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Progress of Methods for Assessing CO2 Mineralization Storage Potential in Basalt GAO Zhihao, XIA Changyou, LIAO Songlin, YU Xiaojie, LIU Muxin, LI Pengchun, LIANG Xi, DAI Qing, HUANG Xinwo Geological Journal of China Universities    2023, 29 (1): 66-75.   DOI: 10.16108/j.issn1006-7493.2022099 Abstract （2960）      PDF（pc） （1109KB）（2718）       Knowledge map    Save CO2 geological storage is an important technology to reduce CO2 emissions, which can safely store CO2 in geological formations for millions of years. Conventional CO2 storage reservoirs include deep saline aquifers and depleted oil and gas reservoirs. Basalt is a new type of CO2 storage reservoir that has been attracting attention in recent years. CO2 storage in basalt would increase the technical method and potential of CO2 geological storage. Storage potential assessment is one of the fundamental works of CO2 geological storage study. This paper systematically examines the current methods for assessing the storage potential of CO2 in basaltic rocks, and analyzes the principles and application scenarios of various methods. Then, the study takes the basalt of Icelandic Active Rift zone as an example to compare each of the methods. The study suggests that the current CO2 mineralization storage potential assessment methods generally include three categories: ① Unit rock storage potential assessment method, which evaluates carbon sequestration potential based on the reaction volume or area of rocks; ② Mineral replacement storage potential assessment method: based on the volume of minerals that can react with CO2 in basalts. ③Pore filling storage potential assessment method, which evaluates the proportion of secondary minerals that can fill reservoirs’ pore space after CO2 mineralization. The authors note that the first method requires special experimental analysis, making it more challenging, the second method is more appropriat for basalts with high porosity and low reactive mineral content, while the third method is more suitable for basqlts with low porosity and high reactive mineral content. Related Articles | Metrics | Comments（0）

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Sensitivity Analysis of Rock Stress Wave Propagation and Attenuation Characteristics Based on MatDEM FAN Guansheng, HUANG Yehuan, LIU Chun, LE Tiancheng Geological Journal of China Universities    2023, 29 (3): 479-486.   DOI: 10.16108/j.issn1006-7493.2021102 Abstract （1076）      PDF（pc） （6972KB）（2361）       Knowledge map    Save The study of stress waves is a key issue in the dynamic action of rocks. Based on the discrete element method, this paper carries out numerical simulation tests on rock samples to explore the influence factors and laws of stress wave propagation and attenuation. The analysis focuses on the influence of the element radius, damping coefficient, incident wave frequency and amplitude on the stress wave propagation of the rock numerical sample, compares and analyzes the real test results. The research results show that the discrete element method can effectively simulate the dynamic process, and the variation law of the stress wave propagation in the numerical rock sample is consistent with previous studies. The increase in the radius of the rock sample unit will increase the unevenness of the rock sample and increase the scattering attenuation; the larger the damping coefficient, the greater the attenuation of the amplitude at the same distance; the frequency of the incident wave in the rock sample decreases, the wave propagation trend develops from logarithmic attenuation to linear attenuation; the greater the amplitude of the loading wave, the greater the attenuation of the stress wave due to scattering, and the attenuation rate at the same propagation distance remains constant.  Related Articles | Metrics | Comments（0）

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Status and Advances of Research on Caprock Sealing Properties of CO2 Geological Storage CHEN Bowen, WANG Rui, LI Qi, ZHOU Yinbang, TAN Yongsheng, DAI Quanqi, ZHANG Yao Geological Journal of China Universities    2023, 29 (1): 85-99.   DOI: 10.16108/j.issn1006-7493.2023010 Abstract （2455）      PDF（pc） （6425KB）（2113）       Knowledge map    Save CO2 Geological storage is one of the key technologies to address global climate changes and reduce greenhouse gas emissions. Large-scale CO2 injection into the formation is prone to inducing CO2 leakage problem. In particular, the leakage problem of CO2 through caprock includes capillary leakage, hydraulic fracture and leakage along pre-existing faults crossing caprock. Therefore, evaluation of caprock seal is crucial for prediction of long-term safety and stability of CO2 geological storage. This paper provides an overview of the current status of research on sealing mechanisms, influencing factors, and damage modes affecting caprock seal of CO2 geological storage. It is concluded that caprock seal mechanisms include capillary seal, hydraulic seal, and overpressure seal. The main influencing factors of caprock seal characteristics include caprock lithology, mudrock-sand ratio, caprock mechanical properties, and sequestration pressure. Then, the damage modes of caprock seal during CO2 injection are illustrated, and some insight into the shortcoming of caprock seal is provided. Related Articles | Metrics | Comments（0）

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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 （1877）      PDF（pc） （2519KB）（2087）       Knowledge map    Save In order to investigate the physical and mechanical characteristics of coral reefs with different depth in the South China Sea, scanning electron microscopy (SEM) and X-ray tomography (CT) technology are used to characterize the micro morphology and internal pore structure characteristics of shallow and deep reef limestone. Quantitative relationships between P-wave velocity and porosity as well as density were established. Uniaxial compression tests on dry and saturated reef limestone were also carried out. Results show that shallow reef limestone is porous with excellent pore connectivity, and the main mineral composition is aragonite, which belongs to the biological sedimentary rock. While deep reef limestone is dense with poor pore connectivity, and the main mineral composition is calcite, belonging to the metamorphic rock. The porosity of deep reef limestone is about 1/10, with an average peak compressive strength of about 4.8 times and an average elastic modulus of about 4.5 times that of shallow reef limestone. Reef limestone belongs to soft or extremely soft rock, characterized by brittle destruction property. The typical damage pattern is multiple rupture surface destruction along the primary pore, growing line of corals and weak bond surface, with high  residual strength. The hydrogenic effect of reef limestone is significant, and the water rationality of deep reef limestone is stronger than shallow reef limestone. The significant difference of physical and mechanical performances in shallow and deep reef limestone are mainly due to the variety in mineral components, pore structure and lithology caused by the varying degree of rock cementation with different depths. Related Articles | Metrics | Comments（0）

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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 （1364）      PDF（pc） （2348KB）（2080）       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 | Comments（0）

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One-stop Sharing and Service System for Geoscience Knowledge Graph ZHU Yunqiang, DAI Xiaoliang, YANG Jie, WANG Shu, SUN Kai, QIU Qinjun, LI Weirong, QI Yanmin, HU Lei, LYU Hairong, WANG Xinbing, ZHOU Chenghu Geological Journal of China Universities    2023, 29 (3): 325-336.   DOI: 10.16108/j.issn1006-7493.2023029 Abstract （1764）      PDF（pc） （7167KB）（1965）       Knowledge map    Save As the most effective way of knowledge organization and service at present, knowledge graph has become the cornerstone of artificial intelligence and has been widely used in semantic search, machine translation, information recommendation and so on. In the era of big data, there is an urgent need of Geoscience knowledge graphs for integrating, mining and analysis of scattered, multi-source and heterogeneous Geo-data and its unknown knowledge intelligent discovery. To promote the construction and application of Geoscience knowledge graphs, the Deep-time Digital Earth (DDE) International Big Science Program has taken knowledge graph as its one of the core research contents since its launch in 2019. After more than three years of construction, DDE has built a large number of Geoscience knowledge graphs, and it strong needs one-stop sharing and service system of these knowledge graphs. Firstly, this paper introduces the content framework, composition as well as characteristics of the DDE knowledge graphs. On this basis, the design of the one-stop sharing and service system for the Geoscience knowledge graph is designed that include the design of the system functional and technical architecture. Finally, the development and operation environment & tools, and key technologies of the system are discussed in detail. The practice has proved that the system can effectively realize the one-stop sharing and open access of DDE knowledge graphs. Meanwhile, it sets an example for other fields or domains’ knowledge graph integrating and sharing systems. Related Articles | Metrics | Comments（0）

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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 （2032）      PDF（pc） （2375KB）（1907）       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 SiO2 contents, total alkalis contents and ACNK values ( ≥ 1.1), low FeOt+MgO+TiO2 contents and P2O5 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 SiO2 contents and Rb/Sr ratios, but lower FeOt+MgO+TiO2 contents, P2O5 contents, Zr/Hf ratios, and Fe2+/(Fe2++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 | Comments（0）

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Tectonic Attributes and Continental Affinities of the Precambrian Blocks in the Southwestern Central Asian Orogenic Belt WANG Bo, SUN Zhaochen, SONG Fang, NI Xinghua, CAO Tingting, LIU Jiashuo Geological Journal of China Universities    2023, 29 (3): 439-454.   DOI: 10.16108/j.issn1006-7493.2021073 Abstract （1284）      PDF（pc） （2285KB）（1824）       Knowledge map    Save Numerous ribbon-like micro-plates develop in the southwestern part of the Central Asian Orogenic Belt (CAOB), they are important constituents of the Kazakhstan microcontinent, understanding of their tectonic attributes, continental affinities and crustal evolution is essential for the reconstruction of the accretionary history and geodynamic processes of the CAOB. The controversies remain for a long time about the basement compositions, tectonic settings and affinities of the micro-plates. This paper compiles recently published geological and isotopic chronological data, and summarizes rock assemblages, ages and tectonic settings of the Precambrian basement, and further analyzes the tectonic attributes of the micro-plates and their possible affinities with the surrounding continental plates. The available data indicate that the Meso- and Paleoproterozoic crystalline basement only develop in a few micro-plates (such as Chinese Central Tianshan, Kyrgyz Middle Tianshan, Issyk-Kul, Zheltau and Kokchetav), but are not recorded in the other micro-plates (such as South Yili, North Yili-Aktau, Chu-Ili, Karatau, Baikonur, Erementau and Ulutau) in the SW CAOB. However, similar Neoproterozoic metamorphic and magmatic rocks were documented in all these micro- plates and form the comparable metamorphic and crystalline basement. A comprehensive comparison and analysis allow us to conclude that these micro-plates may have different origins, but they experienced similar tectonic and magmatic evolution since Neoproterozoic, and underwent comparable paleogeographic environment, suggesting Early Neoproterozoic convergent orogenesis, Late Neoproterozoic continental rifting and formation of passive continental margins during the opening of the Paleo-Asian Ocean. Related Articles | Metrics | Comments（0）

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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 （2122）      PDF（pc） （1237KB）（1753）       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 | Comments（0）

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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 （1613）      PDF（pc） （1366KB）（1592）       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 | Comments（0）

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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 （1368）      PDF（pc） （827KB）（1479）       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 | Comments（0）

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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 （1219）      PDF（pc） （3613KB）（1439）       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 | Comments（0）

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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 （1379）      PDF（pc） （7113KB）（1433）       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 | Comments（0）

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Evolution of Oceanic Redox State during Early Ordovician Tremadocian Age Traced by Uranium Isotopes MIN Siyu, QIU Chen, LUAN Xiaocong, WU Rongchang, SHAO Qingfeng, CHEN Xi, LING Hongfei Geological Journal of China Universities    2023, 29 (2): 147-160.   DOI: 10.16108/j.issn1006-7493.2021052 Abstract （2006）      PDF（pc） （1506KB）（1423）       Knowledge map    Save The oceanic redox state is one of the important environmental factors affecting evolution of animals in the ancient ocean. The Ordovician Tremadocian Stage was the‘eve’of the Great Ordovician Biodiversification Event (GOBE), during which the biodiversity was gradually increasing. However, there has been lack of researches on evolution of ocean redox state for this key interval. Studies have proved that the U isotope compositions recorded in well-preserved carbonates can effectively trace the redox state of the global ocean redox state. In this study, we conduct systematical analyses of carbon and oxygen isotope compositions and uranium isotope compositions of carbonate samples from the Xiangshuidong section in Songzi, Hubei Province. A significant positive carbon isotope excursion event—TSICE is identified at the base of the middle Tremadocian stage. The average value of  δ238U increased from -0.64‰ ±0.12‰ to -0.26‰ ±0.15‰ across the TSICE, which indicates that the redox state of the global ocean changed from significantly anoxic (mass balance model results indicating >2.56% of the seafloor covered by anoxic seawater) to much more oxygenated before and after the TSICE. This process of environmental change is consistent with the process of increase in metazoan proportion relative to microorganism proportion in reef composition. The positive drift of carbon and uranium isotope compositions may have been related to the regression and sea-surface temperature decrease, respectively, which may have been conducive to oceanic oxidation. Related Articles | Metrics | Comments（0）

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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 （1344）      PDF（pc） （1153KB）（1331）       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 | Comments（0）

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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 （340）      PDF（pc） （711KB）（1300）       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 | Comments（0）

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Origin and Genetic Mechanism of the Early Cretaceous Metabasite from the Ramba Area, Tethyan Himalaya YU Youzhi, LIU Zhichao Geological Journal of China Universities    2023, 29 (4): 527-542.   DOI: 10.16108/j.issn1006-7493.2022007 Abstract （1654）      PDF（pc） （4128KB）（1290）       Knowledge map    Save A large number of Early Cretaceous mafic rocks are widely exposed in the Tethyan Himalaya, southern Tibet, China. These rocks provide an important record of the tectonic-magmatic evolution of the north margin of the Indian continent before the Cenozoic Indian-Eurasian collision. Their genesis is critical for reconstructing the evolution history of the Indian passive margin. This paper presents systematical petrographic and geochemical data of the Early Cretaceous metabasites from the Ramba area, eastern Tethyan Himalaya. The Ramba metabasites include amphibolitie-amphibolitic gneisses, which occurred as dikes and lenses in the low-medium grade metasedimentary rocks of the Ramba dome. These Ramba metabasites display tholeiitic affinity and low contents of SiO2 (44.78-47.42 wt%), relatively high contents of MgO (7.31-9.60 wt%) and FeOt (9.68-15.87 wt%) with variable TiO2 contents (0.73-2.16 wt%) and medium to high Mg# values (46.4-63.9). The radiogenic Nd isotopic compositions of the Ramba metabasites (εNd(t) values range from 5.7 to 6.5) are comparable with that of the Indian Oceanic MORB. However, the REEs distribution patterns of the Ramba metabasites are similar to that of the E-MORB, indicating involvement of enriched components in their origin. It is worth noting that the Ramba metabasites do not show depletion in high-field-strength elements (HFSE), and their Nb/U ratios are similar to that of the mantle-derived rocks. Therefore, it can be inferred that the continental crust contamination is not significant in the formation of Ramba metabasites and their enrichment components should be mainly attributed to an enriched mantle source. Consequently, it is speculated that the Ramba metabasites were products of the interaction between magma derived from a depleted asthenospheric mantle and an enriched continental lithospheric mantle. They were generated during the early stage of the breakup of eastern Gondwana (~140 Ma) and were originated from the asthenosphere upwelling that was triggered by early activity of the Kerguelen mantle plume. Related Articles | Metrics | Comments（0）

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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 （1343）      PDF（pc） （4406KB）（1284）       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 | Comments（0）

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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 （1270）      PDF（pc） （4598KB）（1282）       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 | Comments（0）

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Discovery of Volcanic Clay-type Lithium Deposit in Region of Volcanic Rocks Along the Southeastern Coast of China SHAO Xiaoyang, DENG Fei, ZHANG Zhongjin, WANG Rucheng, LU Xiancai, CHE Xudong Geological Journal of China Universities    2024, 30 (04): 409-417.   DOI: 10.16108/j.issn1006-7493.2024031 Abstract （1427）      PDF（pc） （5089KB）（1280）       Knowledge map    Save We report the lithium enrichment in the late Cretaceous Yetang Formation, located in the Shirenbei Basin, northeast of Guangdong Province. The Li2O content is greater than 0.2%, and can be a target for extracting lithium. Comprehensive crosssections of the Shirenbei Basin, geochemical analyses and lithofacies interpretation suggest that the lithium-enriched layers occur in shale, mudstone and siltstone, located in Middle-Upper Yetang Formation; lithium is mainly stored in clay minerals, whose formation is closely related to volcanic activities. It was initially interpreted as a volcanic-type lithium-rich clay deposit. The basin structure provides the environment for sedimentation and concentration of lithium. The layers containing enriched lithium are approximately 226 meters thick in total, and are in great potential for extracting lithium deposit. This discovery provides fclues on investigating large-scale lithium-rich clay deposits related to volcanic activities along the southeast coast of China.  Related Articles | Metrics | Comments（0）

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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 （1463）      PDF（pc） （2723KB）（1272）       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 | Comments（0）

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Advances on the Analogue Modeling of the Emplacement of Granitic Magma LI Yingying, WANG Bo, CAO Tingting Geological Journal of China Universities    2023, 29 (4): 543-558.   DOI: 10.16108/j.issn1006-7493.2022055 Abstract （1496）      PDF（pc） （7635KB）（1271）       Knowledge map    Save Regional tectonics not only facilitate the ascent and emplacement of the granitic intrusions but also control the final shapes of the intrusions. Analogue modeling is a critical method to study the magma emplacement. This paper reviewed the experimental set-up, materials and scaling used in previous analogue models related to magma emplacement, and summarized the influence of various parameters on the geometry of the intrusions in various tectonic settings. We suggested that: (1) the intrusion geometry is controlled by the characteristics of the country rocks in pre-kinematic static settings during tectonic quiescent stage. (2) In syn-kinematic settings during tectonic active stage, the intrusion geometry and deformation patterns of plutons are influenced by several parameters, including the thickness and rheological layering of the country rocks, velocity and total distance of displacement, velocity and total volume of magma injection, position of the injection inlet (magma channel), relative timing of tectonic activity and magma emplacement. Deformation can in turn control the shape of intrusions. (3) The parameters, such as displacement velocity and injection velocity in different settings, have similar impact on the intrusion geometry. In addition, some limitations of analogue modeling method are also discussed. The CT technique and numerical modeling methods are suggested to be profitable supplementation of analogue modeling for the study in magma emplacement.  Related Articles | Metrics | Comments（0）

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NaOH Alkaline Fusion Method for B Isotope Analysis of Silicates LI Zhenghui, CAI Yue, WEI Haizhen, LI Ye, ZHANG Weiwei, LI Baichan Geological Journal of China Universities    2024, 30 (02): 133-141.   DOI: 10.16108/j.issn1006-7493.2023004 Abstract （1117）      PDF（pc） （924KB）（1270）       Knowledge map    Save Boron(B) isotope analysis is an important tool in the research of earth and planetary science. However, challenges still exist for precise and accurate measurements of boron isotope ratios of silicate material due to the challenges in sample digestion. Alkaline fusion is a suitable sample dissolution method for boron isotope analysis in silicates. At present, alkaline fusion  methods require expensive platinum or glassy carbon crucibles as well as high flux-to-sample ratios. Additionally, the existing methods used for dissolving the fusion cake may cause boron loss. To achieve full dissolution and effectively prevent B loss, this study reports an improved alkali fusion method using sodium hydroxide and silver crucibles with a low flux-to-sample mass ratio of 5:1. Full dissolution was achieved through gentle heating in the presence of water combined with a stepwise dissolution procedure, which effectively prevented B loss during the dissolution of the fused alkaline cake. Using this improved procedure for dissolution, Amberlite IRA743 B-specific resin for B purification, and a multi-collector inductively coupled plasma mass spectrometer (MCICP- MS) for isotope analysis, we report boron isotope compositions and concentrations data for five silicate international standards. The results are consistent with the published data within analytical uncertainties. This safe and efficient method will greatly facilitate B isotope research of silicates. Related Articles | Metrics | Comments（0）

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Sedimentary Characteristics of the Triassic Karamay Formation in the North Hongshanzui Area, Junggar Basin WANG Jin, YU Xinghe, LU Fenghao, NIU Xiaojun, YE Zhaorui, YANG xintao Geological Journal of China Universities    2023, 29 (5): 776-787.   DOI: 10.16108/j.issn1006-7493.2022024 Abstract （485）      PDF（pc） （6278KB）（1266）       Knowledge map    Save The obvious sedimentary differences can be found between the upper and lower parts of the Karamay Formation in the north of Hongshanzui. To determine the sedimentary characteristics of the Karamay Formation, the seismic, core logging, and analytical data were used to analyze the rock and mineral characteristics, typical lithofacies, and sedimentary facies of the Karamay Formation. The results show that the lower Karamay Formation is characterized by the braided river deposits with obvious traction-current deposition, which is mainly composed of braided channel (Gi → St → Sp → (Sh) → Md), braided bar (St→Sp↔Sm), and alluvial plain (Mr↔Md → Fr). The channel sand-bodies are banded and mostly isolated from thick mudstone. The upper Karamay Formation is dominated by fan-delta with debris flow, density flow and tractioncurrent deposits. The braided channel (Gmm→Gcm→Gi→Sh), braided distributary channel (Gcm→Gi↔Gt) and braided bar (Gp↔Gi→Gcm) are developed in the fan-delta plain. The underwater distributary channel (Gi→Gt→Gp→St), mouth bar (Md→Sp↔Sw) and interdistributary bay (Md↔Sc) are developed in the fan-delta front. The thick stacked sandy conglomerate bodies are scours and overlap with each other and also characterized by good connectivity and broad distribution. The transformation from the braided river to fan-delta in the Karamay Formation is mainly controlled by the forwarded provenance system and increased supply capacity, the transition of the paleoclimate from arid and semi-arid to sub-humid and humid, and the lake level rise.  Related Articles | Metrics | Comments（0）

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Advance in Laser Raman Spectroscopy Carbon Geothermometer and Its Application in Earth Sciences CHEN Yiyi, WANG Bo, LIU Jiashuo, LU Shenghua, COCHELIN Bryan Geological Journal of China Universities    2023, 29 (6): 908-923.   DOI: 10.16108/j.issn1006-7493.2021116 Abstract （407）      PDF（pc） （1310KB）（1246）       Knowledge map    Save Organic matter is usually enriched in sediments, and will be transformed from disordered carbonaceous material to fully-ordered crystalline graphite, after being buried and heated to some high temperature during metamorphism. The crystalline order is closely corresponding to the certain temperature condition of metamorphism. The Raman spectroscopy (RS) can reflect the vibrational modes of molecules of carbonaceous material (CM), and to reveal the crystalline degrees of graphite, and thus the metamorphic conditions. The RSCM method is an empirical geothermometer by obtaining and analyzing the Raman parameters like band position, peak intensity, band area and FWHM (full width at half maximum) of carbon or graphite grains from a series of metamorphic samples, whose metamorphic temperatures are already known or can be calculated by other methods. A close correlation between the RSCM and peak metamorphic temperature is very well defined, so as to quantitively calculate the peak temperature of the unknown samples during regional or contact metamorphism. Based on the comparisons with the traditional geothermometers, it is suggested that the RSCM is practicable and reliable, and it shows several advantages such as high efficiency, in situ and nondestructive measurements, wide range of temperature detection, high sensitivity to CM inner structures, being free from later retrograde metamorphism, and wide fields of application. Thus, this method is significant for the reconstruction of regional tectonic and thermal evolution, and crustal thermal state. This paper reviews the study history of the RSCM, introduces the theory on CM Raman spectrum band distribution and its relationship with metamorphic temperature, summarizes some representative studies of natural graphitic carbons by Raman spectroscopy in recent years, and its applications in different fields of Earth Sciences. The research foreground of RSCM is finally prospected. Related Articles | Metrics | Comments（0）

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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 （3088）      PDF（pc） （11167KB）（1228）       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 | Comments（0）

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Spatial Entity-Text Information Matching for Geological Surveys Based on Siamese Network with Attention Mechanism QIU Qinjun, MA Kai, XIE Zhong, TAO Liufeng, HUANG Bo Geological Journal of China Universities    2023, 29 (3): 337-344.   DOI: 10.16108/j.issn1006-7493.2023025 Abstract （1004）      PDF（pc） （1534KB）（1166）       Knowledge map    Save Association matching of geological objects with different sources and representation of their structures, attributes and semantic relationships by models is an important support for later tasks such as semantic query and clustering. In this paper, we propose a twin network geological survey spatial entities and text description information association matching model based on attention mechanism for the problems of semantic heterogeneity and expression differences between geological survey spatial entities and external text descriptions. First, the attribute information of geological survey spatial entities is converted into text paragraphs, and the text semantics of geological spatial entities is encoded with the basic granularity of sentence vectors; then the two types of text objects are mapped into a unified vector space and input to the twin network for feature learning, and finally the experimental evaluation of model performance is conducted on the constructed real dataset. The results demonstrate that the model can better represent the sentence semantic information of geological survey spatial entities, and its recognition F1 value is improved by 8.4 percentage points compared with the benchmark experiment, which is better than the selected comparison method. Related Articles | Metrics | Comments（0）

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Equilibrium Isotope Fractionation Effect between Zn-containing Minerals and Aqueous Solution in Contaminated Soils HE Hongtao, GU Yifan, XING Lecai, WANG Yanfang, YANG Yang, CAI Xingping, HE Yuyang Geological Journal of China Universities    2024, 30 (03): 297-311.   DOI: 10.16108/j.issn1006-7493.2024006 Abstract （1530）      PDF（pc） （1441KB）（1153）       Knowledge map    Save Zinc (Zn) isotope fractionation, resulting from multiple physicochemical processes under Earth’s surface conditions, confounds the source identification of pollutants. The determination of Zn isotope fractionation factors between typical Zncontaining minerals and aqueous solutions in contaminated soils is crucial to trace Zn sources using isotopic tools. In this study, we used density functional theory based first principles calculations to investigate the most stable geometries of Zn-containing species, including hydrated Zn2+ complexes, Zn in hydroxy-interlayered minerals (Zn-HIM), Zn-rich phyllosilicates (Talc), Zn-layered double hydroxide (Zn-LDH), and surface adsorbed Zn2+. Based on these optimized configurations, we calculated the equilibrium isotope fractionation factors between the aforementioned structures and Zn2+ in aqueous phases. Our results showed that adsorbed Ⅵ Zn2+ is slightly enriched in 64Zn (Δ66/64Zn=-0.29‰~-0.20‰ ), while adsorbed Ⅳ Zn2+ is enriched in 66Zn (Δ66/64Zn =0.45 ‰~0.73‰ ). Secondary mineral phases are evidently enriched in 66Zn (Δ66/64Zn=0.51‰~1.11‰ ), if Zn transferred to stable crystalline precipitates. Using obtained fractionation factors, we successfully simulated the evolution trends of Zn isotope composition under the influence of single pollution sources (electroplating waste, sphalerite ore, emissions and metallurgical sludge) in equilibrium and Rayleigh fractionation modes. By comparing with available isotope data, these trends facilitate to find out the main source of Zn in contaminated soils. Related Articles | Metrics | Comments（0）

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End Member Model Analysis of Sediments Grain-size from Erlongwan Maar Lake and Corresponding Environmental Implication in the Past 100 Years LIAO Dongxia, GUO Haiting, WU Mengmeng, PAN Shaoming Geological Journal of China Universities    2023, 29 (2): 316-324.   DOI: 10.16108/j.issn1006-7493.2021051 Abstract （1466）      PDF（pc） （1623KB）（1136）       Knowledge map    Save Sediment grain size contains paleo-environmental information such as regional precipitation intensity, water level fluctuation and sediment provenance. The end-member modeling analysis can extract the end members representing different sedimentary dynamic processes. We collected two sediment cores from the center and the shore of the Erlongwan Maar Lake. 137Cs activities were measured by Coaxial High Purity Germanium Detector GMX30P-A Series, particle size was measured by the Malvern Mastersizer 2000. The parametric EMA modeling was used to analyze the grain size data of sediment cores in Erlongwan Maar Lake. Based on the results, we analyzed the sediment source and the sedimentary environment of Erlongwan Maar Lake in the past 100 years. The results indicate that the parametric EMA modeling has recognized three end members. The sediments in Erlongwan Maar Lake are thought to be aqueous mainly, and the eolian deposits are relatively less. From EM1 to EM3, the mode particle size increases successively. EM1 represents eolian deposits and fine-grained materials carried into the lake by flowing water. EM2 comes from the erosion of debris in the basin by surface runoff, which is the major component of sediments. EM1 and EM2 indicate a closed lake sedimentary environment with weak hydrodynamics, and EM3 indicates a process of strong surface runoff transport. The detrital material derived from continent is the main source of sediments. The distant clayey particles carried by the upper westerly wind and the near dust particles carried by meso-scale regional wind also contribute to the sediments. The sedimentary environment is relatively stable during recent 100 years. The sedimentation rate of the lake core is lower than that of the lakeshore. After 1963, the content of fine-grained materials increased, while the proportion of coarse-grained components decreased. This means the improvement of ecological environmental and the decrease of surface materials loss, which indicates that the establishment of Jilin Longwan National Nature Reserve plays an important role in soil and water conservation.  Related Articles | Metrics | Comments（0）

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Early Cretaceous Large-scale Reworking of the Juvenile Crust in North Qinling: Geochemical Composition and Genesis of the Huanghuaman Pluton QI Zeqiu, YU Yang, ZHAO Jingxin, GE Dongli, HE Jun, CHEN Fukun Geological Journal of China Universities    2023, 29 (6): 831-846.   DOI: 10.16108/j.issn1006-7493.2022046 Abstract （1430）      PDF（pc） （4319KB）（1107）       Knowledge map    Save The eastern Qinling orogen documents two magmatic episodes of granitoids in the Late Jurassic and Early Cretaceous. Their geochemical characteristics, being a petrologic probe for the composition and structure of the deep crust, are distinctly different, pointing to the complex magma sources. In this study, we report zircon U-Pb isotopic ages and whole-rock major and trace element contents and Sr-Nd-Pb isotopic compositions of the Huanghuaman pluton exposed in the eastern section of the North Qinling block. Zircon U-Pb ages indicate that the large-volume biotite monzogranite of the Huanghuaman pluton was emplaced during the 119 Ma to 117 Ma interval. The biotite monzogranites are enriched in large ion lithophile elements and light rare earth elements, but depleted in high field-strength elements and heavy rare earth elements, with significantly negative Eu anomalies and belong to the weakly peraluminous high-K calc-alkaline series. They are characterized by high radiogenic Pb isotopic compositions and relatively depleted Nd isotopic composition with initial εNd values of -5.7 to -4.1. These geochemical characteristics are remarkably different from those of the Late Jurassic granitoids within the North Qinling block and L ate Mesozoic granitoids within the southern margin of the North China block. The relatively depleted Nd isotopic composition of the Huanghuaman pluton is similar to those of the coeval Laojunshan in the eastern section and the Early Cretaceous Taibai granite in the western section of the North Qinling block, s uggesting that this block underwent large-scale reworking of the juvenile crust during the Early Cretaceous. The juvenile crustal materials might be derived from the mafic rocks within the North Qinling block or the subducted Neoproterozoic crustal rocks of the Yangtze and/or South Qinling blocks. These Early Cretaceous granitoids have different Nd isotopic compositions from those of the Late Jurassic Mangling and Muhuguan plutons in the North Qinling block, reflecting the compositional diversity of the granitoids that were derived from the deeply underlying, co mplex crustal materials. Related Articles | Metrics | Comments（0）