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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 （5500）      PDF （1109KB）（6316）       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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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 （1924）      PDF （2414KB）（1646）       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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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 （1012）      PDF （1268KB）（1282）       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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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 （2094）      PDF （6425KB）（1248）       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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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 （2581）      PDF （1109KB）（1203）       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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Genesis Process of the Cretaceous Daqushan Pluton in Zhejiang Province: Crystal-Melt Separation and Magmatic Recharge HE Chen, XIA Yan, XU Xisheng, QIU Jiansheng, XU Hang, ZHANG Zhi, ZHAO Sidi Geological Journal of China Universities    2023, 29 (5): 657-678.   DOI: 10.16108/j.issn1006-7493.2022018 Abstract （2836）      PDF （11167KB）（1124）       Knowledge map    Save The models of trans-crustal magmatic system and crystal mush provide new insights into the study of Cretaceous magmatism in northeast China. The Daqushan pluton is located in the northeast of coastal Zhejiang and Fujian. It is mainly composed of K-feldspar granite with abundant melanocratic microgranular enclaves (MME) and is locally traversed by several mafic-intermediate dikes. A small outcrop of monzonite is exposed near the Chaotoumen. MME have a fine-grained texture with acicular apatites. Zircon U-Pb dating results show that the rock samples in the Daqushan pluton (including the K-feldspar granite, MME, monzonite, and mafic-intermediate dikes) crystallized at ~100 Ma. The K-feldspar granite are highly silicic (SiO2=68.45%-73.82%). While the miarolitic granite (DQS-7) without MME has the higher silica (76.27%), and its whole-rock geochemical and Sr-Nd isotope compositions are similar to those of coeval high silica granites (SiO2>75%) exposed around the Daqushan pluton. Daqushan K-feldspar granite bearing aggregates of plagioclase and K-feldspar exhibit“complementary”trace element geochemical characteristics with Daqushan miarolite and surrounding high silica granites. Further researches show that the Daqushan K-feldspar granite and miarolite were formed by felsic magma which originated from the partial melting of the ancient crustal basement and was recharged by mantle-derived magma. Such felsic magma underwent fractional crystallization and the extraction of high silica melt. Then, the residual silicic cumulate of the crystal mush and high silica melt crystallized and formed the Daqushan K-feldspar granite, miarolite and the surrounding coeval high silica granites. The mafic dikes of Daqushan are enriched in LILEs and depleted in HFSEs and are derived from the partial melting of the enriched mantle metasomatized by subducted dehydration fluids. The results of EPMA analyses indicate that the plagioclase in the K-feldspar granite and MME has a core-mantle-rim texture with low- An in the core (27-36, 25-41) and rim (17-32, 18-26) and relatively high-An in the mantle (28-57, 27-65). Integration of the element geochemical characteristics and Sr-Nd-Hf isotopic results, monzonite and intermediate dikes should be the product of magma mixing of mantle-derived mafic magma and felsic magma, while MME are the product of magma mingling of the two endmembers. The results of the Al-in-hornblende geobarometer show that the crystallization depth of MME is 1.8- 3.0 km, hornblende in monzonite develops core-mantle-rim texture, the crystallization depth of hornblende core and mantle is 17.0-21.2 km, and the depth of hornblende rim is 1.9-4.5 km. Based on the study of the origin and genetic relationships of K-feldspar granite, MME, miarolite, monzonite and mafic-intermediate dikes, and compared with the surrounding coeval high silica granites, this study establishes a model of trans-crustal magmatic systems for Daqushan pluton. The rollback of the subducting paleo-Pacific plate, the back-arc extension in the coastal area and the upwelling of the asthenosphere led to the underplating of the mantle-derived mafic magma, and further induced the partial melting of basement rocks in the lower crust to produce felsic magma. The continuous recharge and heating of mantle-derived magma favor the existence of long-lived melt-bearing regions in magma chambers, promoting magma differentiation and crystal-melt separation and thus forming two magma chambers with depths of 17-21 km and 2-3 km, respectively. K-feldspar granite, high silica granites, monzonite, MME and intermediate-mafic dikes were formed by magma mingling/mixing and crystal-melt separation in two connected magma chambers at different depths. Related Articles | Metrics

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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 （1503）      PDF （7167KB）（1084）       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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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 （1602）      PDF （2519KB）（1082）       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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Marine Redox Fluctuation during the Early Cambrian Age 10: Evidence from U Isotopes QIU Chen, WEI Guangyi, MIN Siyu, CHEN Xi, LING Hongfei Geological Journal of China Universities    2022, 28 (1): 40-50.   DOI: 10.16108/j.issn1006-7493.2020038 Abstract （1860）      PDF （2251KB）（1045）       Knowledge map    Save The marine animal diversity was generally low during late Cambrian and early Ordovician. Biogeochemical studies suggest that it may have been related with fluctuations in oceanic redox conditions, despite still lack of evidence. Well-preserved marine carbonates could record the geochemical characters of ancient seawater, and their uranium isotope compositions (δ238U) can be used to reconstruct the global oceanic redox conditions. In this study we analyzed the uranium isotope compositions of marine carbonates of the basal Cambrian Stage 10 from Wa’ergang section, South China. Our data show that the δ238U profile has three negative excursions with minima of -0.8‰ , -0.55‰ and -0.60‰ , respectively, which indicates three intervals of oceanic anoxia expansion. Modeling results based on the uranium isotope mass balance model suggest that about 22%, 3.5% and 5% of the global sea-floor were covered by anoxic water during these three intervals, respectively. We speculate that the first anoxic interval may have been related with increase in primary productivity due to enhanced weathering input of nutrients, and the latter two may have been induced by upwelling of deep anoxic water during the transgressions. 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）（998）       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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Petrogenesis of Xinmengshan Dacite Porthyry in Changning, Hunan Province: Implications for Relationship of Magmatism and Mineralization ZHAO Zengxia, FENG Zuohai, LIU Lei, XIAO Yang Geological Journal of China Universities    2022, 28 (2): 153-164.   DOI: 10.16108/j.issn1006-7493.2021029 Abstract （1010）      PDF （3021KB）（997）       Knowledge map    Save Based on detailed geological investigation, this paper investigated the whole-rock element geochemistry, zircon U-Pb dating and chlorite mineral chemistry of Xinmegnshan dacite porphyry in Changning City, Hunan Province. With reference to previous research, we discussed petrochemical characteristics, magmatic age, magma sources, as well as relationship with mineralization in Shuikoushan orefield. LA-ICP-MS zircon U-Pb isotopic analyses showed that Xinmegnshan dacite porphyry erupted during the Late Jurassic, with a weighted mean 206Pb/238U age of 152.9±1.2 Ma (MSWD=0.27, 2σ, N=17). Xinmegnshan dacite porphyry was rich in Light Rare Earth Elements (LREEs) and Rb, Th, U, La, Pb, Nd, Zr, Hf, while depleted in Heavy Rare Earth Elements (HREEs) and Nb, Ta, Ba, Sr, P, showing crust-derived affinities, and might be contaminated by mantle material. Chlorite was mainly clinochlore with alteration temperature of 280℃ , which was similar to that of the Cu-Mo mineralization in this orefield. During Late Jurassic, the tectonic extension and thinning of the continental lithosphere in the study area induced partial melting of the crust, and produced granitic magma, which might mix with a small amount of mantle material. The magma then invaded along deep faults and formed Xinmegnshan dacite porphyry. At the late stage of magma crystallization, as Cu-Mo precipitation, the hydrothermal fluid replaced the dacite porphyry continuously and resulted in widespread chloritization. Related Articles | Metrics

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Regional Background and Tectonic Evolution of Dingyuan Sag ZHAN Run, DING Hai, ZHANG Wenyong, SUN Gui, SUI Fengtang, XIN Yongchao Geological Journal of China Universities    2022, 28 (1): 86-95.   DOI: 10.16108/j.issn1006-7493.2020062 Abstract （414）      PDF （6050KB）（966）       Knowledge map    Save Tectonic evolution and its origin of the upper Paleozoic in the Dingyuan Sag are essential for the evaluation of coal resources and exploration targets of unconventional natural gas. Based on the latest geophysical and drilling data, combined with results from previous studies, we discussed the tectonic evolution and its origin in detail via structural analysis and regional comparison. Results show that the upper Paleozoic coal-bearing strata are comparable to the middle segment of the Huainan coalfield, which show an anticline pattern. The Dingyuan Sag has been affected by the strike-slip activities of the Tan-Lu Fault Zone and uplift of the Dabie Orogenic Belt from the Mesozoic to Cenozoic. The tectonic evolution in the Dingyuan Sag can be divided into six main stages, including foreland deformation in the Indosinian (T3), relative uplift in the early-middle Jurassic (J1+2), reformation by strike-slip activities of the Tan-Lu fault zone from the late Jurassic (J3) to early Cretaceous, reformation by extension activity from the early Cretaceous (K1) to Paleogene (E), inversion by compression activity in the late Paleogene, and depression with uniform deposition from the Neogene to Quaternary (N-Q). Related Articles | Metrics

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Development of Teaching Philosophy and Reform of Introduction to Earth Science DAI Jingen, YAN Danping, QIU Liang, CAO Xiuhua Geological Journal of China Universities    2022, 28 (3): 352-356.   DOI: 10.16108/j.issn1006-7493.2021092 Abstract （658）      PDF （1502KB）（958）       Knowledge map    Save “Introduction to Earth Science” is a basic disciplinary course and also the first professional course for junior students major in geology. It undertakes important tasks such as constructing a professional knowledge framework and cultivating interest of students in earth sciences. This paper systematically introduces the development process and achievements of “Introduction to Earth Science” at China University of Geosciences (Beijing), and focuses on the formation process and implementation effects of four teaching concepts such as “teaching the talents”. This paper also emphasizes that high-level teaching team is critical for curriculum construction. After years of teaching practice, a modular teaching system has been proposed, which highlights the key chapters but also has systematic effect. In terms of curriculum design, theoretical and practical lessons have the same amounts of classes, implying the practical characteristics of the course. The teaching method has gradually transitioned from classroom teaching in the past to a combination of classroom teaching, indoor and field geological practice, online learning, and virtual simulation of field practice. The reform and construction of the above-mentioned curriculum system in our university will provide some references for similar courses in related universities. Related Articles | Metrics

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LA-ICP-MS Zircon U-Pb Dating, Geochemical Characteristics and Tectonic Significance of Jundong Granites in Northeastern Guangxi GAO Aiyang, SHI Yu, LIU Xijun, ZHAO Zengxia, LIU Minghui, HUANG Chunwen, Geological Journal of China Universities    2022, 28 (2): 225-239.   DOI: 10.16108/j.issn1006-7493.2021021 Abstract （410）      PDF （5071KB）（932）       Knowledge map    Save The Jundong granitic pluton is located in the southwest of the Qin-Hang belt, with the rock combination of dioritetonalite-granodiorite. In this study, we present LA-ICP-MS zircon U-Pb ages of granitic rocks from the Jundong pluton, the crystallization age of the Jundong rock body is 423-430 Ma, belonging to the Caledonian period. The rocks have lower SiO 2 contents of 55.47-62.95 wt%. One of the samples belongs to the shoshonite series and the others are high-K calc-alkaline series. The A/CNK values are 0.70-1.18, showing as quasi-aluminous or peraluminous rocks. The rocks are enriched in large ion lithophile elements (LILE, e.g., Rb, Ba, Th and U) and relatively depleted in high field strength elements (HFSE, e.g., Nb, Ta, Sr, P and Ti) relative to primitive mantle. The Jundong granitic pluton are mixing products of different original rock sources and formed in the intracontinental collisional orogenic tectonic environment. 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 （1844）      PDF （1237KB）（928）       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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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 （1905）      PDF （2375KB）（853）       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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Practice and Thoughts on Enhanced Blended Learning Based on Knowledge Graph SHI Yukun, XU Shuyi, DONG Shaochun Geological Journal of China Universities    2022, 28 (3): 387-393.   DOI: 10.16108/j.issn1006-7493.2021085 Abstract （1398）      PDF （2385KB）（850）       Knowledge map    Save With the rapid development of the internet and information technology, online and offline blended learning has been widely used. Blended learning is a student-centered strategy that focuses on learners’ abilities of self-regulated learning, collaborative learning and personalized learning and has become a creative learning model for higher education. However, the ability to process, sort, and integrate knowledge that students currently demonstrate under such model is obviously far from sufficient, so is their skill to establish a complete knowledge system. As a result, more guidance from the instructors is urgently needed. The current paper analyzes the advantages and disadvantages of blended learning and introduces the concept of knowledge graph in the field of artificial intelligence as a new element to strengthen the self-regulated learning of students, thereby constructing an enhanced blended learning pedagogy based on knowledge graph. This pedagogy was put into practice in the course of Invertebrate Paleontology at Nanjing University in 2020, which has further demonstrated its potential in improving students’ ability of self-regulated learning. Related Articles | Metrics

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A Sedimentary Record of Environmental and Paleoclimatic Changes in the North Shore of Hangzhou Bay since the Pleistocene LIN Zhongyang, LIU Jian, JIN Xianglong, WU Ming, ZHAO Xudong, PAN Shaojun Geological Journal of China Universities    2022, 28 (1): 129-139.   DOI: 10.16108/j.issn1006-7493.2020035 Abstract （1533）      PDF （3524KB）（836）       Knowledge map    Save The BZK04 borehole (237.80 m deep) is located in the south wing of the Yangtze River Delta and the north bank of Hangzhou Bay. The core contains a relatively complete and continuous sedimentary sequence since the Pleistocene. In this study, the sediment lithology, micropaleontology, sporopollen assemblage, particle size content, paleomagnetism and OSL dating of the core were analyzed comprehensively, the characteristics of depositional environment evolution and paleoclimatology changes since the Pleistocene in the research area were discussed, and the framework of quaternary multiple stratigraphic divisions and correlatiosn was established. The results show that from bottom to top, the BZK04 core can be divided into carbonaceous mudstone （Ech） of the Changhe Formation, and the Jiaxing Formation（N-Qp1j）, Qiangang Formation（ Qp2q）, Dongpu Formation（ Qp3d）, Ningbo Formation （Qp3n） and Zhenhai Formation （Qhzh） since the early Pleistocene epoch; Foraminifera of 17 species in 11 genera were identified , including 16 benthonic foraminifera and 1 planktonic foraminifera; The ostracod of 8 species in 8 genera was identified ; Pollen analysis reveals that there were 37 types of pollen, including 18 woody plant pollen, 11 herbaceous pollen, and 8 fern spore; The content of woody plants was the highest in the palynological assemblage (85.1%), followed by fern spores (8.7%) and herb pollen (6.3%). According to the comprehensive analysis of the sedimentary environment of borehole by lithologic stratification features, sedimentary facies, sporopollen, foraminifera and ostracodes, and grain size distribution frequency curve, the depositional environmental record is characterized by 18 pollen assemblages and 7 paleoclimatic cyclic changes, among which the early Pleistocene is dominated by fluvial and lacustrine facies deposits, indicating two paleoclimatic cycles from the third warm period to the fourth cold period; The middle Pleistocene was dominated by fluvial facies, lacustrine facies, and fluvial and lacustrine facies, revealing two paleoclimatic cycles from the fifth warm period to the sixth cold period; The late Pleistocene is dominated by the tidal-flat facies, estuarine facies and neritic facies, corresponding to two paleoclimatic cycles from the seventh warm period to the eighth cold period; In the Holocene, there were tidal-flat facies, fluvial and lacustrine facies, corresponding to the Atlantic and boreal periods. This study provides an important basis for further understanding the changes in quaternary sedimentary environment, the stratigraphic divisions and the paleoclimate evolution since the Pleistocene in the southern side of the Yangtze River Delta. 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 （233）      PDF （711KB）（819）       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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LA-ICP-MS Zircon U-Pb Dating and Hf Isotopic Composition of Dacite in Hezhou, Northeastern Guangxi WANG Yongqiang, SHI Yu, LI Xiang, LIU Xijun, TANG Yuanlan, SUN Yirong Geological Journal of China Universities    2022, 28 (2): 141-152.   DOI: 10.16108/j.issn1006-7493.2021027 Abstract （798）      PDF （3932KB）（788）       Knowledge map    Save The study area is located at the junction of Hunan and Guangxi in the western part of Nanling metallogenic belt, where Mesozoic magmatic activity is frequent and the diagenesis and mineralization are remarkable, especially during Yanshanian. In order to determine the formation age of kongzimiao dacite in Kaishan Town, Hezhou, northeastern Guangxi, and to discuss its source property, LA-ICP-MS zircon U-Pb dating and Lu-Hf isotope are obtained. zircon U-Pb age of 157.1±0.9 Ma displayed the formation age of the dacite. Zircons grains have a wide range of isotopic composition (εHf(t) values rang from -5.68 to -0.97), with corresponding two-stage Hf isotope model age (TDM2) varying from 1.26~1.54 Ga, suggesting that the protolith was predominantly derived from the crystalline basement crust in Mesoproterozoic, and may be accompanied by a small amount of mantle-derived materials. Combined with the previous studies on the Yanshanian diagenesis and mineralization in South China, it is considered that the dacite in the study area and the early Yanshanian rocks and deposits in Northeast Guangxi are the products of the first large-scale magmatic activity in the Yanshanian in South China, and the formation of dacite may be related to the intraplate extension thinning of the Yanshanian lithosphere in South China. Related Articles | Metrics

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Ce-in-zircon Oxybarometer and the Redox State of the Early Earth XIAO Luyi, YANG Xiaozhi Geological Journal of China Universities    2022, 28 (4): 484-492.   DOI: 10.16108/j.issn1006-7493.2020114 Abstract （2157）      PDF （1097KB）（764）       Knowledge map    Save Oxygen fugacity ( f O 2), a quantitative factor in rendering the redox state of a given system, is a key thermodynamic parameter in Earth sciences. The oxygen fugacity of the early Earth and its variation with time, which is a prime goal of Earth sciences, plays important roles in understanding the origin and evolution of the atmosphere, hydrosphere, biosphere and even the whole Earth. Zircon provides the oldest samples yet found on the planet, and is almost the only survivor of the Hadean period. Studies in recent years have demonstrated that the Ce content of zircon is able to record the prevailing f O 2 of its parent magma, leading to the so-called Ce-in-zircon oxybarometer. This provides a unique probe into the redox state of the early Earth. We provide a brief introduction of this technique, and then outline the recent advances on the redox state of the early crust and mantle, followed by a discussion on the f O2 evolution of the early atmosphere, crust and upper mantle and the coupling relation of  f O 2 between them. Related Articles | Metrics

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Construction and Application of Lithofacies Paleogeography Knowledge Graphs ZHANG Jiajia, ZHANG Lei, ZHONG Hanting, WANG Han, CHEN Anqing, LI Fengjie, REN Qiang, ZHENG Dongyu, ZHAO Hongyi, HOU Mingcai Geological Journal of China Universities    2023, 29 (3): 345-358.   DOI: 10.16108/j.issn1006-7493.2023027 Abstract （1137）      PDF （2348KB）（763）       Knowledge map    Save Big data has brought new ideas and challenges to lithofacies paleogeography research. However, due to the problems of complex data types, rich semantic relationships and unclear sharing mechanisms, it is difficult to conduct in-depth data mining, analysis, and effective utilization of lithofacies paleogeographic data, which makes making many advantages of big data not fully exploited in this field. The powerful semantic processing and open interconnection capabilities of knowledge graphs, make it plays an important role in solving the problems of big data text analysis and image understanding, which and haves broad application prospects. This paper summarizes the research background of lithofacies paleogeography knowledge graphs from the perspective of construction and application; by systematically investigates investigating the construction ideas, technologies and processes of lithofacies paleogeography knowledge graphs., and The paper also lists outlines the relevant applications of knowledge graphs in lithofacies paleogeography; and points out the main problems of lithofacies paleogeography knowledge graphs, prospects for future research directions. 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 （1185）      PDF （7113KB）（762）       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

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Investigation of Oedometer Test and Mechanism of Soft Soil Improved Using Microbial Composite Material LIU Qing, LIN Jun, XIE Jiamin, QIN Pengfei Geological Journal of China Universities    2023, 29 (3): 487-496.   DOI: 10.16108/j.issn1006-7493.2021114 Abstract （1245）      PDF （2723KB）（760）       Knowledge map    Save Microbial induced carbonate precipitation (MICP), as an eco-friendly technology, has been used to improve the mechanical properties of soil. However, it is difficult to apply the MICP to soft soil foundation treatment due to the poor engineering properties. The MICP-sand drain combined with vacuum drainage and MICP-biochar were introduced to the soft soil, and the amount of sand drain and biochar mixing ratio were studied using oedometer test. The microstructures were investigated to reveal the precipitation patterns of calcium carbonate by using SEM and XRD tests. The results showed that porosity ratio decreased with the increase of in number of sand drain and biochar mixing ratio. The coefficient of compressibility and modulus of compression could be improved when the contents of biochar were in a certain range (about 8%). The analysis of calcium carbonate content showed reveal that the amount of calcium carbonate decreased gradually with the increase of in depth, which presented presents non-uniformity of calcium carbonate distribution. Additionally, a large amount of calcium carbonate was observed in the two methods, which were deposited on the contact of soil particles. The crystal type of calcium carbonate was determined as vaterite. Related Articles | Metrics

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Hydrocarbon Generation Potential of Pre-Paleogene Source Rocks in the Jiyang Depression#br# NIU Zicheng, WANG Yongshi, WANG Xuejun, ZHANG Xuejun, WANG Xiuhong, HAN Dongmei, LIU Xuan, WANG Ru, WANG Juan Geological Journal of China Universities    2022, 28 (1): 73-85.   DOI: 10.16108/j.issn1006-7493.2020068 Abstract （563）      PDF （3979KB）（758）       Knowledge map    Save Multiple sets of pre-Paleogene strata with relatively low exploration levels have developed in the Jiyang Depression. The Lower Paleozoic Cambrian-Ordovician, Upper Paleozoic Carboniferous-Permian and Mesozoic all host source rocks and thus can theoretically generate oil and gas for accumulation in the study area. Different tectonic and sedimentary backgrounds lead to different geochemical characteristics among different sets of source rocks. This study comprehensively analyzes  data of geology, source rock pyrolysis and TOC, vitrinite reflectance, whole rock microscopic composition, and gas chromatography-mass spectrometry of saturated and aromatic hydrocarbons. The distribution, geochemistry and resource potential of the pre-Paleogene source rocks in the Jiyang Depression were determined. The Lower Paleozoic marine carbonate source rocks have limited distribution and low abundance of organic matter, but have organic matter types favourable for certain hydrocarbon generation capacity. The widely distributed Upper Paleozoic coaly source rocks, with high abundance of organic matter and relatively poor organic matter types, are dominated by gas generation. As a result of complex tectonic evolution, this set of source rock is characterized by secondary hydrocarbon generation. The Mesozoic has developed two sets of source rocks (i.e., coaly source rocks and lacustrine mudstones) with medium organic matter types. Medium- to good-quality source rocks are developed locally with varying maturity spatially. Overall, among the thr ee sets of pre -Paleogene source rocks in the Jiyang Depression, the Upper Paleozoic coal-measure source rocks have the best quality, followed by the Mesozoic, and the Lower Paleozoic is relatively poor. 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 （992）      PDF （4598KB）（747）       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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Petrogenesis of the Jurassic Representative Volcanic Rocks in Eastern Guangdong: Response to the Early Stage of the Paleo-Pacific Subduction YUE Xiaohan, LIU Lei, ZHANG Zhiguo, ZHAO Zengxia, SUN Jie, ZHAO Yang Geological Journal of China Universities    2022, 28 (2): 199-210.   DOI: 10.16108/j.issn1006-7493.2021022 Abstract （909）      PDF （2636KB）（746）       Knowledge map    Save It is widely accepted that the widespread Cretaceous volcanic rocks in SE China were formed at the late stage of the paleo-Pacific subduction. On the contrary, the geological response of the early stage of the subduction remains unclear. This study focuses on the representative Jurassic volcanic sections in eastern Guangdong, which are the most widespread in SE China. Zircon U-Pb dating results reveal that the Jurassic volcanic rocks were formed intermittently at 192-183 Ma (Songling Fm.), 177- 163 Ma (Jilingwan Fm.) and 162-156 Ma (Gaojiping Gp.). Thus, a younging trend along eastern Guangdong to eastern Fujian to southeastern Zhejiang could be identified for the entire Late Mesozoic volcanic rocks in SE China. Zircon Lu-Hf isotopic analyses show that the Jurassic volcanic rocks were mainly derived by remelting of the Paleoproterozoic crustal basement, with decreasing involvement of juvenile components in their origin over time from Early to Late Jurassic. The petrogenesis of the Jurassic volcanic rocks in eastern Guangdong suggests decreasing crustal extension, corresponding to the forward subduction of the paleo-Pacific slab. Thus, the Jurassic volcanic rocks in eastern Guangdong record the early stage of the paleo-Pacific subduction, and further suggest that the subduction started at around Early Jurassic. 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 （1122）      PDF （4406KB）（742）       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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Research on the Joint Extraction Method of Entity Relations in Geological Domain QIU Qinjun, WANG Bin, XU Dexin, MA Kai, XIE Zhong, PAN Shengyong, TAO Liufeng Geological Journal of China Universities    2023, 29 (3): 419-428.   DOI: 10.16108/j.issn1006-7493.2023026 Abstract （1100）      PDF （1153KB）（740）       Knowledge map    Save Entity relationship extraction for the geological domain is the basis for building a geological knowledge graph, and is very important for text information extraction and knowledge base construction in the geological domain. In view of the complexity of entity relations in geological domain and the lack of a manually annotated corpus, a joint extraction model for entity relations in geological domain is proposed, focusing on the recognition of complex overlapping relations in multiple geological texts and avoiding cascading errors caused by entity recognition errors in the traditional pipeline model. In this paper, a high-quality corpus of entity relations in the geological domain is constructed, and a pre-trained language model based on BERT (Bidirectional Encoder Representations from Transformers) and BiGRU (Bidirectional Gated Recurrent Units) is proposed. Recurrent Units and Conditional Random Field (CRF) sequence annotation models to achieve joint extraction of entity relations. Experiments were conducted on the constructed dataset, and the results showed that the F1 value of the joint extraction model proposed in this paper reached 0.671 for entity relationship extraction, which verified the effectiveness of the model in this paper for geological entity relationship extraction. Related Articles | Metrics

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Comparative Analysis and Enlightenment of Geoscience Knowledge Graphs: A Perspective of Construction Methods and Contents ZHU Yunqiang, SUN Kai, LI Weirong, WANG Shu, SONG Jia, CHENG Quanying, YANG Jie, MU Xinglin, GENG Wenguang, DAI Xiaoliang Geological Journal of China Universities    2023, 29 (3): 382-394.   DOI: 10.16108/j.issn1006-7493.2021111 Abstract （1369）      PDF （1366KB）（734）       Knowledge map    Save Geoscience knowledge graphs (GKGs) formally represent geoscience knowledge in a way of directed graph and have strong capabilities in knowledge representation, openness and interconnectivity, and reasoning and prediction. GKGs have been one of the important infrastructures for the development of combining geoscience and artificial intelligence, thereby becoming one of the important research focuses in geoscience. Therefore, many international scientific organizations or groups have successively carried out studies in this domain, and constructed some representative GKGs. However, there is a lack of an in-depth study and analysis of these existing GKGs. To this end, this paper makes a systematic comparative analysis on their general information, construction methods, and main contents. On this basis, some enlightenments about future research of GKGs are discussed. In terms of the construction method, a unified representation framework for GKGs should be built, the source of geoscience knowledge should be enhanced by conflating multi-source and multimodal data, and methods for the representation and computation of geoscience knowledge should be studied. Regarding the contents of GKGs, complex spatiotemporal characteristics, relations, and reasoning rules should be considered. From the perspective of application, methods for assessing quality and making correction for geoscience knowledge should be developed, and application effects of GKGs should be improved. Related Articles | Metrics