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Overview of the Application and Prospect of Common Chemical Weathering Indices LI Xulong, ZHANG Xia, LIN Chunming, HUANG Shuya, LI Xin Geological Journal of China Universities    2022, 28 (1): 51-63.   DOI: 10.16108/j.issn1006-7493.2020118 Abstract （8343）      PDF（pc） （1109KB）（11785）       Knowledge map    Save Common chemical weathering indices such as the Weathering Index of Parker (WIP), the Chemical Index of Alteration (CIA), the Index of Compositional Variability (ICV), CIX index and αAlE are often used to evaluate the chemical weathering intensity of source areas. But the factors which controlling the above chemical weathering indices should be considered, otherwise the results of the weathering evaluation will be distorted. This paper argues that the geological survey of source area should be known when chemical weathering indices are used to study the chemical weathering process. The selection of fine sediments or suspended matter can weaken the influence of grain size on chemical weathering indices. The impurities in the sediments are removed by acid treatment. Then, the Sc/Th-CIA diagram was used to reflect the material source information, Th/SC-Zr/Sc diagram was used to further distinguish the control effect of sedimentary differentiation and sedimentary recirculation, and then the samples with ICV value less than 1 were selected to eliminate the interference of recirculation. The A-CN-K diagram or the formula proposed by Panahi (2000) were used to correct the potassium metasomatism, and the strength of chemical weathering of source rocks was evaluated by CIA eventually. To ensure that the calculation of chemical weathering indices can accurately reflect the weathering situation of the source area, SPSS software can be used to analyze the proportion of some factors which affecting the CIA to construct characteristic weathering index of the study area. Related Articles | Metrics | Comments（0）

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An Overview of Characteristics and Prospecting of Gold Ore Deposits in China WANG Bin，LI Jingchao，WANG Chengxi，ZHENG Xiao，SUN Kefeng Acta Metallurgica Sinica    2020, 26 (2): 121-.   DOI: 10.16108/j.issn1006-7493.2019033 Abstract （2639）      PDF（pc） （2571KB）（7958）       Knowledge map    Save Based on the geodynamic settings of gold metallogenesis and the basic geological features of gold ore deposits, China’s gold deposits can be classified into 11 categories. Among these categories, the structurally-fractured altered-rock type, inner and outer contacting belts type of plutonic intrusives, the Carlin or quasi-Carlin type, hydrothermal type within low-grade metamorphic clastic rocks, and continental volcanic rock types are the types of interest in prospecting. As far as metallogenic ages concerned, those that occurred in Mesozoic and Cenozoic are the major types. According to their geotectonic units, geological evolution, metallogenic geological conditions, spatial-temporal distribution, gold deposit types, regional metallogenic factors, and volumes of mineral resources, totally 42 gold ore concentration areas, which are spatially distributed in clusters, have been preliminarily identified on the basis of China’s III-graded classification scheme of metallogenic zones (belts). According to gold prospecting borehole quantities per unit area, China’s gold ore concentration areas can be categorized into 3 levels, i.e., highly, moderately, and lowly developed. The highly developed ones are mainly distributed in Central and Eastern China. Except the placer gold deposits, about 88.12% boreholes for primary gold (rock gold or associated gold) deposits are less than 500 m with deep in China, suggesting that the quantities and depths of gold exploration drillings in China are less and shallower than in other countries. As for the gold resources exploration potentials, we propose that (1) in Central and Eastern China, the deep parts and the peripheries of the existing gold mines are key locations to be focused on; (2) for Western China, the gold ore concentration areas, which are located especially in Xinjiang Uygur Autonomous Region, Qinghai Province, and Tibet Autonomous Region, are the future key regions with immense potentials for unexplored gold resources. Related Articles | Metrics | Comments（0）

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Quantitative Analysis of Differential Rifting Process in the Xijiang and Lufeng Sags of the Zhu 1 Depression, Pearl River Mouth Basin, Northern South China Sea MA Bingshan, QI Jiafu, WANG Junhuai, NENG Yuan, YU Fusheng, CHEN Weichang, WU Guanghui, GE Jiawang Geological Journal of China Universities    2022, 28 (5): 669-687.   DOI: 10.16108/j.issn1006-7493.2022033 Abstract （1150）      PDF（pc） （7646KB）（7072）       Knowledge map    Save The Xijiang and Lufeng Sags are located in the Zhu 1 Depression of the Pearl River Mouth Basin in the northern South China Sea; the former displays a nearly symmetric graben controlled by NE-striking listric boundary faults, while the latter has the “two sag sandwiching one high” tectonic framework controlled by six curved major faults. The structure and rifting evolution show obvious spatial and temporal differences. In this paper, based on the three-dimensional seismic data, basin structure and geometry of fault system were descripted, a total of 8 seismic-geological sections in the two sags were selected for balanced section restoration, and quantitative parameters (e.g. horizontal displacement and depth-to-detachment) during the two rifting stages were calculated. The evolution process and their differences of the two rifts were further analyzed and the relationship with regional tectonic evolution was discussed. In the Cenozoic, the study area experienced the first (period of the Wenchang Formation) and second (period of the Enping Formation) phases of rifting and the subsequent Late Oligocene-Quaternary post-rifting stage. Each rifting phase can be subdivided into early and late sub-phases. The rifting evolution of the Xijiang and Lufeng Sags has temporal and spatial differences. From the first to second phase of rifting, the horizontal displacement of the study area has the general characteristics of decreasing with time. The horizontal displacement of the Xijiang Sag continues to decrease with time, and it still contains large displacement in the late sub-phase of the second phase, while it is slightly increased in the early sub-stage of the second phase in the Lufeng Sag. The degree of extension in the late sub-phase is much weaker in the Lufeng Sag than that in the Xijiang Sag. The depth-to-detachment of the two sags has the characteristics of deepening with time. In the early and late sub-phases of the first phase, the depth-to-detachment of the Lufeng Sag is slightly deeper than that of the Xijiang Sag. In the early and late subphases of the second phase, the average depth-to-detachment of the Xijiang Sag increases from ~8 km to ~9 km, while the average detachment depth of the Lufeng Sag jumps from ~8 km to ~35 km. The geometric structure, fault system, horizontal displacement and depth-to-detachment of the study area indicate that the Lufeng Sag was subjected to thermal subsidence in the late sub-phase of the second rifting phase and probably ended the rifting stage earlier, while the rifting of the Xijiang Sag ended after the second rifting phase. The rifting of the study area gradually ending from east to west may be controlled by the seafloor spreading of the Northeast Sub-basin of the South China Sea and the gradual westward seafloor spreading of the South China Sea. The regional plate tectonic evolution also provides the Pearl River Mouth Basin with a differential extension environment with enhanced extension in the SW direction. The differential rifting evolution of the study area is of great significance for understanding the temporal and spatial distribution of the rift time and differential rift evolution in the Pearl River Mouth Basin, and also provides important quantitative constraint for understanding the rifting process in the northern continental margin of the South China Sea.  Related Articles | Metrics | Comments（0）

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Enzyme-induced Calcium Carbonate Precipitation (EICP) and Its Application in Geotechnical Engineering CAO Guanghui, LIU Shiyu, YU Jin, CAI Yanyan, HU Zhou, MAO Kunhai Geological Journal of China Universities    2021, 27 (6): 754-768.   DOI: 10.16108/j.issn1006-7493.2020200 Abstract （4800）      PDF（pc） （4975KB）（6671）       Knowledge map    Save The technique of improving soil by enzyme-induced calcium carbonate precipitation is called EICP, which has attracted more and more attention over the past decade due to its wide application. The article describes the mechanism of EICP and summarizes the extraction methods of plant urease and bacterial urease. In addition, the influence of factors such as urease, calcium source, urea, skimmed milk powder, temperature and pH on the cementing effects of EICP is explored. Furthermore, methods for testing the strength, calcium carbonate content, microstructure and composition of EICP reinforced samples are summarized, and the application of EICP in geotechnical engineering is evaluated. The purpose of this article is to summarize the current status of EICP research and potential problems that need to be overcome in future research. Related Articles | Metrics | Comments（0）

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Development Features of Triassic Strata and Analysis of Original Sedimentary Pattern in North China PENG Zhao-meng, WU Zhi-ping J4    Abstract （817）      PDF（pc） （259KB）（5406）       Knowledge map    Save Based on the study on characteristics of vertical development and lateral distribution of Triassic in North China, and with the analysis of lithological characteristics, changes of strata thickness, strata contact relationships, as well as the research about the denuded thickness of strata, the influence of the Indosinian movement exerted on the sedimentation of North China during Triassic was analysed, and the original sedimentary pattern in North China during this period was studied and discussed. The research shows that there was a large-scale sedimentary basin inside the North China Plate during Early and Middle Triassic. It inherited the structural pattern and sedimentary characteristics of the Late Hercynian, and mottled sediments of fluvial-lacustrine facies developed. Beginning from the Late Triassic and caused by the Indosinian orogeny, the strata in the east of North China were uplifted and the Lower and Middle Triassic were denuded. In some areas, the Paleozoic was also denuded, and the intermountain basins were developed only in restricted areas. There still was a basin with sediments of fluvial-lacustrine facies under warm and humid climate in the southeast of North China, but its scale became smaller Related Articles | Metrics | Comments（0） Cited: Baidu(28)

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Status and Advances of Research on Caprock Sealing Properties of CO2 Geological Storage CHEN Bowen, WANG Rui, LI Qi, ZHOU Yinbang, TAN Yongsheng, DAI Quanqi, ZHANG Yao Geological Journal of China Universities    2023, 29 (1): 85-99.   DOI: 10.16108/j.issn1006-7493.2023010 Abstract （3168）      PDF（pc） （6425KB）（5328）       Knowledge map    Save CO2 Geological storage is one of the key technologies to address global climate changes and reduce greenhouse gas emissions. Large-scale CO2 injection into the formation is prone to inducing CO2 leakage problem. In particular, the leakage problem of CO2 through caprock includes capillary leakage, hydraulic fracture and leakage along pre-existing faults crossing caprock. Therefore, evaluation of caprock seal is crucial for prediction of long-term safety and stability of CO2 geological storage. This paper provides an overview of the current status of research on sealing mechanisms, influencing factors, and damage modes affecting caprock seal of CO2 geological storage. It is concluded that caprock seal mechanisms include capillary seal, hydraulic seal, and overpressure seal. The main influencing factors of caprock seal characteristics include caprock lithology, mudrock-sand ratio, caprock mechanical properties, and sequestration pressure. Then, the damage modes of caprock seal during CO2 injection are illustrated, and some insight into the shortcoming of caprock seal is provided. Related Articles | Metrics | Comments（0）

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Advances in the Study of Biogeochemical Cycles of Phosphorus ZHOU Qiang, JIANG Yunbin, HAO Jihua, JI Junfeng, LI Wei Geological Journal of China Universities    2021, 27 (2): 183-199.   DOI: 10.16108/j.issn1006-7493.2020002 Abstract （4504）      PDF（pc） （2398KB）（5028）       Knowledge map    Save Phosphorus is an essential element for life and an important limiting factor for food production. The biogeochemical cycles of phosphorus not only regulate marine primary production, but also has an impact on the global climate system; it also determines the formation and distribution of phosphate resources and affects the continuity of life on earth. The current theory of “earth system science” integrates the subsystems of atmosphere, hydrosphere, lithosphere (crust and upper mantle) and biosphere, providing a broader view for studying the global phosphorus cycles. Based on the existing research and combined with the theory of “earth system science”, the following important understandings of the biogeochemical cycles of phosphorus has been obtained: The evolution of phosphorus in geological history determines the current cycle pattern of phosphorus on a global scale (terrestrial ecosystems and marine ecosystems); Human industrial and agricultural activities, as an important geological agent, has changed the biogeochemical cycles of phosphorus, resulted in resource crisis of phosphate depletion and environmental problem of eutrophication of water bodies; The key to solve the resource crisis problem of phosphorus shortage and environmental pollution problem of phosphorus surplus lies in regulating the biogeochemical cycle process that cause these problems.  Related Articles | Metrics | Comments（0）

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Predevonian Tectonic Evolution of South China: from Cathaysian Block to Caledonian Period Folded Orogenic Belt SHU Liang-shu J4    Abstract （1488）      PDF（pc） （501KB）（4577）       Knowledge map    Save The interpretation of Predevonian tectonics of South China is controversial long time both on its age and distribution. Based on the middle-high grade metamorphic rocks, ductile slipping rheologic structures exposed in the the Zhejiang- Fujian-Jiangxi-Guangdong domain and high quality dating data published recently, the author believes that an ancient continental block existed certainly in South China, which is composed of Proterozoic schist, gneiss and migmatite with an oldest age of 2 Ga, their protolites are clastic rocks, volcanic rocks and plutons. This old land is temporarily called as Cathaysian Continental Block which is limited in the domain between Shaoxing-Jiangshan-Pingxiang fault and Zhenghe-Dapu fault, and its scope is less than that defined by Grabau. During 800-900 Ma, following the closure of paleo-South China ocean, Cathaysian block collided with Yangzi block and then became a part of Rodinia supercontinent. Not long time after converging, by affection of breakup of Rodinia supercontinent, proto-Cathaysian continental block was split into three sub-blocks, namely the southeastern Zhejiang-northwestern Fujian, the central-southern Jiangxi and the Yunkaidashan, and several rifts or sea channels occurred among them. From Early Sinian to Late Ordovician, these sea channels were expanded and were filled by 10000-20000 m thick clastic rocks (containing limestone) and turbidites. However coeval ophiolite and volcanic rocks are absent, implying extended fault did not reach to upper mantle. New geochronological results indicate that the ophiolite and volcanic rocks in the study areas, which were described as Early Paleozoic by previous researchers, yielded pre-Sinian ages, concentrating mainly between 800 Ma and 900 Ma. Thus, the previous Early Paleozoic tectonic framework needs to be re-constructed. In Silurian, a strong tectono-thermal event took place in South China, causing closure of Sinian-Early Paleozoic sea channels and folding-uplifting of mega-thick sediments. The South China Caledonian fold and orogenic belt was formed on the Proterozoic metamorphic basement. In the study area, folding deformation and ductile slipping rheology are very common, including thrust and strike-slip deformation, the peak period of deformation is 420-400 Ma. At the same time, a violent granitic magmatism was started, forming numerous strongly peraluminous S-type granites with A/CNK (molar Al2O3/[CaO + Na2O + K2O]) > 1.1, and I-type granitoids is rare. Peak period of granitic magmatism took place in the 430-400 Ma. Then, the whole South China Caledonian folded geological bodies were overlain unconformably by Late Devonian conglomerate and coarse sandstone, indicating termination of folding and orogeny. From Late Devonian, a united paleo-geographic and sedimentary environment occurred really in the study domain and its neighboring areas. Related Articles | Metrics | Comments（0）

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Chloritization Sequences in Mudstone during Diagenesis and Its Geological Significance FU Yu, DING Qingfeng*, WU Changzhi Acta Metallurgica Sinica

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Review and Advancements of Studies on Silicate Weathering and the Global Carbon Cycle WU Weihua, ZHENG Hongbo, YANG Jiedong, LUO Chao J4    2012, 18 (2): 215-.   Abstract （1562）      PDF（pc） （436KB）（4336）       Knowledge map    Save Silicate weathering is a major sink of the atmospheric CO2, which directly affects the global carbon cycle and the climate. Since the pioneering work of Walker et al. (1981), studies on“ silicate weathering, carbon cycle and climate changes” have sprung up in recent years. Many advancements have been obtained from computer models to river water geochemistry andfrom large rivers with a drainage area exceeding to 106 km2 to monolithologic small watershed with tens/hundreds km2 drainagearea,. In the global scale, atmospheric CO2 consumption from silicate weathering is about 0.138-0.169 Gt per year. Compared tothe current atmospheric carbon content of 800 Gt, at first glance, this CO2 consumption rate seems so slow that silicate weatheringwould play only a negligible role in the global carbon cycle. However, atmospheric CO2 removed from silicate weathering istransported by rivers and thereafter precipitated in the ocean as carbonate minerals, and the residence time of carbon in carbonaterocks is in excess of millions of years. Therefore, silicate weathering is an important mechanism that modulates the long-termcarbon cycle. Moreover, researches show that the small watersheds draining basalts/ophiolites in the tropical zones have thehighest silicate weathering and CO2 consumption rates. It is estimated that CO2 consumption from volcanic rocks in the tropicalzones represents about 10% of the global export of carbon by silicate weathering, while the tropical volcanic arcs correspond toonly~1% of the exorheic drainage area worldwide. Related Articles | Metrics | Comments（0）

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A Preliminary Study on the Features and Geologic Implication of the Accompanying Metals in Tungsten Deposits in the Nanling Region HUA Ren-min, ZHANG Wen-lan, LI Guang-lai, HU Dong-quan, WANG Xu-dong J4    Abstract （802）      PDF（pc） （575KB）（4106）       Knowledge map    Save The Nanling Range area in South China is the most important tungsten producing district in the world. It also yields great amount of other nonferrous, rare, and precious metal resources as the accompaniments with tungsten mineralization. This paper describes the different situations and characteristics of several accompanying metals, e.g. Sn, Mo, Bi, Ta-Nb, Cu, Au, Ag,Pb-Zn and REE, in tungsten deposits in the Nanling Range and vicinity areas. Sn, Mo, and Bi are the most common and important elements among these accompaniments, whereas Ta-Nb is only accompanied with W deposits related to highly evolved granitic rocks. Cu and Au are not important accompanying members of tungsten mineralization in this area, while Ag and Pb-Zn are much more common in the Nanling tungsten deposits. The paper also explains the factors which caused the different behaviors of these elements from the view of geochemical features, regional geological backgrounds, evolution of granitic rocks, as well as the superposition of multi-staged mineralizations. The geological implication of these accompanying relations is also discussed.After then a big window occurred in the Nanling area, triggering the asthenospheric substance got into the upper crust so that developed large-scale high fractionation paraluminous granite and related polymetallic W-Sn mineralization. It was a relatively quiet period of 150~135 Ma in South China except for the Middle-Lower Yangtze River Valley area located in the northeastern margin of the South China plate. Because starting to change motion-direction to northeast the subucted plate was teared up along the Middle-Lower Yangtze River Valley which used to be a foreland basin of the Triassic Dabie-Sulu orogenic belt. A group of skarn-porphyry Cu-Mo-Au-Fe ore system and related I-type or aidakitic granites developed along the cross of the Middle-Lower Yangtze River Valley with the NE-trending faults at an age range of 145~135 Ma. From 135 Ma the subducted plate moved along several groups of regional-scale NE-striking fault zones comprising the Tan-Lu fault zone, which trigged the Eurasian continent to extensive extension. At the setting developed a lot of linear NE-trending Cretaceous faulting basins and metamorphic cores accompanied with volcanic rock eruption as well as epithermal Cu-Au-Ag ore system, granite-related polymetallic Sn (W) deposits and hydrothermal uranium deposits at age of 120~80 Ma with a peak of 100~90 Ma. Related Articles | Metrics | Comments（0）

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Progress of Methods for Assessing CO2 Mineralization Storage Potential in Basalt GAO Zhihao, XIA Changyou, LIAO Songlin, YU Xiaojie, LIU Muxin, LI Pengchun, LIANG Xi, DAI Qing, HUANG Xinwo Geological Journal of China Universities    2023, 29 (1): 66-75.   DOI: 10.16108/j.issn1006-7493.2022099 Abstract （3654）      PDF（pc） （1109KB）（4105）       Knowledge map    Save CO2 geological storage is an important technology to reduce CO2 emissions, which can safely store CO2 in geological formations for millions of years. Conventional CO2 storage reservoirs include deep saline aquifers and depleted oil and gas reservoirs. Basalt is a new type of CO2 storage reservoir that has been attracting attention in recent years. CO2 storage in basalt would increase the technical method and potential of CO2 geological storage. Storage potential assessment is one of the fundamental works of CO2 geological storage study. This paper systematically examines the current methods for assessing the storage potential of CO2 in basaltic rocks, and analyzes the principles and application scenarios of various methods. Then, the study takes the basalt of Icelandic Active Rift zone as an example to compare each of the methods. The study suggests that the current CO2 mineralization storage potential assessment methods generally include three categories: ① Unit rock storage potential assessment method, which evaluates carbon sequestration potential based on the reaction volume or area of rocks; ② Mineral replacement storage potential assessment method: based on the volume of minerals that can react with CO2 in basalts. ③Pore filling storage potential assessment method, which evaluates the proportion of secondary minerals that can fill reservoirs’ pore space after CO2 mineralization. The authors note that the first method requires special experimental analysis, making it more challenging, the second method is more appropriat for basalts with high porosity and low reactive mineral content, while the third method is more suitable for basqlts with low porosity and high reactive mineral content. Related Articles | Metrics | Comments（0）

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One-stop Sharing and Service System for Geoscience Knowledge Graph ZHU Yunqiang, DAI Xiaoliang, YANG Jie, WANG Shu, SUN Kai, QIU Qinjun, LI Weirong, QI Yanmin, HU Lei, LYU Hairong, WANG Xinbing, ZHOU Chenghu Geological Journal of China Universities    2023, 29 (3): 325-336.   DOI: 10.16108/j.issn1006-7493.2023029 Abstract （2300）      PDF（pc） （7167KB）（3969）       Knowledge map    Save As the most effective way of knowledge organization and service at present, knowledge graph has become the cornerstone of artificial intelligence and has been widely used in semantic search, machine translation, information recommendation and so on. In the era of big data, there is an urgent need of Geoscience knowledge graphs for integrating, mining and analysis of scattered, multi-source and heterogeneous Geo-data and its unknown knowledge intelligent discovery. To promote the construction and application of Geoscience knowledge graphs, the Deep-time Digital Earth (DDE) International Big Science Program has taken knowledge graph as its one of the core research contents since its launch in 2019. After more than three years of construction, DDE has built a large number of Geoscience knowledge graphs, and it strong needs one-stop sharing and service system of these knowledge graphs. Firstly, this paper introduces the content framework, composition as well as characteristics of the DDE knowledge graphs. On this basis, the design of the one-stop sharing and service system for the Geoscience knowledge graph is designed that include the design of the system functional and technical architecture. Finally, the development and operation environment & tools, and key technologies of the system are discussed in detail. The practice has proved that the system can effectively realize the one-stop sharing and open access of DDE knowledge graphs. Meanwhile, it sets an example for other fields or domains’ knowledge graph integrating and sharing systems. Related Articles | Metrics | Comments（0）

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Research Progress and Prospect of the Tectonic Evolution of Okinawa Trough and Its Relationship with Magmatism, Hydrothermal Activities and Sedimentation LIU Wei，SUN Yujie，ZHENG Hanyue，XIN Mengran，HE Wei，WEI Tong，GUO Shiyue，CHEN Sifang,LIU Wenwen，FENG Yuge Acta Metallurgica Sinica    2020, 26 (6): 680-690.   DOI: 10.16108/j.issn1006-7493.2019084 Abstract （1334）      PDF（pc） （2313KB）（3887）       Knowledge map    Save The Okinawa Trough is a typical back-arc basin in the western Pacific Trench Arc Back-Arc system. Its unique tectonic location, magmatism, hydrothermal activities and sedimentary records have been a focus of academic research. Based on previous research, we review the controls of magmatic, hydrothermal and sedimentary activities by tectonic evolution of the Okinawa Trough. The subduction of the Philippine Sea plate led to the formation of the Okinawa Trough and the occurrence of arc volcanism, back-arc volcanism and cross-back arc volcanism. These three types of volcanism resulted in three different zones of hydrothermal activity. The magmatism and fault system caused by subduction of Philippine Sea plate provide heat sources and channels for the development of hydrothermal fluid in the Okinawa Trough. The subsidence of Zhe -Min Uplift at ~416 ka brought about the sediments in the northern Okinawa Trough to change from coarse-to fine-grained. Finally, we also provide the outlook of further research based on the current research status of the Okinawa Trough. Related Articles | Metrics | Comments（0）

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Macroscopic and Mesoscopic Investigation on the Physical and Mechanical Characteristics of Coral Limestone at Different Depths MA Linjian, LIU Huachao, ZHANG Wei, LI Qi, ZHU Honghu, WU Jiawen Geological Journal of China Universities    2023, 29 (3): 471-478.   DOI: 10.16108/j.issn1006-7493.2021074 Abstract （2587）      PDF（pc） （2519KB）（3809）       Knowledge map    Save In order to investigate the physical and mechanical characteristics of coral reefs with different depth in the South China Sea, scanning electron microscopy (SEM) and X-ray tomography (CT) technology are used to characterize the micro morphology and internal pore structure characteristics of shallow and deep reef limestone. Quantitative relationships between P-wave velocity and porosity as well as density were established. Uniaxial compression tests on dry and saturated reef limestone were also carried out. Results show that shallow reef limestone is porous with excellent pore connectivity, and the main mineral composition is aragonite, which belongs to the biological sedimentary rock. While deep reef limestone is dense with poor pore connectivity, and the main mineral composition is calcite, belonging to the metamorphic rock. The porosity of deep reef limestone is about 1/10, with an average peak compressive strength of about 4.8 times and an average elastic modulus of about 4.5 times that of shallow reef limestone. Reef limestone belongs to soft or extremely soft rock, characterized by brittle destruction property. The typical damage pattern is multiple rupture surface destruction along the primary pore, growing line of corals and weak bond surface, with high  residual strength. The hydrogenic effect of reef limestone is significant, and the water rationality of deep reef limestone is stronger than shallow reef limestone. The significant difference of physical and mechanical performances in shallow and deep reef limestone are mainly due to the variety in mineral components, pore structure and lithology caused by the varying degree of rock cementation with different depths. Related Articles | Metrics | Comments（0）

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Research of Full Dimension Monitoring Technology and Model Test of Slopes CHENG Gang, Zhang Haoyu, ZHU Honghu, SHI Bin, WU Jinghong Geological Journal of China Universities    2024, 30 (02): 207-217.   DOI: 10.16108/j.issn1006-7493.2023005 Abstract （1721）      PDF（pc） （5426KB）（3773）       Knowledge map    Save China is one of the countries with the most severe geological disasters, among which landslides are the most severe. Therefore, it is crucial to study landslide disasters deeply. Slope engineering is often affected by the superposition effect of human engineering activities and natural geological processes, which induce difficulty to scientific understanding of the slope deformation and instability mechanisms. To accurately grasp the slope state information, as well as the process of deformation and instability, a full-dimensional monitoring system is established to achieve dynamic interpretation and characterization of slope state information, thereby obtaining a more accurate, reliable, and intuitive basis for slope stability evaluation. In this paper, we comprehensively analyzes the‘air-space-ground-interior’integrated monitoring technology system of slopes from the perspectives of slope failure modes, typical slope monitoring technologies, and clarification of slope deformation evolution processes; Also, this study provides an overview and summary of the slope monitoring technology based on distributed fiber optic sensing (DFOS), with a focus on the research ideas and implementation paths of DFOS-based slope monitoring with multiple sources and fields. Further more, this study systematically reviews the process and results of physical model experiments of slopes based on typical monitoring technologies and DFOS technology, aiming to provide important reference for the design of slope reinforcement schemes and disaster prevention, mitigation and control. Related Articles | Metrics | Comments（0）

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Progress in Research on geochemistry of Tungsten MA Dong-sheng J4    Abstract （861）      PDF（pc） （789KB）（3735）       Knowledge map    Save China's tungsten reserves, production, consumption and volume of export all rank first in the world. China has been producing more than 80% of the total production in the world since 2000, and has preponderant influence in the nonferrous metal market of the world. Tungsten as an important strategic resource has found a wide utilization in modern life, industry, oil exploration, military equipments etc. The present paper reviews the progress in research on geochemistry of tungsten in last 20 years, including tungsten distributions in the solar system, in the earth and in the principal units and products from both endogenesis and supergenesis. The geochemical behavior of tungsten in magmas, hydrothermal fluids, supergenesis, and related effects on bionts, environment and health are also discussed. It is pointed out that the geochemistry of tungsten in its effects on environment and health is still a research gap in our country now. Special attention should be paid to this aspect of research. Related Articles | Metrics | Comments（0）

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FU Jian-Ming, MA Li-Yan, CHENG Shun-Bu, LEI You-Yue J4    2013, 19 (2): 202-.   Abstract （600）      PDF（pc） （1345KB）（3728）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Advances on Surficial Geochemistry Database and Related Research XU Yijiang, LI Chenglong, TAN Haolin, SHENG Xuefen Geological Journal of China Universities    2021, 27 (1): 58-72.   DOI: 10.16108/j.issn1006-7493.2021003 Abstract （1611）      PDF（pc） （2242KB）（3700）       Knowledge map    Save Surficial Geochemistry is an interdisciplinary study of the earth’s surface system, which is closely related to climate, environment, and human being. With the advent of the era of big data, surficial geochemistry is facing new opportunities and challenges. In order to provide reference for the construction of the big data platform of the Deep-Time Digital Earth Project (DDE), this paper conducts a preliminary investigation on the existing surficial geochemical data and databases. The results show that the surficial geochemical data have the characteristics of diversity and inter-disciplinal. Most data are lacking of standards and in an unstructured state; larger databases such as GEOTRACES and PANGAEA have relatively accepted data standards and data management experience; SISAL database has achieved key results in the task of data structuring; which are all worthy of further study. The works of surficial geochemistry big data science construction should be guided by research goals and needs, and by setting up corresponding scientific working groups as joined forces to promote the digitalization of surficial geochemistry discipline. Related Articles | Metrics | Comments（0）

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High Precision Analytical Method for Stable Strontium Isotopes CHEN Xuqi, ZENG Zhen, YU Huimin, HUANG Fang Geological Journal of China Universities    2021, 27 (3): 264-274.   DOI: 10.16108/j.issn1006-7493.2021031 Abstract （2693）      PDF（pc） （922KB）（3631）       Knowledge map    Save Because of the development of high-precision stable Sr isotope analytical method, stable Sr isotopes have been paid more attention in recent years. Great progress has been made in studies on supergene geochemistry, paleoenvironment, archaeology, endogenesis, and meteorites. This paper summarizes the key techniques of δ88/86Sr analytical methods. Ion exchange method with Eichrom Sr Specific Resin has been widely used to purify Sr. But this specific resin is expensive and may result in contamination during the chromatographic processes. Thus it could be replaced by cation-exchange resin. MC-ICP-MS and TIMS are the instruments for isotope measurement. Normally, MC-ICP-MS has higher measurement efficiency but slightly lower precision than TIMS. Standard-Sample-Bracketing method, Zr-Empirical-External-Normalization method, and double spike method are used to correct the instrumental mass bias. The Double Spike method may have relatively high measurement precision, but there are only a few studies using this method on MC-ICP-MS. Furthermore, there is no detailed comparison of δ88/86Sr of international standard materials. Therefore, optimizing the analysis process, improving the measurement precision, and more determination of δ88/86Sr of standard materials are necessary for the future studies of stable Sr isotopes. Related Articles | Metrics | Comments（0）

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Geology and Geomorphology of Tarim Basin and Its Evolution in the Cenozoic LI Jianghai，WUTongwen，LEI Yuting Acta Metallurgica Sinica

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Spatial-Temporal Distribution of Mesozoic Ore Deposits in South China and Their Metallogenic Settings MAO Jing-wen1, XIE Gui-qing1, GUO Chun-li1, YUAN Shun-da1, CHENG Yan-bo2, CHEN Yu-chuan1 J4    Abstract （1519）      PDF（pc） （5028KB）（3475）       Knowledge map    Save Based on extensive field investigation and precise geochronological data we proposed Mesozoic metallic mineralization in South China can be grouped into three pulses, i.e. Late Triassic (230~210 Ma), Mid-Late Jurassic (170~150 Ma), and Early-Middle Cretaceous (134~80Ma). The mineralization elements in these three pulses are different. The Triassic mineralization is Peraluminous granite-related W-Sn-Nb-Ta. The Mid-late Jurassic mineralization can be further divided into 170~160 Ma porphyry and skarn Cu and I-type granite-related Pb-Zn-Ag, and 160~150 Ma paraluminous granite-related polymetallic W-Sn. Although the Cretaceous mineralization lasted about 54 Ma, its peak ranged from 100 Ma to 90 Ma. The major types of the mineralization are epithermal Au-Ag-Cu and granite-related polymetallic tin (tungsten). The Triassic peraluminous granite-related W-Sn-Nb-Ta is a response to the post-collisional process of the South China plate with the North China plate. The Izanagi plate started to subduct beneath the Eurasian continent at ca. 180 Ma and then the porphyry copper deposits and vein type Pb-Zn-Ag deposits and their related I-type granitoids or aidakitic rocks formed when the subducted plate was teared up in several locations at 170~160 Ma.After then a big window occurred in the Nanling area, triggering the asthenospheric substance got into the upper crust so that developed large-scale high fractionation paraluminous granite and related polymetallic W-Sn mineralization. It was a relatively quiet period of 150~135 Ma in South China except for the Middle-Lower Yangtze River Valley area located in the northeastern margin of the South China plate. Because starting to change motion-direction to northeast the subucted plate was teared up along the Middle-Lower Yangtze River Valley which used to be a foreland basin of the Triassic Dabie-Sulu orogenic belt. A group of skarn-porphyry Cu-Mo-Au-Fe ore system and related I-type or aidakitic granites developed along the cross of the Middle-Lower Yangtze River Valley with the NE-trending faults at an age range of 145~135 Ma. From 135 Ma the subducted plate moved along several groups of regional-scale NE-striking fault zones comprising the Tan-Lu fault zone, which trigged the Eurasian continent to extensive extension. At the setting developed a lot of linear NE-trending Cretaceous faulting basins and metamorphic cores accompanied with volcanic rock eruption as well as epithermal Cu-Au-Ag ore system, granite-related polymetallic Sn (W) deposits and hydrothermal uranium deposits at age of 120~80 Ma with a peak of 100~90 Ma. Related Articles | Metrics | Comments（0）

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W-Sn-Nb-Ta-Bearing Granites in the Nanling Range and Their Relationship to Metallogengesis CHEN Jun, LU Jian-Jun, CHEN Wei-Feng, WANG Ru-Cheng, MA Dong-Sheng,ZHU Jin-chu, ZHANG Wen-lan and JI Jun-Feng J4    Abstract （1202）      PDF（pc） （3275KB）（3423）       Knowledge map    Save The large-scale mineralizations of W, Sn, Nb and Ta related to granites took place in the Late Jurassic period in Nanling Range, South China. According to the petrological and geochemical features of ore-bearing granites and their relationship to mineralizations, they can be grouped into the following three major types: W-bearing granites, Sn-W-bearing granites and Ta-Nb-bearing granites. The W-bearing granites show low TiO2 and Ba+Sr contents and LREE/HREE ratios,intensive Eu depletion, high Rb and Y abundances and Rb/Sr ratios, and oversaturation in Al. They commonly underwent intensive differentiation and evolution. The Sn-W-bearing granites are characterized by enrichment of TiO2, total REE, HFSEs,Ba+Sr and Rb, higher CaO/(K2O+Na2O) and LREE/HREE ratios, metaluminous-weakly peraluminous feature and lower Rb/Sr ratios, and weaker differentiation and evolation. The Ta-Nb-bearing granites have very low TiO2, Ba+Sr, total REE and HFSEs contents and CaO/(K2O+Na2O) ratios, higher Al2O3/TiO2 and Rb/Sr ratios, higher Rb and Nb contents, and ACNK values. They are highly evolved. Good discrimination can be obtained between these three types of W-Sn-Nb-Ta-bearing granites on plots employing Nb-Y-Ce, (Ba+Sr)-Rb-(Zr+Nb+Ce+Y), LREE/HREE-Rb/Sr and LREE/HREE-(Zr+Nb+Ce+Y) diagrams. These three types of ore-bearing granites have obviously different evolutional trends. Metallogenesis is intimately related to the evolution of the ore-bearing granites. Mineralizations of Sn, W or W-Sn and Nb-Ta or Sn-W-Nb-Ta are closely related to biotite granites, twomica granites or muscovite granites and albite granites respectively. The important deposit types of W, Sn, Nb and Ta and their major features in the Nanling Range are summarized in the paper. The chloritized granite type tin deposit is proposed. This paper indicates that an attention to searching for both the chloritzed granite type tin deposits and greisen-quartz vein type W-Sn deposits in W-Sn-bearing granites in the Nanling Range should be especially paid. Related Articles | Metrics | Comments（0） Cited: Baidu(96)

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Hainan Mantle Plume and the Formation and Evolution of the South China Sea YAN Quan-shu1,2 and SHI Xue-fa1 J4    Abstract （1379）      PDF（pc） （771KB）（3405）       Knowledge map    Save Seismic tomographic images obtained from the mantle under the southeast Asia region indicate there may exist a mantle plume beneath and around the Hainan island. A sub-vertical low-velocity column is imaged beneath the Hainan and the South China Sea, and extends from shallow depths to 660-km seismic discontinuity (i.e., the interface between upper mantle and lower mantle), and continuously to a depht of 1900 km. There is a large quantity of Cenozoic alkali basalts distributed in the South China Sea and its adjacent areas which include Leiqiong Peninsula, Hainan Island, Beibuwan Basin, Weizhou Island in Guangxi province and Indochina block. The geochemical data for these basalts show the characteristics of OIB-type basalt and DUPAL-like isotopic anomaly, and imply its deepseated origin. In addition, the average value of Tp (mantle potential temperature) for the South China Sea inferred from olivine-fluid equilibrium, is 1661℃, which is higher than that of MORB and lies between the corresponding values of Hawaii hotspot and Iceland hotspot. Based on evidences mentioned above, combined with numerical model experimental data, it shows that there does exist a mantle plume beneath the Hainan Island and adjacent areas. Until recently, scholars have developed many models about the formation and evolution of the South China Sea, and the debating issue is the geodynamic source. We suggest that the Hainan plume may be a significant geodynamical source for the formation and evolution of the South China Sea. Here the Hainan plume is introduced into our preliminary model about the formation and evolution of the South China Sea. The model is as follows: (1) 50-32 Ma, Integrated effects of collision between thd Indian Ocean plate and Euro-Asian plate resulted in retrogression of Pacific plate, created a extensional tectonic setting, and provided a channel for ascent of the mantle plume; (2) 32-21 Ma. When the head of mantle plume arrived at asthenosphere, it immediately interacted with the spreading center of the South China Sea by lateral material flow, which enhanced spreading spead. During 26-24 Ma, there took place a ridge jump, which adjusted the spreading center from nearby 18。N (i.e., present-day center of NW sub-basin) to nearby 15.5。N (i.e., present-day center of East sub-basin); (3) 21-15.5 Ma. With the mantle plume effect gradually enhancing, the hotspot-spreading center interaction became more and more intensive, and at about 21 Ma, there took place a ridge jump again, and induced the opening of SW sub-basin; (4) 15.5-0 Ma. Due to collision between the Indo-Australian plate and the Sunda continent, the spreading stopped. Subsequently, the earlier formed oceanic crust subducted along Nansha trench and Manila trench. However, the mantle plume still existed up to now. An actual evidence is: since the Pliocene a large amount of alkali basalt erupted in the South China Sea and its adjacent areas. Related Articles | Metrics | Comments（0） Cited: Baidu(63)

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Analyses of Current Main Geochronological Databases and Future Perspectives LI Qiuli, LI Yang, LIU Chunru, LU Kai, QIN Jintang, WANG Fei, WANG Tiantian, WANG Yinzhi, WU Liguang, YANG Chuan, YIN Gongming, LI Xianhua Geological Journal of China Universities    2020, 26 (1): 44-.   DOI: 10.16108/j.issn1006-7493.2019100 Abstract （1108）      PDF（pc） （8360KB）（3250）       Knowledge map    Save Geochronology, including absolute radio-isotopic dating and relative dating, is an essential subject of Earth sciences. We have seen significant advances in geochronology in the past century as demonstrated by the developments of theoretical systems, techniques, and analytical approaches, which facilitated both the quality and quantity of geochronology data. Within the suitable range of calibration, various dating methods could confirm each other, and the geochronology system becomes more accurate and explicit. For example, high-precision geochronological results and massive micro-analysis data provide time framework for geological events with unprecedented details. They lay the foundation for both quantifying the processes and rates of geological events and underpinning the coupled evolution of the Earth system. As a response to the dramatic increase of geochronological data, many databases for data management and sharing have been developed. The current paper summarizes the features of the existing geochronological databases, as well as advances in both high temporal and spatial resolution geochronology, to explore the opportunities and challenges of developing geochronology in the big data era. Related Articles | Metrics | Comments（0）

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Discussion on Genetic Classification of Metamorphic Ore Deposits SHEN Qi-han J4    Abstract （698）      PDF（pc） （634KB）（3235）       Knowledge map    Save This paper discusses the definition of the metamorphic ore deposits. On the basis of the preceding study, a new genetic classification scheme is tentatively put forward, in which 5 types and 13 subtypes are discriminated, and representative ore deposits examples are given for each type and subtype. The new classification is shown as follows. (1)Metamorphosed ore deposits, which are subdivided into five subtypes: the metamorphosed banded iron formation (BIF) sedimentary subtype, the metamorphosed BIF volcano–sedimentary subtype, the other metamorphosed sedimentary–volcano–sedimentary formation subtype, the metamorphosed igneous alteration ore deposits subtype and the metamorphosed spilite–keratophyric volcano–eruptive sedimentary ore deposits subtype; (2) Metamorphic ore deposits of regional metamorphism. Three subtypes are included: the metamorphic recrystallization subtype, the components recombination by metamorphic chemical reactions subtype and the metamorphic hydrothermal ore deposits subtype; (3)Metamorphic ore deposits of local metamorphism. Three subtypes are determined: the skarn ore deposits of contact–metasomatism subtype, the local thermal contact–metamorphic subtype and the local dynamo–metamorphic subtype;(4) Metamorphosed sedimentary–volcano–sedimentary ore deposits superimposed and transformed by metamorphic hydrothermal solutions; (5) Ore deposits by migmatism. Two subtypes are included: the migmatitic–metasomatic subtype and the later stage migmatitic–hydrothermal subtype. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Sensitivity Analysis of Rock Stress Wave Propagation and Attenuation Characteristics Based on MatDEM FAN Guansheng, HUANG Yehuan, LIU Chun, LE Tiancheng Geological Journal of China Universities    2023, 29 (3): 479-486.   DOI: 10.16108/j.issn1006-7493.2021102 Abstract （1426）      PDF（pc） （6972KB）（3226）       Knowledge map    Save The study of stress waves is a key issue in the dynamic action of rocks. Based on the discrete element method, this paper carries out numerical simulation tests on rock samples to explore the influence factors and laws of stress wave propagation and attenuation. The analysis focuses on the influence of the element radius, damping coefficient, incident wave frequency and amplitude on the stress wave propagation of the rock numerical sample, compares and analyzes the real test results. The research results show that the discrete element method can effectively simulate the dynamic process, and the variation law of the stress wave propagation in the numerical rock sample is consistent with previous studies. The increase in the radius of the rock sample unit will increase the unevenness of the rock sample and increase the scattering attenuation; the larger the damping coefficient, the greater the attenuation of the amplitude at the same distance; the frequency of the incident wave in the rock sample decreases, the wave propagation trend develops from logarithmic attenuation to linear attenuation; the greater the amplitude of the loading wave, the greater the attenuation of the stress wave due to scattering, and the attenuation rate at the same propagation distance remains constant.  Related Articles | Metrics | Comments（0）

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Characteristics of Cryptoexplosive Breccia from the Chating Copper-Gold Deposits, Xuancheng, Anhui Province and Its Metallogenic Significance XIE Qiaoqin，SUN Rui，XU Xiaochun，XU Xinyue，AN Yuhua，QIAN Shilong Acta Metallurgica Sinica    2020, 26 (3): 255-264.   DOI: 10.16108/j.issn1006-7493.2019045 Abstract （3438）      PDF（pc） （6839KB）（3223）       Knowledge map    Save The Chating copper-gold ore in Xuancheng region is a newly discovered large ore deposit in the Mesozoic-Cenozoic volcanic-sedimentary Nanling-Xuancheng basin in recent years, where the deposits are located at shallow depths of the Middle-Lower Yangtze River. This study is focused on the cryptoexplosive breccia pipe developed in the intrusives of quartz-dioriticporphyrite in the Chating copper-gold ore deposits. Based on the detailed core observations and petrographic analysis, characteristics and types of cryptoexplosive breccia are determined, and the relationship between the cryptoexplosive breccia and the copper-gold mineralization is discussed. The cryptoexplosive breccia in the ore deposits can be divided into three types: cryptoexplosivemelt-crystal-lithicbreccia, cryptoexplosive hydrothermal breccia, and cryptoexplosive fracture breccia based on its textures, compositions and abundance of rubbles. The cryptoexplosive breccia appears as an irregular pipe enveloped by the quartz-dioriticporphyrite and shows a regular spatial distribution. From the center of breccia to wall-rock are quartz-dioriticporphyrite, cryptoexplosivemelt-crystal-lithicbreccia, the cryptoexplosive hydrothermal breccia, and the cryptoexplosive fracture breccia, respectively. The spatial relationship between the alterated, mineralized and the cryptoexplosive breccia pipe shows that there exists a genetic link between formation of cryptoexplosive breccia and mineralization. The cryptoexplosion of the melt, liquid and gas originated from intermediate-acid magma induced the formation of large amount rubbles and fractures which can cause sudden temperature and pressure changes of ore-forming fluids. In addition, the cryptoexplosive breccia may provide room for migrating, mixing, and ore-forming material unloading for ore-forming hydrothermal fluid that arose from magmatic hydrothermal fluid. The geological features of the Chating copper-gold deposit are similar to those of the porphyry deposits including the intermediate-acid porphyrite host rocks, the alteration types, and zonation of wall rocks, as well as fine-grained dissemination and fine-veined, and net-veined mineralization. However, the mineralization enrichment site is consistent with the cryptoexplosive breccia pipe. Also, the geological features such as breccia, veined, agglomerated mineralization and hydrothermal anhydrite developed intensively in the vein are distinctly different from typical porphyry deposits. Therefore, based on these characteristics, we suggest that the Chating copper-gold ore deposit is a cryptoexplosive breccia type deposit closely related to intermediate-acidic hypabyssal intrusion. Related Articles | Metrics | Comments（0）

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Research Progress and Prospect of the Gangdese Magmatic Belt in Southern Tibet MENG Yuanku, YUAN Haoqi, WEI Youqing, ZHANG Shukai, LIU Jinqing Geological Journal of China Universities    2022, 28 (1): 1-31.   DOI: 10.16108/j.issn1006-7493.2020057 Abstract （2725）      PDF（pc） （2414KB）（3129）       Knowledge map    Save The Gangdese magmatic belt is the product of the northward subduction of the Neo-Tethys oceanic lithosphere beneath the Lhasa terrane and subsequent India-Asia collision. The Gangdese magmatic arc belongs to the typical continental magmatic belt and is the target area for studying plate accretion, crustal growth and reworking and collisional orogeny. Numerous lines of evidence indicate that the Neo-Tethys oceanic lithosphere experienced four distinct stages of evolution: the early-stage subduction (>152 Ma), late-stage subduction (100 to 65 Ma), main-collisional (55 to 40 Ma), and post-collision extentional stages (23 Ma to present). Multiple studies were carried out in the Gangdese belt and much progress has been made during past decades. However, the formation and evolution of the Neo-Tethys Ocean and magma source of igneous rocks are still debated, especially the detailed petrogenetic dynamic processes. This paper reviews the evolution history and tectonic background, and then summarizes related scientific problems from thirteen aspects. It is shown that the Gangdese magmatic belt is a typical magmatism-tectonismmineralization-deformational metamorphism belt and experienced multi-stage evolution processes rather than a simple continental magmatic arc aggregated in the Lhasa terrane. The review shows that (1) the Gangdese magmatic belt is a natural laboratory for studying the evolution history of the Neo-Tethys, and provides better constraints on the styles of the subducting slab. (2) The different-stage granitoid stocks and batholiths might be formed by multiple additions and incremental assembly of magmas over a span of millions of years or even longer. Therefore, we should use a mush model to reconstruct petrogenesis and petrogenetic secnarios of granitoid rocks in detail. (3) The mantle nature of the Gangdese region shows complicated features that are characterized by geochemical heterogeneity along the arc strike direction. (4) The reversed isotopes exist in the Gangdese belt, probably indicating an ancient nucleus. (5) The Gangdese belt is tilting and has different crustal compositions that are characterized by lower crustal compositions in the eastern segment and middle-upper crustal compositions in the middle-western segment. Crustal tilting of the Gangdese region suggests a differential and imbalanced exhumation process. (6) At present, numerous studies are focused on igneous rocks with methods mainly including radioactive Sr-Nd-Hf isotopes, whereas non-traditional stable isotopes (Mg-O-Li-B-Mo) are rarely reported. In addition, research topics are mainly associated with petrogenesis and geochronology, but few studies focus on the magma emplacement and post-magmatic deformation and uplifting-denudation processes. (7) Research in structural geology of the area is few and usually tectonic evolution is inferred from magmatic evolution in the Gangdese belt, southern Tibet. Finally, we also provide future prospects based on the current research status of the Gangdese magmatic belt in southern Tibet. Related Articles | Metrics | Comments（0）

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Magma Mingling: Evidence from Enclaves Wang De-zi J4    Abstract （1137）      PDF（pc） （857KB）（3086）       Knowledge map    Save The magma mingling between mafic magma and felsic magma is the primary mechanism responsible for the granitoids of crust-mantle mixed source. The dark colored, microgranular and igneous-texture enclaves provide reliable evidence that indicates the existence of magma mingling. These enclaves have the following characteristics: (1) the form of enclaves usually presents an equi-axed shape, which shows that enclave magma existed in the host magma with a globule liquid state; (2) since the temperature of basic magma is higher than acidic magma (temperature excess about 300℃), this type of enclaves often has quenched margin; (3) the enclaves sometimes contain back veins; (4) feldspar xenocrysts captured from the host magma can be seen in the enclaves. Three typical granitic complexes (Pingtan, Putuoshan, Huashan-Guposhan) containing dark colored microgranular enclaves are exemplified in this paper. The formation of dark colored microgranular enclaves can be explained by the injection of the basaltic magma from deep seated magma chamber toward hypabyssal acidic magma champer. Related Articles | Metrics | Comments（0） Cited: Baidu(52)