and geochemistry study, this paper uses LA-ICP-MS zircon U-Pb dating, major and trace element analysis and Zircon Hf isotopic analysis methods to analyze the genesis of the pluton.
      [Results]LA-ICP-MS zircon U-Pb dating results show that the porphyritic biotite-bearing monzogranite, porphyritic biotite-bearing syenogranite and porphyritic biotite syenogranite in the Wushijiazi pluton were formed at (150.3±1.3) Ma, (145.9±1.8) Ma and (137.1±2.2) Ma, respectively, which are the magmatic products during the Late Jurassic to Early Cretaceous. The pluton is geochemically characterized by high contents of silica and alkalis, but low contents of aluminium and calcium, belonging to alkaline and quasi aluminous-weakly peraluminous A-type granites. Zircon Hf isotopic analysis displays that the porphyritic biotite-bearing syenogranite has positive εHf(t) values (+7.5-+14.3) and juvenile two-stage (tDM2) Hf model ages (tDM2=285-718 Ma), which was consistent with those of Late Mesozoic granites in the southern of Great Xingan Range. Therefore, it is suggested that the contribution of the juvenile lower crust is dominant in the source region. The occurrence of mafic microgranular enclaves in porphyritic biotite-bearing monzogranite indicates magma critical role of mantle-crust interaction.
      [Conclusions]Combined with regional geological background, our study suggests that the asthenosphere upwelling resulted in partial melting of the juvenile lower crust and formed the primitive magma mush under the late Mesozoic lithospheric extension and thinning environment, and then the magma mush mixed with the mantle-derived magma. The highly fractionated mixed magma was emplaced in the shallow level, and finally formed the Wushijiazi granitic pluton. Wushijiazi pluton is characterized by the high degree of differentiation, as well as deep-source but shallow-emplacement, which is closely related to the tin-polymetallic mineralization in this area.
      Highlights: The formation time of the three lithofacies of the Wujiazi pluton was obtained by LA-ICP-MS zircon U-Pb dating method, and the genesis of the pluton was comprehensively deciphered according to the petrographic characteristics, diagenetic time, geochemical characteristics, zircon Hf isotope characteristics and regional geological background.

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    Volume 49,2022 Issue 4
    • 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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