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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 （5508）      PDF （1109KB）（6349）       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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Zinc Isotopes in Environmental Geochemistry: A Review CHENG Wenhan, WU Meng, ZHAO Yanli, ZHAO Junzhe Geological Journal of China Universities    2024, 30 (03): 312-321.   DOI: 10.16108/j.issn1006-7493.2024036 Abstract （1174）      PDF （827KB）（618）       Knowledge map    Save Zinc is one of the essential trace elements for life activities, but in excess, it can cause environmental pollution, ecological toxicity, and harm to human health. Therefore, the study of the environmental geochemical behavior of zinc is the basis for the scientific and rational use of zinc, and it is also a research hotspot in related fields. Zinc has five stable isotopes, and the isotopic composition of zinc varies from different sources. The determination of zinc isotope composition in different  environmental samples provides a new means for studying the environmental geochemistry of zinc. In recent years, with the development of multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS), the study of zinc isotope environmental geochemistry has covered chemical weathering, pollution tracing, paleoclimate reconstruction, and biological processes, and new research fields are constantly expanding. The article provides a detailed overview of zinc isotope analysis methods and their current research status in environmental geochemistry, and looks forward to the future development of zinc isotope environmental geochemistry, in order to promote further development in this field. 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 （3293）      PDF （2398KB）（2807）       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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Discussion on Genetic Classification of Metamorphic Ore Deposits SHEN Qi-han J4    Abstract （1487）      PDF （634KB）（3214）       Knowledge map    Save This paper discusses the definition of the metamorphic ore deposits. On the basis of the preceding study, a new genetic classification scheme is tentatively put forward, in which 5 types and 13 subtypes are discriminated, and representative ore deposits examples are given for each type and subtype. The new classification is shown as follows. (1)Metamorphosed ore deposits, which are subdivided into five subtypes: the metamorphosed banded iron formation (BIF) sedimentary subtype, the metamorphosed BIF volcano–sedimentary subtype, the other metamorphosed sedimentary–volcano–sedimentary formation subtype, the metamorphosed igneous alteration ore deposits subtype and the metamorphosed spilite–keratophyric volcano–eruptive sedimentary ore deposits subtype; (2) Metamorphic ore deposits of regional metamorphism. Three subtypes are included: the metamorphic recrystallization subtype, the components recombination by metamorphic chemical reactions subtype and the metamorphic hydrothermal ore deposits subtype; (3)Metamorphic ore deposits of local metamorphism. Three subtypes are determined: the skarn ore deposits of contact–metasomatism subtype, the local thermal contact–metamorphic subtype and the local dynamo–metamorphic subtype;(4) Metamorphosed sedimentary–volcano–sedimentary ore deposits superimposed and transformed by metamorphic hydrothermal solutions; (5) Ore deposits by migmatism. Two subtypes are included: the migmatitic–metasomatic subtype and the later stage migmatitic–hydrothermal subtype. Related Articles | Metrics Cited: Baidu(3)

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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 （2099）      PDF （6425KB）（1257）       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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Mineralogical Study on Greisenization Zoning and Tin Mineralization in Huashan Granite, Guangxi, South China YU A-Peng, WANG Ru-Cheng, ZHU Jin-Chu, XIE Lei, ZHANG Wen-Lan, CHE Xu-Dong J4    2010, 16 (3): 281-293.   Abstract （2422）      PDF （7693KB）（2384）       Knowledge map    Save Greisen-vein  type  tin deposits are  the most  important mineralization  type  in Huashan granite, Guangxi, South China: The Huashan granite is an oxidized-type granite. In this granite body the element tin predominantly exists as Sn4+  in primary tin- bearing minerals, such as biotite, amphibole,  titanite, rutile,  ilmenite and cassiterite. Based on the comprehensive mineralogical study, we  recognize  that greisenization developed  through  interaction of  the medium-fine-grained biotite granite with a  residual magmatic fliud formed by adequate differentiation and evolution. At the early stage of alteration, the tin in the primary tin-bearing minerals was  leached out by magmatic  fliud, and entered  into  fluid or secondary mineral phases, such as  rutile, muscovite etc. to accomplish  the  first concentration. Then, at  the  later stage of alteration,  the mineralizing  fluid was able  to  redissolve earlier precipitated  tin-bearing minerals, and  tin entered  into mineralizing  fluid  to accomplish  the second concentration. Tin dissolved in fluid combined with ligands, such as F- , Cl -  etc. to form stable complexes and transported. During greisenization, there was an increase  in pH, a decrease  in  temperature and a decrease  in  ligand concentration,  the stabilities of  tin complexes  in  fluid were dropped down, and then the  tin  mineral deposits were formed Reference | 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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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 （1925）      PDF （2414KB）（1657）       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 （2234）      PDF （436KB）（4104）       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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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 （1038）      PDF （3613KB）（1008）       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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Progress in Research on geochemistry of Tungsten MA Dong-sheng J4    Abstract （2716）      PDF （789KB）（4671）       Knowledge map    Save China's tungsten reserves, production, consumption and volume of export all rank first in the world. China has been producing more than 80% of the total production in the world since 2000, and has preponderant influence in the nonferrous metal market of the world. Tungsten as an important strategic resource has found a wide utilization in modern life, industry, oil exploration, military equipments etc. The present paper reviews the progress in research on geochemistry of tungsten in last 20 years, including tungsten distributions in the solar system, in the earth and in the principal units and products from both endogenesis and supergenesis. The geochemical behavior of tungsten in magmas, hydrothermal fluids, supergenesis, and related effects on bionts, environment and health are also discussed. It is pointed out that the geochemistry of tungsten in its effects on environment and health is still a research gap in our country now. Special attention should be paid to this aspect of research. Related Articles | Metrics

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Analyses of Current Main Geochronological Databases and Future Perspectives LI Qiuli, LI Yang, LIU Chunru, LU Kai, QIN Jintang, WANG Fei, WANG Tiantian, WANG Yinzhi, WU Liguang, YANG Chuan, YIN Gongming, LI Xianhua Geological Journal of China Universities    2020, 26 (1): 44-.   DOI: 10.16108/j.issn1006-7493.2019100 Abstract （630）      PDF （8360KB）（1186）       Knowledge map    Save Geochronology, including absolute radio-isotopic dating and relative dating, is an essential subject of Earth sciences. We have seen significant advances in geochronology in the past century as demonstrated by the developments of theoretical systems, techniques, and analytical approaches, which facilitated both the quality and quantity of geochronology data. Within the suitable range of calibration, various dating methods could confirm each other, and the geochronology system becomes more accurate and explicit. For example, high-precision geochronological results and massive micro-analysis data provide time framework for geological events with unprecedented details. They lay the foundation for both quantifying the processes and rates of geological events and underpinning the coupled evolution of the Earth system. As a response to the dramatic increase of geochronological data, many databases for data management and sharing have been developed. The current paper summarizes the features of the existing geochronological databases, as well as advances in both high temporal and spatial resolution geochronology, to explore the opportunities and challenges of developing geochronology in the big data era. Related Articles | Metrics

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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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The Origin of Orbicular Granitoids CAO Yufei, LI Shuting, ZHANG Shaobing, HUANG Fang Geological Journal of China Universities    2024, 30 (06): 635-645.   DOI: 10.16108/j.issn1006-7493.2023067 Abstract （102）      PDF （5289KB）（97）       Knowledge map    Save Granitoids with orbicular structure are very rare because of their unique orbicular structure. They stand as unique objects to study magma processes. When high-temperature magma contacted or mixed with low-temperature magma, due to their difference in viscosity and temperature, high interfacial tension leads the high-temperature magma to form orbicules in low-temperature magma. The temperature of orbicules decrease rapidly and result in high degrees of supercooling. Induced by exsolution of volatiles or other factors, the orbicules begin to crystallize and branched or feathery crystals are formed. The rapid crystallization in orbicules results in rapid change of local melt and the alternating crystallization of different minerals, forming dark and light rings. During this process, the crystallized minerals can exhibit branched or feathery structures. However, it is still unclear how viscosity and temperature control spheroidization, and how minerals crystallize after spheroidization, and how long the crystallization process lasts. These issues are waiting to be studied and revealed. Related Articles | Metrics

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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 （1606）      PDF （2519KB）（1110）       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 of Bio-cementation for Sand Stabilization and Wind Erosion Control HE Jia, WU Min, MENG Hao, QI Yongshuai, GAO Yufeng Geological Journal of China Universities    2021, 27 (6): 687-696.   DOI: 10.16108/j.issn1006-7493.2020072 Abstract （1205）      PDF （1379KB）（1196）       Knowledge map    Save This paper reviews recent research studies on biological soil cementation methods, or bio-cementation, for sand stabilization and wind erosion control. The biological processes adopted for bio-cementation involve microbially- or enzymeinduce carbonate precipitation (MICP or EICP), and the auxiliary use of biopolymers such as xanthan gum can achieve better soil stabilization effects. In the process of soil wind erosion, in addition to the wind itself, the bombardment of the saltating particles carried by the wind is also a key factor of erosion damage. This has been evidenced in the wind erosion tests of bio-cemented soils. The treatment process of soil bio-cementation for wind erosion control is simple and easy. Using urea and calcium salt as treatment materials, and bacteria or urease as catalytic agents, a single-pass spraying treatment on the soil can obtain a good wind resistance effect. In the laboratory wind resistance tests, the combination of wind erosion rate and threshold detachment velocity is a more reasonable evaluation method for wind erosion. In laboratory and field conditions, the surface penetration test can be a simple and quick method to determine the treatment effect and wind erosion resistance. Current field studies indicate that plants can grow in soil with bio-cemented crust, but their growth is restricted under some adverse conditions. Further studies may concentrate on erosion resistance capability under multiple erosion factors, ecological restoration ability in bio-cemented soil, and construction technologies related to the use of bio-cementation, etc. 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 （2792）      PDF （4975KB）（2277）       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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Study on Infrared Spectra and Infrared Radiation Characteristics of Tourmaline LI Wen-wen1, WU Rui-hua1, DONG-Ying2 J4    Abstract （2376）      PDF （570KB）（4347）       Knowledge map    Save This paper studies the infrared spectra (IS) characteristics of different tourmaline species, and the infrared radiation (IR) characteristics after heat treatment on tourmaline species at different temperatures. The results show that the high IR ratio of tourmaline is due to the infrared activity of vibration in its crystal structure. The IR ratio of Fe tourmaline is close to that of Mg tourmaline, and both are higher than that of Li tourmaline. The IR ratio of tourmaline has some relationship with heat treatment temperature: with increasing heat treatment temperature, the IR ratio decreases. When heated to 800℃, the IR ratio reaches a maximum; while heated to higher than 900℃, tourmaline begins to decompose and its infrared radiation ratio drops down. At the room temperature, the largest monochromatic radiation wavelength of tourmaline is between 9μm and 10μm, which matches the wavelength (9.72μm) of the absolute blackbody very well. It demonstrates that tourmaline is a good material for infrared absorption and radiation. Related Articles | Metrics Cited: Baidu(21)

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W-Sn-Nb-Ta-Bearing Granites in the Nanling Range and Their Relationship to Metallogengesis CHEN Jun, LU Jian-Jun, CHEN Wei-Feng, WANG Ru-Cheng, MA Dong-Sheng,ZHU Jin-chu, ZHANG Wen-lan and JI Jun-Feng J4    Abstract （3155）      PDF （3275KB）（4087）       Knowledge map    Save The large-scale mineralizations of W, Sn, Nb and Ta related to granites took place in the Late Jurassic period in Nanling Range, South China. According to the petrological and geochemical features of ore-bearing granites and their relationship to mineralizations, they can be grouped into the following three major types: W-bearing granites, Sn-W-bearing granites and Ta-Nb-bearing granites. The W-bearing granites show low TiO2 and Ba+Sr contents and LREE/HREE ratios,intensive Eu depletion, high Rb and Y abundances and Rb/Sr ratios, and oversaturation in Al. They commonly underwent intensive differentiation and evolution. The Sn-W-bearing granites are characterized by enrichment of TiO2, total REE, HFSEs,Ba+Sr and Rb, higher CaO/(K2O+Na2O) and LREE/HREE ratios, metaluminous-weakly peraluminous feature and lower Rb/Sr ratios, and weaker differentiation and evolation. The Ta-Nb-bearing granites have very low TiO2, Ba+Sr, total REE and HFSEs contents and CaO/(K2O+Na2O) ratios, higher Al2O3/TiO2 and Rb/Sr ratios, higher Rb and Nb contents, and ACNK values. They are highly evolved. Good discrimination can be obtained between these three types of W-Sn-Nb-Ta-bearing granites on plots employing Nb-Y-Ce, (Ba+Sr)-Rb-(Zr+Nb+Ce+Y), LREE/HREE-Rb/Sr and LREE/HREE-(Zr+Nb+Ce+Y) diagrams. These three types of ore-bearing granites have obviously different evolutional trends. Metallogenesis is intimately related to the evolution of the ore-bearing granites. Mineralizations of Sn, W or W-Sn and Nb-Ta or Sn-W-Nb-Ta are closely related to biotite granites, twomica granites or muscovite granites and albite granites respectively. The important deposit types of W, Sn, Nb and Ta and their major features in the Nanling Range are summarized in the paper. The chloritized granite type tin deposit is proposed. This paper indicates that an attention to searching for both the chloritzed granite type tin deposits and greisen-quartz vein type W-Sn deposits in W-Sn-bearing granites in the Nanling Range should be especially paid. Related Articles | Metrics Cited: Baidu(96)

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Petrogenesis and Geologic Implication of the Late Paleoproterozoic A-type Xiaohe Pluton along the Southern Margin of the North China Craton WANG Meixuan, WANG Zhiyi, ZHAO Jingxin, QI Zeqiu, HE Jun, CHEN Fukun Geological Journal of China Universities    2023, 29 (6): 809-830.   DOI: 10.16108/j.issn1006-7493.2022053 Abstract （1195）      PDF （3050KB）（486）       Knowledge map    Save Paleoproterozoic granitoids in the southern margin of the North China Craton are important carriers for studying the crustal evolution in Precambrian. In this study, we report zircon U-Pb ages and whole-rock geochemical compositions of the Xiaohe pluton exposed along the southern margin of the North China Craton in order to discuss its petrogenesis and significance for Precambrian crustal evolution. The Xiaohe pluton is composed of biotite-bearing monzogranite, geochemically, which can be divided into two categories according to its rare earth element characteristics. Type I shows the right dip distribution mode of light rare earth elements enrichment and heavy rare earth elements depletion, which has the characteristics of medium differentiation. Type II has a distribution pattern of rare earth elements with low total rare earth elements, insignificant fractionation of light and heavy rare earth elements, and depletion of middle rare earth elements, which has the characteristics of high differentiation. The zircon U-Pb dating on these two types of granite yielded ~1.80 Ga ages for the emplacement time of the magmas, indicating both of them emplaced in single magmatic period. All the analyzed rocks are rich in silica and alkaline and weakly peraluminous, having high-K alkali-calcareous and calc-alkaline characteristics. They are enriched in Rb, Th, U, K, etc., but depleted in Ba, Sr, P, and Ti. Both types granites have similar Nd-Hf isotopic compositions and their magmas should originate from partial melting of the Late Archean basement rocks along the southern margin of the North China Craton. The magmatism of A-type granite probably represents the tectonicsthermal event closely related to extension, implying a post-collisional/post-orogenic extensional setting along the southern margin of the North China Craton at ca. 1.80 Ga.  Related Articles | Metrics

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Progress in High Precision Analytical Approaches of Silicon Isotope WANG Junlin, WANG Wei, WEI Haizhen Geological Journal of China Universities    2021, 27 (3): 275-288.   DOI: 10.16108/j.issn1006-7493.2021033 Abstract （1047）      PDF （1355KB）（1136）       Knowledge map    Save With the modification of Alkali fusion method for digesting silicates and the development of the multi-collection inductively coupled plasma mass spectrometer (MC-ICP-MS), the silicon isotopic analysis methods have been significantly improved in recent years. The analytical precision of δ 30Si (2SD) is better than ±0.10‰, compared with ±0.15‰-±0.30‰ by gas mass spectrometer (GS-MS) in earlier studies. It enables us to distinguish the minor fractionation of Si isotopes during the high temperature processes; and also avoid using hazardous chemical such as fluoride. For the in situ determination of δ 30Si, the analytical precision of secondary ion mass spectrometry (SIMS) and femtosecond laser ablation (fs LA) also have been modified to be ±0.10‰-±0.22‰. This article reviewed the progress in silicon isotope analysis in the past decades, and discussed the establishment of high precision silicon isotope analysis method under wet plasma condition using MC-ICP-MS. Then we compared the silicon isotopic compositions of standard reference materials in different laboratories, and finally summarized the range of δ 30Si in major geological reservoirs, e.g., BSE, Earth crust and Meteorites. Related Articles | Metrics

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Geochemical Characteristics and Genesis of Dioritic Enclaves in Lisong Granite, NE Guangxi Province YANG Ce, ZHU Jin-chu, ZHANG Pei-hua,XlE Cai-fu J4    Abstract （1614）      PDF （960KB）（1724）       Knowledge map    Save The dioritic enclaves are widely distributed in the Lisong granite. An integrated field and laboratory study on the colours, shapes, textures, structures, compositions, mineralogy and petrology of the enclaves indicates that they are products of rapid crystallization from the silicate melt. The major elements analytical data show a trend characterized by a linear correlation between rock-forming elements. In trace elements, both the dioritic enclaves and hosting granite are enriched in LILEs and HFSEs. Based on the zircon saturation temperature and hornblende geobarometer estimation, the crystallization temperature and pressure of enclaves and hosting granite are very close, in the range of 793 - 824 ℃ and 3.5 - 5. 1 Kb, respectively. The petrological and isotopic features indicate that the Lisong enclaves and hosting granite were basically crystallized at the same time, but with different crust-mantle proportions and different sources. All these integrated data demonstrate that the Lisong enclaves are remnants of magma mingling. Related Articles | Metrics Cited: Baidu(38)

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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 （2589）      PDF （1109KB）（1215）       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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Chinese Text-oriented Geological Semantic Information Annotation and Corpus Construction ZHANG Xueying, ZHANG Chunju, WANG Chen, LIU Wencong, PENG Ye, LU Yanxu Geological Journal of China Universities    2023, 29 (3): 429-438.   DOI: 10.16108/j.issn1006-7493.2023028 Abstract （1127）      PDF （4406KB）（755）       Knowledge map    Save The structured extraction of geological information, semantic analysis, visual expression and the construction of knowledge map in text will provide a strong data foundation and technical support for the deep mining and utilization of geological big data. Whether it is a traditional statistical model or a deep learning model, the semantic analysis of geological information needs the support of tag corpus. In particular, the textual description of geological information has domain characteristics and cannot be achieved by migrating natural language corpora. Therefore, the construction of different levels of geological information annotation corpus has become the key foundation of geological semantic information analysis. Based on the analysis of the characteristics of the geological semantic information description language in Chinese text, according to the spatial and temporal characteristics and attribute description features of the geological entities, various semantic relations of geological entities are clearly expressed, and the geological semantic information is formed, formulating Chinese text labeling system and labeling specifications. The self-developed “interactive geological semantic information labeling tool”solves the shortcomings of traditional manual labeling methods such as high error rates and large workload. Using Chinese mineral resources literature and reports as data sources, a large-scale geological semantic information annotation corpus is constructed, which effectively solves the problem of the lack of large-scale standard data. Related Articles | Metrics

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Dinosaur-related Database Development and Examples of Data-driven Discovery LIANG Qingqing, XING Lida Geological Journal of China Universities    2021, 27 (1): 32-44.   DOI: 10.16108/j.issn1006-7493.2020105 Abstract （956）      PDF （2779KB）（1200）       Knowledge map    Save Dinosaurs are one of high profile symbols in paleontology. They dominated the Mesozoic terrestrial and marine ecosystems and therefore are of great significance to study the Earth evolution. In recent years, along with the rapid increase dinosaurology data and the quick fusion of data science and paleontology, various types of dinosaur-related databases have been constructed worldwide. Those databases serve for different purposes. Some mainly contain introductions for the aim of popular science, some are built for specific research targets and others are comprehensive paleontological database containing dinosaur data. Because none of them is a professional dinosaur database, common defects such as incomplete data coverage and poor data structure, could be found and none has long-term sustainability. With the help of the Deep-time Digital Earth (DDE) big science project, to construct a professional dinosaur database combining the purposes of scientific research and popular science, can promote both the dinosaur evolution study and the public understanding for paleontology. Related Articles | Metrics

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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 （1040）      PDF （1391KB）（2669）       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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A Preliminary Discussion on Large Igneous Provinces and Associated Ore Deposits XIAO Long1, PIRAJNO Franco2, HE Qi1 J4    Abstract （2103）      PDF （773KB）（3824）       Knowledge map    Save Large igneous provinces (LIPs) are grouped into mafic (MLIPs) and silicic (SLIPs), based on their dominant components, mafic or silicic volcanic and intrusive rocks, respectively. The formation of these LIPs requires extremely high heat flow from mantle, which results in extensive melting of mantle, subcontinental lithospheric mantle and lower crust. The typically massive magmatism of LIPs also results in extensive energy and materials exchange thereby causing the formation of a range of important ore systems. MLIPs and SLIPs have different magma sources, compositions, temperatures, pressures, fluids and oxygen fugacities, and experience distinct magmatic evolutionary histories. MLIPs tend to form magmatic Cr-Cu-Ni-PGE sulfide and V-Ti-Fe oxide deposits, some hydrothermal Cu-Pb-Zn-Au-Ag deposits and distal epithermal systems. SLIPs, on the other hand, tend to form metasomatic and/or hydrothermal Cu-Pb-Zn-Au-Ag, W-Sn, U-Th-REE, As-Sb and low-sulfidation epithermal ore systems. Detailed studies of LIPs and associated ore deposits will enable better constrain the metallogenic and ore genesis models, which in turn will help in the discovery of giant ore deposits. Related Articles | Metrics Cited: Baidu(23)

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The Late Cenozoic Basin/Mountain Coupling Mechanics of the Tarim Basin and the Tianshan Mountains LU Hua-fu, WANG Sheng-li, JIA Dong, WANG Liang-shu, LIU Shao-wen J4    Abstract （2219）      PDF （4791KB）（1720）       Knowledge map    Save Based on the data of tectonic geometry and kinematics, oil and gas exploration seismic profiles, seismic sounding reflection, seismic tomography and geothermy, the authors bring forward a conception model of coupling mechanics of the Tarim block＇s and the Junggar block＇s lithosphere mantles collision and delamination under the Tianshan Mountains. Due to India-Asian collision, the north frontier lithosphere mantle of the Tibet Plateau collided with the Tarim lithosphere mantle in V-shape, which pushes the high strength Tarim lithosphere to move northward and to subduct horizontally under the Tianshan Mountains. The subducted lithosphere mantle of the Tarim block collided with the southward subducted lithosphere mantle of the Junggar block and then delaminated in the back peel style under the Tianshan Mountains. While the Tarim block lithosphere mantle was subducting, the Kuqa rejuvenation foreland basin and rejuvenation Tianshan Mountains were formed. The thrust slip in the Kuqa rejuvenation foreland thrust belt accounts for 20% of the Tarim block subduction. This basin and mountain coupling mechanics model may reasonably interpret the features of the basin structures, basin depression, mountain uplift, lithosphere structure and geothermy in this region. Related Articles | Metrics

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Hainan Mantle Plume and the Formation and Evolution of the South China Sea YAN Quan-shu1,2 and SHI Xue-fa1 J4    Abstract （2684）      PDF （771KB）（3878）       Knowledge map    Save Seismic tomographic images obtained from the mantle under the southeast Asia region indicate there may exist a mantle plume beneath and around the Hainan island. A sub-vertical low-velocity column is imaged beneath the Hainan and the South China Sea, and extends from shallow depths to 660-km seismic discontinuity (i.e., the interface between upper mantle and lower mantle), and continuously to a depht of 1900 km. There is a large quantity of Cenozoic alkali basalts distributed in the South China Sea and its adjacent areas which include Leiqiong Peninsula, Hainan Island, Beibuwan Basin, Weizhou Island in Guangxi province and Indochina block. The geochemical data for these basalts show the characteristics of OIB-type basalt and DUPAL-like isotopic anomaly, and imply its deepseated origin. In addition, the average value of Tp (mantle potential temperature) for the South China Sea inferred from olivine-fluid equilibrium, is 1661℃, which is higher than that of MORB and lies between the corresponding values of Hawaii hotspot and Iceland hotspot. Based on evidences mentioned above, combined with numerical model experimental data, it shows that there does exist a mantle plume beneath the Hainan Island and adjacent areas. Until recently, scholars have developed many models about the formation and evolution of the South China Sea, and the debating issue is the geodynamic source. We suggest that the Hainan plume may be a significant geodynamical source for the formation and evolution of the South China Sea. Here the Hainan plume is introduced into our preliminary model about the formation and evolution of the South China Sea. The model is as follows: (1) 50-32 Ma, Integrated effects of collision between thd Indian Ocean plate and Euro-Asian plate resulted in retrogression of Pacific plate, created a extensional tectonic setting, and provided a channel for ascent of the mantle plume; (2) 32-21 Ma. When the head of mantle plume arrived at asthenosphere, it immediately interacted with the spreading center of the South China Sea by lateral material flow, which enhanced spreading spead. During 26-24 Ma, there took place a ridge jump, which adjusted the spreading center from nearby 18。N (i.e., present-day center of NW sub-basin) to nearby 15.5。N (i.e., present-day center of East sub-basin); (3) 21-15.5 Ma. With the mantle plume effect gradually enhancing, the hotspot-spreading center interaction became more and more intensive, and at about 21 Ma, there took place a ridge jump again, and induced the opening of SW sub-basin; (4) 15.5-0 Ma. Due to collision between the Indo-Australian plate and the Sunda continent, the spreading stopped. Subsequently, the earlier formed oceanic crust subducted along Nansha trench and Manila trench. However, the mantle plume still existed up to now. An actual evidence is: since the Pliocene a large amount of alkali basalt erupted in the South China Sea and its adjacent areas. Related Articles | Metrics Cited: Baidu(63)

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Organic matrix-mineral interaction during cell wall  silicification in diatoms SHI Jia-yuan， YAO Qi-zhi， ZHOU Gen-tao J4    2011, 17 (1): 76-85.   Abstract （2385）      PDF （791KB）（4436）       Knowledge map    Save Biosilica, more specifically hydrated amorphous silica, often referred to as opal, is the second most abundant mineral type  formed by organisms, with only  the carbonate minerals exceeding  it  in abundance and distribution. As  the predominant contributor  to biosilica  in  the oceans, diatoms are known  for  the  intricate geometries and spectacular patterns of  their silica- based cell walls. Biochemical studies demonstrate that diatom biosilica is a composite material containing several general organic components in addition to inorganic silica, such as polysaccharides, long-chain polyamines and zwitterionic proteins. Functional studies on these organic components indicate that they play a crucial role in guiding silica precipitation as well as in the formation of species-specific nanopatterns. This article gives an overview of current knowledge on the function of above-mentioned organic and biological molecules  in biosilicification. Moreover, some studies of biomimetic mineralization using model organic additives and in vitro experiments using molecules extracted from organisms are also involved. An insight into the silicification mechanisms in diatoms will link the global cycles for Si and C mechanistically, whereas identification and classification of the components in diatoms may assist us in deeper understanding of material sources of petroleum and the evolutionary development of diatoms. Related Articles | Metrics