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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
    Abstract3437)      PDF (1109KB)(4417)       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.
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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
    Abstract1939)      PDF (2398KB)(1894)       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. 
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    Isolationand Sr 2+ MineralizationMediatedbyCarbonate MineralizationBacteria
    XU Fengqin, DAI Qunwei*, HOU Lihua, ZHAO Yulian, WU Qinqin, QIN Yonglian,
    J4    2015, 21 (3): 376-.  
    Abstract987)      PDF (1574KB)(1885)       Save

     Soil pollution has increasingly become a serious problem, especially by radionuclide pollution, and has attracted wide attention. Microbial remediation of radionuclide contaminated soil has been studied and proposed as a potential strategy. Because some microorganisms in soil can consolidate heavy metal to form mineralization, heavy metal inos can be removed from soil. A strain of carbonate mineralization bacterium was isolated from the soil and was used for the mineralization of Sr2+. The final removal rate of 1.0 g/ L and 0.5 g/L Sr2 + was as high as 98% and 99% , respectively. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses revealed that the mineralized product was strontium carbonate. It is suggested that indigenous bacteria can survive soil radionuclide toxicity and strontium ions could be mineralized as stable carbonate minerals, which indicates important practicability for radionuclide or heavy metal bioremediation. Also, the finding will provide new insights into carbonate biomineralization.

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    Genesis Process of the Cretaceous Daqushan Pluton in Zhejiang Province: Crystal-Melt Separation and Magmatic Recharge
    HE Chen, XIA Yan, XU Xisheng, QIU Jiansheng, XU Hang, ZHANG Zhi, ZHAO Sidi
    Geological Journal of China Universities    2023, 29 (5): 657-678.   DOI: 10.16108/j.issn1006-7493.2022018
    Abstract1185)      PDF (11167KB)(1053)       Save
    The models of trans-crustal magmatic system and crystal mush provide new insights into the study of Cretaceous magmatism in northeast China. The Daqushan pluton is located in the northeast of coastal Zhejiang and Fujian. It is mainly composed of K-feldspar granite with abundant melanocratic microgranular enclaves (MME) and is locally traversed by several mafic-intermediate dikes. A small outcrop of monzonite is exposed near the Chaotoumen. MME have a fine-grained texture with acicular apatites. Zircon U-Pb dating results show that the rock samples in the Daqushan pluton (including the K-feldspar granite, MME, monzonite, and mafic-intermediate dikes) crystallized at ~100 Ma. The K-feldspar granite are highly silicic (SiO2=68.45%-73.82%). While the miarolitic granite (DQS-7) without MME has the higher silica (76.27%), and its whole-rock geochemical and Sr-Nd isotope compositions are similar to those of coeval high silica granites (SiO2>75%) exposed around the Daqushan pluton. Daqushan K-feldspar granite bearing aggregates of plagioclase and K-feldspar exhibit“complementary”trace element geochemical characteristics with Daqushan miarolite and surrounding high silica granites. Further researches show that the Daqushan K-feldspar granite and miarolite were formed by felsic magma which originated from the partial melting of the ancient crustal basement and was recharged by mantle-derived magma. Such felsic magma underwent fractional crystallization and the extraction of high silica melt. Then, the residual silicic cumulate of the crystal mush and high silica melt crystallized and formed the Daqushan K-feldspar granite, miarolite and the surrounding coeval high silica granites. The mafic dikes of Daqushan are enriched in LILEs and depleted in HFSEs
    and are derived from the partial melting of the enriched mantle metasomatized by subducted dehydration fluids. The results of EPMA analyses indicate that the plagioclase in the K-feldspar granite and MME has a core-mantle-rim texture with low- An in the core (27-36, 25-41) and rim (17-32, 18-26) and relatively high-An in the mantle (28-57, 27-65). Integration of the element geochemical characteristics and Sr-Nd-Hf isotopic results, monzonite and intermediate dikes should be the product of magma mixing of mantle-derived mafic magma and felsic magma, while MME are the product of magma mingling of the two endmembers. The results of the Al-in-hornblende geobarometer show that the crystallization depth of MME is 1.8- 3.0 km, hornblende in monzonite develops core-mantle-rim texture, the crystallization depth of hornblende core and mantle is 17.0-21.2 km, and the depth of hornblende rim is 1.9-4.5 km. Based on the study of the origin and genetic relationships of K-feldspar granite, MME, miarolite, monzonite and mafic-intermediate dikes, and compared with the surrounding coeval high silica granites, this study establishes a model of trans-crustal magmatic systems for Daqushan pluton. The rollback of the subducting paleo-Pacific plate, the back-arc extension in the coastal area and the upwelling of the asthenosphere led to the underplating of the mantle-derived mafic magma, and further induced the partial melting of basement rocks in the lower crust to produce felsic magma. The continuous recharge and heating of mantle-derived magma favor the existence of long-lived melt-bearing regions in magma chambers, promoting magma differentiation and crystal-melt separation and thus forming two magma chambers with depths of 17-21 km and 2-3 km, respectively. K-feldspar granite, high silica granites, monzonite, MME and intermediate-mafic dikes were formed by magma mingling/mixing and crystal-melt separation in two connected magma chambers at different depths.
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    Genetic Types and Accumulation of Crude Oil in the Central Inversion Zone in the Liaoxi Depression, Bohai Sea
    TIAN Derui, NIU Chengmin, WANG Deying, GUO Tao, PAN Wenjing, GUO Longlong
    Geological Journal of China Universities    2021, 27 (4): 444-458.   DOI: 10.16108/j.issn1006-7493.2020093
    Abstract438)      PDF (1211KB)(1175)       Save
    The central inversion zone of the Liaoxi Depression is the enrichment area of high quality light crude oil in the Liaodong Bay exploration area. However, the genetic types, source and accumulation of crude oil have not been systematically studied. Based on the analysis and comparison of the biomarkers, three sets of effective source rocks of the Shahejie Formation were distinguished. The first, third and fourth members of the Shahejie Formation, are obviously different in the source of organic matter and sedimentary environment. It is confirmed that plankton is the main component of organic matter in the three sets of source rocks. The first member of the Shahejie Formation (E2s1) has the highest plankton content and the least terrestrial organic matter input. The content of dinoflagellate in the fourth member of the Shahejie Formation (E2s4) was significantly higher than that in the first and third members of the Shahejie Formation (E2s1, E2s3). Both E2s3 and E2s4 source rocks were deposited in the freshwater and weakly alkaline reducing environment, and the E2s1 source rock was deposited in the brackish to saline alkaline strongly reducing environment. The crude oil found in the central inversion zone can be divided into three source-related types through hierarchical cluster analysis(HCA). The oil-source correlation results show that the type Ⅰ crude oil is the mixed oil originated from the E2s3 and E2s1 source rocks, which is mainly distributed in the middle block and the middle area of the east block on the central inversion zone. The type Ⅱ crude oil is originated from the E2s4 source rocks, which is distributed in the southern area of the east block on the central inversion zone. The type Ⅲ crude oil is the mixed oil originated from the E2s3 and E2s4 source rocks, which is mainly distributed in the west block and the northern area of the east block on the central inversion zone. On this basis,

    the main controlling factors of hydrocarbon accumulation in the central inversion zone of the Liaoxi sag were analyzed. Oil and gas
    reservoirs on the central inversion zone are controlled by multiple factors, including the distribution of effective source rocks and the math of fault and sand bodies.

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    Predevonian Tectonic Evolution of South China: from Cathaysian Block to Caledonian Period Folded Orogenic Belt
    SHU Liang-shu
    Abstract2133)      PDF (501KB)(4297)       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.
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    The Quantitative Analysis Methods for Iron Oxides in Sediment and
    Their Application in Cretaceous Oceanic Red Beds
    LI Xiang, CAI Yuanfeng
    J4    2014, 20 (3): 433-.  
    Abstract846)      PDF (1087KB)(2467)       Save

    Hematite and goethite are the most stable iron oxides in nature and widely present in different compartments of the global
    system. They are responsible for the color origin of many types of sediment. In addition, the formation and preservation of hematite and goethite have been used to track palaeoenvironmental information. There are several approaches to characterizing and distinguishing hematite and goethite, but the quantifying of the concentrations of hematite and goethite in natural samples has been restricted by low concentration, relative poor crystalline and fine-grained as well as the limits of specific analysis methods used. In this paper, the most common quantitative methods of hematite and goethite, including X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS), have been introduced. Based on the qualitative analysis of the Cretaceous Oceanic Red Beds (CORBs) samples, we used the K-value method to quantify the hematite contents in the red shale samples from the Chuangde section in Tibet and obtained the hematite contents ranging from 3.81% to 8.11%. Analysis using DRS with multiple linear regression was performed to obtain the absolute contents of iron oxides within Aptian-Albian cyclic oceanic red beds in ODP Hole 1049C 12X Core, North Atlantic. The results reveal that the brown beds contain 0.13~0.82% hematite and 0.22~0.81% goethite. The orange beds contain 0.19~0.46% hematite and 0.29~ 0.67% goethite. The comparison of the calculated results with the test data shows that both methods were feasible for the quantitative analysis of iron oxides in CORBs. In actual practice, the accuracy of qualitative analysis of iron oxides must firstly be improved by the combination of XRD with DRS and then the choosing of quantitative analysis method can be achieved through the comprehensive analysis of both the predicted contents and crystalline of iron oxides.

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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
    Abstract1263)      PDF (7167KB)(699)       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.
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    Recent Advancement in Methods of Estimating Geothermal Reservoir Temperature: A U.S. National Geothermal Data System-based Study
    JIANG Shu, CHEN Guohui, ZHANG Yuying, ZHANG Luchuan, KUANG Jian, LI Chun, CHENG Wanqiang
    Geological Journal of China Universities    2021, 27 (1): 1-17.   DOI: 10.16108/j.issn1006-7493.2020096
    Abstract592)      PDF (2072KB)(1213)       Save
    Estimation of geothermal reservoir temperature plays a key role in the geothermal system research. This study employs geothermometers of geochemistry, mineral equilibria, mixing model with cold meteoric water, and gas to evaluate the reservoir

    temperature of different geothermal fields with data archived in the National Geothermal Data System (NGDS), which concludes the
    limitations of applications of different methods for determining the reservoir temperature and provides benchmarks for choosing the
    appropriate methods to calculate the geothermal reservoir temperature. The results reveal that: 1) The geochemical geothermometer
    method is reliable when the geothermal fluids reach the equilibrium between ions and minerals; the SiO2 (silica) geothermometer is more reliable than the cation geothermometer when the geothermal fluids have not reached the equilibrium; 2) The saturation index of the mineral equilibria can provide benchmarks choosing the geothermometers even if it cannot calculate the accurate reservoir temperature due to the selection of limited saturated minerals. For example, the chalcedony geothermometer is better than SiO2 geothermometer to estimate the reservoir temperature of due to the oversaturation of silica based on the multi-mineral equilibrium plot. For the vapordominated high temperature geothermal reservoirs, the minerals and ions cannot reflect the properties of geothermal reservoir, and the gas thermometer will be more successful in predicting the subsurface temperature in high-temperature geothermal systems. The mixing models usually overestimate the reservoir temperature since they pick up the temperature before the hot water gets mixed with the cold water. There is no universal geothermometer since each method has its own assumptions and works for specific geothermal setting. The best approach is to employ various suitable geothermometers and validate the results.

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    Classified Evaluation of Shale Reservoirs in the Ordovician Wufeng to Silurian Longmaxi Formations in the Southern Sichuan Basin
    GUO Jianlin,JIA Chengye,HE Dongbo,LI Lin,ZHU Hanqing,ZHOU Yi,LIU Chang
    Acta Metallurgica Sinica    2020, 26 (3): 323-332.   DOI: 10.16108/j.issn1006-7493.2019047
    Abstract590)      PDF (4500KB)(1031)       Save
    On the basis of resource evaluation and favorable area evaluation, this paper established a set of classified evaluation criteria for shale reservoirs in the Wufeng-Longmaxi Formations in the southern Sichuan Basin. The criteria for effective reservoir identification include porosity (Φ) greater than 3%, gas saturation (Sg) higher than 30%, density of rock matrix (DEN) below 2.7 g/cm 3, brittleness index (BI) over 40% and gas contents (Vt) higher than 1 m 3/t. These criteria can distinguish the reservoirs and non-reservoirs. Based on the conception of geological and engineering integration, gas contents (Vt) has been selected to characterize the resource foundation of shale reservoirs, which is positively correlated with porosity and organic matter abundance. The brittleness index (BI) positively correlating with siliceous and carbonate contents has been selected to characterize the compressibility. Gas contents and brittleness index can comprehensively characterize the geological and engineering characteristics of reservoirs. Effective shale reservoirs have been further divided into three types: Type I with gas contents over 4 m 3/t and brittleness index greater than 50%; Type II with gas contents lower than 4 m3/t or brittleness index less than 50%; Type III with gas contents from 1 m 3/t to 4 m3/t and brittleness index between 40%-50%. Reservoirs in the Wufeng Formation and the low member of the Longmaxi Formation have a good quality which mainly consist of Types I and II and locally Type III. According to the criteria established in this paper, evaluations for reservoir quality of horizontal drillings have been conducted, and correlations between penetration rate of Type I reservoir, testing production and estimate ultimate recovery (EUR) are positive. Horizontal wells with drilling efficiency of Type I reservoir over 50% have probability of 92% for testing production over 15×104 m3/d and the corresponding EUR exceeding 8000×104 m 3, meeting the requirements of economic development.
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    Progress of Methods for Assessing CO 2 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
    Abstract2089)      PDF (1109KB)(667)       Save
    CO 2 geological storage is an important technology to reduce CO 2 emissions, which can safely store CO 2 in geological formations for millions of years. Conventional CO 2 storage reservoirs include deep saline aquifers and depleted oil and gas reservoirs. Basalt is a new type of CO 2 storage reservoir that has been attracting attention in recent years. CO 2 storage in basalt would increase the technical method and potential of CO 2 geological storage. Storage potential assessment is one of the fundamental works of CO 2 geological storage study. This paper systematically examines the current methods for assessing the storage potential of CO 2 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 CO 2 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 CO 2 in basalts. ③Pore filling storage potential assessment method, which evaluates the proportion of secondary minerals that can fill reservoirs’ pore space after CO 2 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.
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    A Review of the Establishment Methods of Training Image in Multiple-point Statistics Modeling
    WANG Mingchuan, SHANG Xiaofei, DUAN Taizhong
    Geological Journal of China Universities    2022, 28 (1): 96-103.   DOI: 10.16108/j.issn1006-7493.2020049
    Abstract761)      PDF (1268KB)(874)       Save
    Multiple-point statistics (MPS) modeling has been the research hotspot of reservoir modeling technology in recent years, and its practicability is restricted by training image. The quality of training image determines the accuracy and reliability of MPS modeling, and is a key factor for the successful application of MPS modeling. This study addresses the characteristics and significance of training image, and systematically introduces the establishment methods of training image creation from the definition, usage and instance, etc., including hand drawn, object-based simulation, 3D seismic information extraction or transformation, prototype- ased model, process-based simulation and 2D image method. Then, our study comprehensively compares the data sources, advantages and disadvantages of various training image creation methods, and discusses the problems caused by MPS modeling relying on training images. Combined with reviewing prior works and MPS modeling practice, the research direction of training image and its establishment methods in the future is pointed out, which provides reference for MPS modeling researchers and users, and provides some thoughts for improving MPS modeling methods.
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    Geology and Geomorphology of Tarim Basin and Its Evolution in the Cenozoic
    LI Jianghai,WUTongwen,LEI Yuting
    Acta Metallurgica Sinica   
    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
    Abstract1976)      PDF (4975KB)(1448)       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.
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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
    Abstract683)      PDF (2414KB)(1114)       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.

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    Review on Application of Microbially Induced Carbonate Precipitation (MICP) for Soil Stabilization
    ZHOU Yingzheng, GUAN Dawei, CHENG Liang
    Geological Journal of China Universities    2021, 27 (6): 697-706.   DOI: 10.16108/j.issn1006-7493.2020116
    Abstract793)      PDF (1454KB)(812)       Save
    Microbial mineralization is a recently developing new branch in engineering of soil improvement that deals with the application of microbiological activity to improve characteristics of soils. One of the most commonly adopted processes to achieve soil bio-cementation is through microbially induced carbonate precipitation (MICP). This technique utilizes the metabolic behavior of urease bacteria to induce calcite that binds the loose soil particles integrally, leading to increased mechanical properties of soils. This paper systematically introduces the study of MICP about mineralization mechanism of urease bacteria, relative treatment methods, influencing factors, derived new technique (EICP) and relative field trials in geotechnical engineering. The practicability of the MICP is summarized. Finally, the challenges and potential solutions of MICP engineering applications in the current research stage are briefly discussed.
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    Status and Advances of Research on Caprock Sealing Properties of CO 2 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
    Abstract1626)      PDF (6425KB)(654)       Save
    CO 2 Geological storage is one of the key technologies to address global climate changes and reduce greenhouse gas emissions. Large-scale CO 2 injection into the formation is prone to inducing CO 2 leakage problem. In particular, the leakage problem of CO 2 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 CO 2 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 CO 2 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 CO 2 injection are illustrated, and some insight into the shortcoming of caprock seal is provided.
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    Grain-size Characteristics and Environmental Implication of Neogene Red Clays in the Chinese Loess Plateau
    LU Keke, CHEN Zhong, YANG Yanpeng, ZHANG Jialin, ZHAO Zhongqiang, XIA Dinghong, NI Chunzhong, SONG Yinxian, ZHANG Shitao
    Geological Journal of China Universities    2023, 29 (5): 713-725.   DOI: 10.16108/j.issn1006-7493.2022020
    Abstract190)      PDF (1237KB)(549)       Save
    The aeolian origin of red clays in the Loess Plateau has been unanimously recognized. The earliest red clay was found in the late Oligocene and early Miocene, indicating that the arid environment had been formed in the inland northwest of China at the end of Paleogene. The grain size characteristics of red clay in the loess plateau show that the average grain size gradually decreases from the north to the south, indicatin g that the initial monsoon system has been established, and the winter wind played an important role in the transport of aeolian dust. The grain size distribution of red clay indiactes that it is composed of two components. The coarse grain (>20 μm) represents those transported by the near surface wind (winter wind), while the fine grain (<5 μm) represents those transported by the upper westerly wind. The grain size composition characteristics of red clays well record the development and change of atmospheric circulation. Since the end of Oligocene, the average grain size and sedimentation rate of red clays in the west of Liupanshan Mountain increased at 21.3-20.2 Ma, 16.0-13.3 Ma and 8.7-6.9 Ma, which may be related to global cooling and the Qinghai-Tibet Plateau uplift, and the 8.7- 6.9 Ma increase was mainly controlled by global cooling. In the red clay section to the east of Liupanshan, the grain size of variation characteristics shows that the grains deposited during 7.6 Ma to 6.2 Ma or to 5.4 Ma is coarse, indicating that the winter monsoon was strong. After that, the average particle size was fine up to 3.6 Ma, and the deposition rate was low, indicating that the winter monsoon was weak climate environment. From 3.6 Ma to 2.6 Ma, most profiles show an increase in mean grain size, an increase in sedimentation rates, and an increase in both winter and summer monsoon, which indicates to the transition to Quaternary glacial period. The development of the Arctic ice sheet and the uplift of the Qinghai-Tibet Plateau may have contributed to these changes.
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    Marine Redox Fluctuation during the Early Cambrian Age 10: Evidence from U Isotopes
    QIU Chen, WEI Guangyi, MIN Siyu, CHEN Xi, LING Hongfei
    Geological Journal of China Universities    2022, 28 (1): 40-50.   DOI: 10.16108/j.issn1006-7493.2020038
    Abstract562)      PDF (2251KB)(800)       Save
    The marine animal diversity was generally low during late Cambrian and early Ordovician. Biogeochemical studies suggest that it may have been related with fluctuations in oceanic redox conditions, despite still lack of evidence. Well-preserved marine carbonates could record the geochemical characters of ancient seawater, and their uranium isotope compositions (δ238U) can be used to reconstruct the global oceanic redox conditions. In this study we analyzed the uranium isotope compositions of marine carbonates of the basal Cambrian Stage 10 from Wa’ergang section, South China. Our data show that the δ238U profile has three negative excursions with minima of -0.8‰ , -0.55‰ and -0.60‰ , respectively, which indicates three intervals of oceanic anoxia expansion. Modeling results based on the uranium isotope mass balance model suggest that about 22%, 3.5% and 5% of the global sea-floor were covered by anoxic water during these three intervals, respectively. We speculate that the first anoxic interval may have been related with increase in primary productivity due to enhanced weathering input of nutrients, and the latter two may have been induced by upwelling of deep anoxic water during the transgressions.
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    Chloritization Sequences in Mudstone during Diagenesis and Its Geological Significance
    FU Yu, DING Qingfeng*, WU Changzhi
    Acta Metallurgica Sinica   
    The Petrogenesis of Baishuizhai Granitic Pluton and Its Significance to Uranium Mineralization in the Xiazhuang Area, Guangdong Province
    LI Kun, CHEN Weifeng, GAO Shuang, SHEN Weizhou, HUANG Guolong, LIU Wenquan, FU Shuncheng, LING Hongfei
    Geological Journal of China Universities    2023, 29 (4): 497-513.   DOI: 10.16108/j.issn1006-7493.2021117
    Abstract341)      PDF (2375KB)(535)       Save
    The Baishuizhai pluton is one of the main ore-bearing wall rocks of the Zutongjian uranium deposit in the northwestern part of the Xiazhuang granite-related uranium ore filed, yet its petrogenetic mechanisms and its relationship with uranium mineralization are still unclear. Thus, in this study, we present zircon SHRIMP U-Pb ages, whole-rocks and mineral geochemical data for the Baishuizhai granite. Field and petrographic investigations show that the Baishuizhai granitic pluton was emplaced into the Xiazhuang granitic batholith, mainly composed of fine-grained two-mica granite and muscovite granite, and the zircon SHRIMP U-Pb dating reveals that both granites were formed during the Indochina period with ages of 229.4 Ma and 231.8 Ma, respectively. They show typical peraluminous S-type granitic geochemical characteristics that are high SiO 2 contents, total alkalis contents and ACNK values ( ≥ 1.1), low FeOt+MgO+TiO 2 contents and P 2O 5 contents, enriched in Rb, Th and U, depleted in Ba, Sr, P and Ti, and enriched in aluminum-rich minerals. Compared with the Xiazhuang granite, both types of granites in the Baishuizhai pluton show enriched in inherited zircon, higher SiO 2 contents and Rb/Sr ratios, but lower FeOt+MgO+TiO 2 contents, P 2O 5 contents, Zr/Hf ratios, and Fe 2+/(Fe 2++Mg) ratios of biotites, indicating that they were derived from low partial melting of reducing material-rich feldspathic meta-pelites, and are not formed by the differentiation evolution of the parent magma of the mafic meta-pelites-derived Xiazhuang granite. Furthermore, compared with the two-mica granite, the muscovite granite display significant tetrad REE patterns, lower REE, Zr/Hf ratios and Eu/Eu* values, indicating that an interaction of F-rich fluids with the magma occurred in the formation of the muscovite granite. Both types of granites in the Baishuizhai granitic pluton are enriched in uranium and can be important uranium-bearing granites in the region. Relative to the 2-mica granite in the Baishuizhai pluton, the muscovite granite is more enriched in uranium and more favorable to be uranium source rocks for hydrothermal uranium mineralization.

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    Paleogeographic Reconstruction Driven by Big Data: Challenges and Prospects
    ZHANG Lei, ZHONG Hanting, CHEN Anqing, ZHAO Yingquan, HUANG Keke, LI Fengjie, HUANG Hu, LIU Yu, CAO Haiyang, ZHU Shengxian, MU Caineng, HOU Mingcai, JAMES G. Ogg
    Geological Journal of China Universities    2020, 26 (1): 73-.   DOI: 10.16108/j.issn1006-7493.2019091
    Abstract546)      PDF (1094KB)(864)       Save
    Paleogeography is a typical data-reliable subject. Paleogeographic reconstruction focuses on the characteristics of geographic, life, and climate changes on the Earth's surface through geological history. In the new era of big data, the continuous accumulation of massive paleogeographic data and the rapid development of computer science technology make it possible to reconstruct the paleogeographic history using more standard and intelligent tools and software. The current paper reviews the major databases and research groups related to paleogeography, and proposes the following key components of big data-driven paleogeographic reconstruction: (1) A standard paleogeographic knowledge system; (2) An open and interactive paleogeographic data platform with new technologies such as natural-language understanding to expand data sources; (3) Paleogeographic data quality control mechanisms; (4) Various types of paleogeographic reconstruction models contructed with artificial intelligence technology; (5) Visual outputs as time-sliced maps or animations.
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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
    Abstract1137)      PDF (2519KB)(532)       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.

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    Influence of Subducting Plate Dynamic Properties to Flat-slab Subduction by Numerical Modeling
    ZHU Zhiyuan, WU Benjun
    Geological Journal of China Universities    2021, 27 (2): 240-248.   DOI: 10.16108/j.issn1006-7493.2019110
    Abstract476)      PDF (1886KB)(767)       Save
    This particular phenomenon of flat-slab subduction mainly occurs in South American, which is closely related to the structural geological phenomena such as earthquakes and volcanoes in this area. However, mechanics of flat-slab subduction is not yet
    well understood. By numerical modeling, we investigate influences of subducting plate dynamic properties to the geometry of flat-slab subduction. The model results show that subducting plate thickness and density contrast between slab and mantle have great impacts to flat-slab formation. The appropriate slab thickness (around 70 km) facilitate slab flattening, while thicker slab is difficult to bend and hesitates to flatten. The smaller the density anomaly of subducting plate, the easier slab flattens and the longer flab-slab length. When density anomaly is very large, no flat-slab is predicted. In addition, strong plate promotes flat-slab formation. Flat-slab length increases with plate viscosity increasing. We also find that trench rollback velocity decreases during the slab flattening episode. Our reference model REF_MODEL has comparable flat-slab geometry with central Chile subduction, which provides the insight of flat subduction formation in this area.
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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
    Abstract688)      PDF (2242KB)(1181)       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.
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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
    Abstract638)      PDF (2313KB)(1001)       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.
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    SedimentaryEnvironmentandMineralizationMechanismofthe StromatoliticPhosphoriteintheEdiacaranDengyingFormation, Weng′anCountyofGuizhouProvince,China
    ZHANG Wei, YANG Ruidong*, MAO Tie, REN Haili, GAO Junbo, CHEN Jiyan
    J4    2015, 21 (2): 186-.   DOI: 10.16108/j.issn1006-7493.2
    Abstract1335)      PDF (3299KB)(1733)       Save

     Stromatolitic phosphorite in the Ediacaran Dengying Formation was initially discovered in Weng′an-Fuquan area of SouthwesternGuizhouProvince,Chinawherephosphateoresarewidelydistributed.Asanewphosphorousstratumofphosphorite,itis characterizeddominantlybytypicalstromatoliticstructures.ThephosphoriteofstromatoliteislocatedatthetopoftheEdiacaran DengyingFormationthatiscomposedoflenticularorganicreef(algalreefofstromatolite).Themajormineralcomponentsofthe stromatoliticphosphoritearephosphatesandcarbonates.Thewhitelaminatedbedsareenrichedinphosphatemineralswhilethedark laminatedbedshavelowercontentsofphosphatemineralsandcontainmainlycarbonateminerals.Analysisofthemineralogicaland geochemicalcharacteristicsindicatesthatstromatoliticphosphoriteintheEdiacaranDengyingFormationisalgalreefofstromatolite thatwasformedinasemi-restrictedsubtidalenvironment.Accordingly,itcouldbeinferredthatthephosphoriccolumnarstromatolitic reefswereformedbyenrichmentinandprecipitationofphosphorusfromtheseawaterwithrichphosphorusduetocomplexbiological orbio-chemicalactionsofalgae.Inaddition,theresultsshowthatthemineralizationofphosphaticmineralsoccurredmainlyatthe sediment-waterinterfaceinweaklyalkalineandsuboxicenvironmentwherealgaehadplayedasignificantrole.

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    Petrogenesis of Ophiolite-type Chromite Deposits in China and Some New Perspectives
    HU Zhenxing, NIU Yaoling, LIU Yi, ZHANG Guorui, SUN Wenli, MA Yuxin
    J4    2014, 20 (1): 9-.  
    Abstract931)      PDF (1391KB)(1979)       Save
    Ophiolites of varying ages are widespread in China, some of which contain chromite deposites of industrial value. However, compared with some of the world’s large ophiolite chromite deposites (e.g., Kempirsai, Bulquiza, Guleman), the Chinese chromite deposits are small (e.g., Sartohay, Dongqiao, Luobusa). Recent research recognizes that most ophiolites with significant chromite reserves are all formed in a surpasubduction zone environment. Melt-rock interaction is a popular interpretation for the origin of podiform chromite deposits, but the actual mechanism in this model for chromite enrichment remains unclear. It remains the primary task to understand process or processes of chromium enrichment towards the formation of chromite deposits. Is the formation of chromium-rich melts necessary? If so, when, where, how, and under what conditions could this take place? These are additional processes beyond the well-understood aspects of the petrogenesis that need to research towards an effective chromite mineralization model.
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    Cited: Baidu(3)