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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 （5328）      PDF （1109KB）（5889）       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

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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 （2980）      PDF （2398KB）（2610）       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

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Predevonian Tectonic Evolution of South China: from Cathaysian Block to Caledonian Period Folded Orogenic Belt SHU Liang-shu J4    Abstract （2307）      PDF （501KB）（4951）       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

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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 （2629）      PDF （4975KB）（2124）       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

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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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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-.   Abstract （1025）      PDF （1391KB）（2559）       Knowledge map    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. Related Articles | Metrics Cited: Baidu(3)

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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-.   Abstract （904）      PDF （1087KB）（2828）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （564）      PDF （1211KB）（1400）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （2027）      PDF （6425KB）（1104）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （1784）      PDF （1237KB）（862）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （2473）      PDF （1109KB）（1090）       Knowledge map    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. Related Articles | Metrics

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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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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 （1503）      PDF （2519KB）（978）       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

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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 （1861）      PDF （2414KB）（1512）       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

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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 （2184）      PDF （436KB）（3953）       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

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Types and Characteristics of Geoheritage Resources in the Shungeng Mountain, Huainan, Anhui Province ZHANG Zikang, GU Chengchuan, WU Jiwen, ZHAO Ming, ZHAN Run, SHAO Qingqing, ZHANG Yuanyuan Geological Journal of China Universities    2024, 30 (01): 89-99.   DOI: 10.16108/j.issn1006-7493.2022063 Abstract （284）      PDF （4598KB）（695）       Knowledge map    Save The Shungeng Mountain in Huainan, Anhui Province, is tectonically located in the southern thrust-napped belt of the Huainan Coalfield within the North China Craton (NCC) and hosts many natural and artificial exhumed geoheritages. According to the field geological survey, 62 major geoheritage sites have been identified in the Shungeng Mountain, which can be divided into 3 major categories, 8 categories and 14 subcategories. Among them, typical Cambrian-Ordovician sections of the NCC, karst topography, fault structures and mining heritages are well developed and are of high scientific research and ornamental value. Based on the previous studies, the genesis and regional geological background of these geoheritages in the Shungeng Mountain are discussed, which provide a theoretical basis for the proper exploitation of the geoheritage resources. In light of the problems existing in the protection and exploitation of geoheritage resources in the Shungeng Mountain, this paper puts forward suggestions for long -term planning. Related Articles | Metrics

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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 Abstract （671）      PDF （1094KB）（1163）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （1870）      PDF （2375KB）（817）       Knowledge map    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. Related Articles | Metrics

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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 （1569）      PDF （922KB）（1237）       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

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3D Digitization of Geological Outcrops and Specimens：Status and Prospects XU Qi, SHEN Hanxiao, DONG Shaochun, SHI Yukun, FAN Junxuan Geological Journal of China Universities    2023, 29 (3): 403-418.   DOI: 10.16108/j.issn1006-7493.2022092 Abstract （1017）      PDF （3613KB）（864）       Knowledge map    Save In the era of big data, the high techniques such as knowledge graph, artificial intelligence and virtual simulation rapidly developed, and as a result the research methods of geosciences are evolving with the times. Compared to the traditional two-dimensional images and texts, three-dimensional digital models can provide more diverse data, and therefore hold enormous potential for both the scientific research and technology fields. The digitization of geological outcrops and specimens are two typical cases of 3D modeling technology in geoscience. This paper investigated the construction of digital outcrop and 3D specimen digitization, introduced the common digitization technologies, data sharing and development services, and the current representative digital geological outcrop and 3D specimen database. The investigation results were summarized and analyzed. Moreover, some problems that exist at present were summarized, and the future development was prospected in terms of data construction standard specification, construction content and function expansion. Related Articles | Metrics

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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 （944）      PDF （2242KB）（1532）       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

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Igneous Petrotectonic Assemblages and Tectonic Settings: A Discussion DENG Jin-fu1, 2，XIAO Qing-hui 1, 2，SU Shang-guo1, 2，LIU Cui1，ZHAO Guo-chun1，WU Zong-xu1，LIU Yong1，2 J4    Abstract （4010）      PDF （962KB）（4224）       Knowledge map    Save This paper discusses igneous petrotectonic assemblages of various tectonic settings: 1. mid–ocean ridge spreading; 2. oceanic island; 3. island arc; 4. MORS–type and SSZ–type ophiolites; 5. active coutineutal marginal arc; 6.compositional polarity of subduction–related magmatic arcs; 7. continental collision; 8. continental rift; 9. stable craton or platform, etc. It is emphasized that the tholeiitic ( TH ), calc–alkaline ( CA ) and alkaline ( A ) series defined from various parameters by different authors have different scientific meanings. In this paper it is indicated that the same written terms of TH, CA and A but with various meanings could easily result in abuse of these terms, especially for the recognition of the tectonic settings. The difference between MORS – and SSZ –type ophiolites in terms of igneous petrotectonic assemblages is discussed. The lowest MgOwt% of the HMA is suggested ( Table 2 ), based on the data of petrological experiments. The terms of magnesian andesite–dacite and adakite are discussed, and in turn, the Kay's magnesian andesite–dacite of higher Sr/Y, lower FeO/MgO, and higher MgOwt% as well as higher Ni, Cr contents, are comprehensively used, which can be more satisfactory to define the slab–melt, rather than the single parameter of high Sr/Y. The various schemes of classification for the continental collision are indicated, and it is necessary to be careful for using these schemes. The post–orogenic and the continental rifting A type granites are suggested to be associated with or without the CA/r, respectively, and the meaning of A and CA, here, is determined by the Peacock's alkali–lime index. Related Articles | Metrics Cited: Baidu(89)

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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 （1461）      PDF （7167KB）（1028）       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

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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 Abstract （649）      PDF （1886KB）（1089）       Knowledge map    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. Related Articles | Metrics

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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 （1068）      PDF （2571KB）（1307）       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

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Advance in Laser Raman Spectroscopy Carbon Geothermometer and Its Application in Earth Sciences CHEN Yiyi, WANG Bo, LIU Jiashuo, LU Shenghua, COCHELIN Bryan Geological Journal of China Universities    2023, 29 (6): 908-923.   DOI: 10.16108/j.issn1006-7493.2021116 Abstract （221）      PDF （1310KB）（645）       Knowledge map    Save Organic matter is usually enriched in sediments, and will be transformed from disordered carbonaceous material to fully-ordered crystalline graphite, after being buried and heated to some high temperature during metamorphism. The crystalline order is closely corresponding to the certain temperature condition of metamorphism. The Raman spectroscopy (RS) can reflect the vibrational modes of molecules of carbonaceous material (CM), and to reveal the crystalline degrees of graphite, and thus the metamorphic conditions. The RSCM method is an empirical geothermometer by obtaining and analyzing the Raman parameters like band position, peak intensity, band area and FWHM (full width at half maximum) of carbon or graphite grains from a series of metamorphic samples, whose metamorphic temperatures are already known or can be calculated by other methods. A close correlation between the RSCM and peak metamorphic temperature is very well defined, so as to quantitively calculate the peak temperature of the unknown samples during regional or contact metamorphism. Based on the comparisons with the traditional geothermometers, it is suggested that the RSCM is practicable and reliable, and it shows several advantages such as high efficiency, in situ and nondestructive measurements, wide range of temperature detection, high sensitivity to CM inner structures, being free from later retrograde metamorphism, and wide fields of application. Thus, this method is significant for the reconstruction of regional tectonic and thermal evolution, and crustal thermal state. This paper reviews the study history of the RSCM, introduces the theory on CM Raman spectrum band distribution and its relationship with metamorphic temperature, summarizes some representative studies of natural graphitic carbons by Raman spectroscopy in recent years, and its applications in different fields of Earth Sciences. The research foreground of RSCM is finally prospected. Related Articles | Metrics

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Research on the Control of CBM Well Reservoir Geological Engineering Characteristics on Productivity LI Quanzhong, SHEN Jian, HU Haiyang, JI Xiaofeng Geological Journal of China Universities    2023, 29 (4): 644-656.   DOI: 10.16108/j.issn1006-7493.2021118 Abstract （219）      PDF （711KB）（752）       Knowledge map    Save In order to improve the single well gas production of CBM well，the influencing factors of CBM well gas production are studied from the geological static parameters and engineering dynamic parameters of CBM development. Based on a block of Shanxi Qinshui Basin 12 reservoir parameters and geological characteristics of typical CBM Wells and development data， starting from the geological control factors, engineering control, detailed analysis of seven aspects of 24 kinds of factors, including coal bed methane resource characteristics，coal reservoir seepage characteristics，structures，energy，drilling，fracturing，drainage，we study the degree to which these factors control the CBM gas production. The results show that the gas production of CBM Wells in the same block is different, which is affected by both geological factors and engineering factors; Also, coalbed methane resources and coalbed methane reservoir seepage, structures and energy characteristics clearly influence coalbed methane production, and when the permeability of coalbed methane reservoir is more than 0.7 mD，it is favorable for coalbed methane well to yield increased gas production. In addition, faults affect the gas content of coal reservoir and fluid migration in the process of drainage and production. In the development of CBM, faults should be avoided and a safe distance of 400 m should be maintained. Furthermore, the higher the casing pressure and gas release pressure of CBM well，the more conducive to expanding the desorption radius of coal reservoir, which results in high and stable production of a CBM well. The scale of fracturing operation in coal reservoir also has great influence on gas production, and the scale of fluid injection is more significant than that of sand injection in the study area. The pressure drop rate and gas production rising rate should be reasonably controlled in each stage of CBM well, and the pressure drop rate should be controlled within 10 kPa/d in the pressure control and production raising stage. These will allow to enlarge the pressure drop funnel radius of Coal Reservoir. The analysis of the geological and engineering factors of CBM Wells in the study area provides a theoretical basis for the geological selection and geological selection of CBM. It may also serve as technical guidance for the development of other CBM projects.  Related Articles | Metrics

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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 Abstract （987）      PDF （1268KB）（1191）       Knowledge map    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. Related Articles | Metrics

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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 Abstract （771）      PDF （2072KB）（1499）       Knowledge map    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. Related Articles | Metrics

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Structural Characteristics and Deformation Mechanisms of Multipledetachments in Luzhou area, Southeastern Sichuan Basin ZHAO Shengxian, XU Wenqiao, YANG Xuefeng, YIN Hongwei, LI Bo, WANG Wei, ZHANG Chenglin, JIA Dong, LIU Yongyang, XIE Wei, ZHANG Dongjun, LI Changsheng Geological Journal of China Universities    2023, 29 (5): 726-734.   DOI: 10.16108/j.issn1006-7493.2022029 Abstract （1140）      PDF （7113KB）（691）       Knowledge map    Save In recent years, shale gas exploration and development in southeastern Sichuan has gradually expanded to the deep areas. The Luzhou area shows great potential of shale gas exploration and development with the depth over 3500 m. In order to further clarify the characteristics and evolution mechanism of various structural deformation in Luzhou area, the main controlling factors of fold belt were explored by using discrete element numerical simulation based on structural analysis of seismic data, and the evolution process of Mesozoic and Cenozoic was restored. And the following research results show that multiple detachment layers and regional tectonic compression are the main controlling factors of structural deformation in Luzhou area. Influenced by multiple detachment layers, Luzhou area has developed low steep thin-skinned structure and obvious vertical stratification, forming complex structure such as fault-propagation folds, detachment folds, buried folds and duplex structures between detachment layers. Among them, the lower Cambrian gypsum rock plays a major role in controlling the deformation, and the gypsum rock and shale slippage coordinate and accumulate towards the core of the anticlines. Since the late Yanshanian, the multi-detachment allochthonous succession with regional compression in Luzhou area were developed the thin-skinned comb-shaped folds. The fold belt rose again in Himalayan, the displacement of the original fault sand shear zones increased, and a series of secondary faults and buried folds formed between the detachment layers. The reservoirs are easy to be destroyed at anticline zones, while the syncline areas are a favorable area for shale gas exploration. The relatively simple deformation for syncline composed of ramp thrusts results in comparable stable internal stress distribution. Related Articles | Metrics