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    Genesis Process of the Cretaceous Daqushan Pluton in Zhejiang Province: Crystal-Melt Separation and Magmatic Recharge
    HE Chen, XIA Yan, XU Xisheng, QIU Jiansheng, XU Hang, ZHANG Zhi, ZHAO Sidi
    Geological Journal of China Universities    2023, 29 (5): 657-678.   DOI: 10.16108/j.issn1006-7493.2022018
    Abstract1185)      PDF (11167KB)(1053)       Save
    The models of trans-crustal magmatic system and crystal mush provide new insights into the study of Cretaceous magmatism in northeast China. The Daqushan pluton is located in the northeast of coastal Zhejiang and Fujian. It is mainly composed of K-feldspar granite with abundant melanocratic microgranular enclaves (MME) and is locally traversed by several mafic-intermediate dikes. A small outcrop of monzonite is exposed near the Chaotoumen. MME have a fine-grained texture with acicular apatites. Zircon U-Pb dating results show that the rock samples in the Daqushan pluton (including the K-feldspar granite, MME, monzonite, and mafic-intermediate dikes) crystallized at ~100 Ma. The K-feldspar granite are highly silicic (SiO2=68.45%-73.82%). While the miarolitic granite (DQS-7) without MME has the higher silica (76.27%), and its whole-rock geochemical and Sr-Nd isotope compositions are similar to those of coeval high silica granites (SiO2>75%) exposed around the Daqushan pluton. Daqushan K-feldspar granite bearing aggregates of plagioclase and K-feldspar exhibit“complementary”trace element geochemical characteristics with Daqushan miarolite and surrounding high silica granites. Further researches show that the Daqushan K-feldspar granite and miarolite were formed by felsic magma which originated from the partial melting of the ancient crustal basement and was recharged by mantle-derived magma. Such felsic magma underwent fractional crystallization and the extraction of high silica melt. Then, the residual silicic cumulate of the crystal mush and high silica melt crystallized and formed the Daqushan K-feldspar granite, miarolite and the surrounding coeval high silica granites. The mafic dikes of Daqushan are enriched in LILEs and depleted in HFSEs
    and are derived from the partial melting of the enriched mantle metasomatized by subducted dehydration fluids. The results of EPMA analyses indicate that the plagioclase in the K-feldspar granite and MME has a core-mantle-rim texture with low- An in the core (27-36, 25-41) and rim (17-32, 18-26) and relatively high-An in the mantle (28-57, 27-65). Integration of the element geochemical characteristics and Sr-Nd-Hf isotopic results, monzonite and intermediate dikes should be the product of magma mixing of mantle-derived mafic magma and felsic magma, while MME are the product of magma mingling of the two endmembers. The results of the Al-in-hornblende geobarometer show that the crystallization depth of MME is 1.8- 3.0 km, hornblende in monzonite develops core-mantle-rim texture, the crystallization depth of hornblende core and mantle is 17.0-21.2 km, and the depth of hornblende rim is 1.9-4.5 km. Based on the study of the origin and genetic relationships of K-feldspar granite, MME, miarolite, monzonite and mafic-intermediate dikes, and compared with the surrounding coeval high silica granites, this study establishes a model of trans-crustal magmatic systems for Daqushan pluton. The rollback of the subducting paleo-Pacific plate, the back-arc extension in the coastal area and the upwelling of the asthenosphere led to the underplating of the mantle-derived mafic magma, and further induced the partial melting of basement rocks in the lower crust to produce felsic magma. The continuous recharge and heating of mantle-derived magma favor the existence of long-lived melt-bearing regions in magma chambers, promoting magma differentiation and crystal-melt separation and thus forming two magma chambers with depths of 17-21 km and 2-3 km, respectively. K-feldspar granite, high silica granites, monzonite, MME and intermediate-mafic dikes were formed by magma mingling/mixing and crystal-melt separation in two connected magma chambers at different depths.
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    One-stop Sharing and Service System for Geoscience Knowledge Graph
    ZHU Yunqiang, DAI Xiaoliang, YANG Jie, WANG Shu, SUN Kai, QIU Qinjun, LI Weirong, QI Yanmin, HU Lei, LYU Hairong, WANG Xinbing, ZHOU Chenghu
    Geological Journal of China Universities    2023, 29 (3): 325-336.   DOI: 10.16108/j.issn1006-7493.2023029
    Abstract1263)      PDF (7167KB)(699)       Save
    As the most effective way of knowledge organization and service at present, knowledge graph has become the cornerstone of artificial intelligence and has been widely used in semantic search, machine translation, information recommendation and so on. In the era of big data, there is an urgent need of Geoscience knowledge graphs for integrating, mining and analysis of scattered, multi-source and heterogeneous Geo-data and its unknown knowledge intelligent discovery. To promote the construction and application of Geoscience knowledge graphs, the Deep-time Digital Earth (DDE) International Big Science Program has taken knowledge graph as its one of the core research contents since its launch in 2019. After more than three years of construction, DDE has built a large number of Geoscience knowledge graphs, and it strong needs one-stop sharing and service system of these knowledge graphs. Firstly, this paper introduces the content framework, composition as well as characteristics of the DDE knowledge graphs. On this basis, the design of the one-stop sharing and service system for the Geoscience knowledge graph is designed that include the design of the system functional and technical architecture. Finally, the development and operation environment & tools, and key technologies of the system are discussed in detail. The practice has proved that the system can effectively realize the one-stop sharing and open access of DDE knowledge graphs. Meanwhile, it sets an example for other fields or domains’ knowledge graph integrating and sharing systems.
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    Grain-size Characteristics and Environmental Implication of Neogene Red Clays in the Chinese Loess Plateau
    LU Keke, CHEN Zhong, YANG Yanpeng, ZHANG Jialin, ZHAO Zhongqiang, XIA Dinghong, NI Chunzhong, SONG Yinxian, ZHANG Shitao
    Geological Journal of China Universities    2023, 29 (5): 713-725.   DOI: 10.16108/j.issn1006-7493.2022020
    Abstract190)      PDF (1237KB)(549)       Save
    The aeolian origin of red clays in the Loess Plateau has been unanimously recognized. The earliest red clay was found in the late Oligocene and early Miocene, indicating that the arid environment had been formed in the inland northwest of China at the end of Paleogene. The grain size characteristics of red clay in the loess plateau show that the average grain size gradually decreases from the north to the south, indicatin g that the initial monsoon system has been established, and the winter wind played an important role in the transport of aeolian dust. The grain size distribution of red clay indiactes that it is composed of two components. The coarse grain (>20 μm) represents those transported by the near surface wind (winter wind), while the fine grain (<5 μm) represents those transported by the upper westerly wind. The grain size composition characteristics of red clays well record the development and change of atmospheric circulation. Since the end of Oligocene, the average grain size and sedimentation rate of red clays in the west of Liupanshan Mountain increased at 21.3-20.2 Ma, 16.0-13.3 Ma and 8.7-6.9 Ma, which may be related to global cooling and the Qinghai-Tibet Plateau uplift, and the 8.7- 6.9 Ma increase was mainly controlled by global cooling. In the red clay section to the east of Liupanshan, the grain size of variation characteristics shows that the grains deposited during 7.6 Ma to 6.2 Ma or to 5.4 Ma is coarse, indicating that the winter monsoon was strong. After that, the average particle size was fine up to 3.6 Ma, and the deposition rate was low, indicating that the winter monsoon was weak climate environment. From 3.6 Ma to 2.6 Ma, most profiles show an increase in mean grain size, an increase in sedimentation rates, and an increase in both winter and summer monsoon, which indicates to the transition to Quaternary glacial period. The development of the Arctic ice sheet and the uplift of the Qinghai-Tibet Plateau may have contributed to these changes.
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    The Petrogenesis of Baishuizhai Granitic Pluton and Its Significance to Uranium Mineralization in the Xiazhuang Area, Guangdong Province
    LI Kun, CHEN Weifeng, GAO Shuang, SHEN Weizhou, HUANG Guolong, LIU Wenquan, FU Shuncheng, LING Hongfei
    Geological Journal of China Universities    2023, 29 (4): 497-513.   DOI: 10.16108/j.issn1006-7493.2021117
    Abstract341)      PDF (2375KB)(535)       Save
    The Baishuizhai pluton is one of the main ore-bearing wall rocks of the Zutongjian uranium deposit in the northwestern part of the Xiazhuang granite-related uranium ore filed, yet its petrogenetic mechanisms and its relationship with uranium mineralization are still unclear. Thus, in this study, we present zircon SHRIMP U-Pb ages, whole-rocks and mineral geochemical data for the Baishuizhai granite. Field and petrographic investigations show that the Baishuizhai granitic pluton was emplaced into the Xiazhuang granitic batholith, mainly composed of fine-grained two-mica granite and muscovite granite, and the zircon SHRIMP U-Pb dating reveals that both granites were formed during the Indochina period with ages of 229.4 Ma and 231.8 Ma, respectively. They show typical peraluminous S-type granitic geochemical characteristics that are high SiO 2 contents, total alkalis contents and ACNK values ( ≥ 1.1), low FeOt+MgO+TiO 2 contents and P 2O 5 contents, enriched in Rb, Th and U, depleted in Ba, Sr, P and Ti, and enriched in aluminum-rich minerals. Compared with the Xiazhuang granite, both types of granites in the Baishuizhai pluton show enriched in inherited zircon, higher SiO 2 contents and Rb/Sr ratios, but lower FeOt+MgO+TiO 2 contents, P 2O 5 contents, Zr/Hf ratios, and Fe 2+/(Fe 2++Mg) ratios of biotites, indicating that they were derived from low partial melting of reducing material-rich feldspathic meta-pelites, and are not formed by the differentiation evolution of the parent magma of the mafic meta-pelites-derived Xiazhuang granite. Furthermore, compared with the two-mica granite, the muscovite granite display significant tetrad REE patterns, lower REE, Zr/Hf ratios and Eu/Eu* values, indicating that an interaction of F-rich fluids with the magma occurred in the formation of the muscovite granite. Both types of granites in the Baishuizhai granitic pluton are enriched in uranium and can be important uranium-bearing granites in the region. Relative to the 2-mica granite in the Baishuizhai pluton, the muscovite granite is more enriched in uranium and more favorable to be uranium source rocks for hydrothermal uranium mineralization.

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    Macroscopic and Mesoscopic Investigation on the Physical and Mechanical Characteristics of Coral Limestone at Different Depths
    MA Linjian, LIU Huachao, ZHANG Wei, LI Qi, ZHU Honghu, WU Jiawen
    Geological Journal of China Universities    2023, 29 (3): 471-478.   DOI: 10.16108/j.issn1006-7493.2021074
    Abstract1137)      PDF (2519KB)(532)       Save
    In order to investigate the physical and mechanical characteristics of coral reefs with different depth in the South China Sea, scanning electron microscopy (SEM) and X-ray tomography (CT) technology are used to characterize the micro morphology and internal pore structure characteristics of shallow and deep reef limestone. Quantitative relationships between P-wave velocity and porosity as well as density were established. Uniaxial compression tests on dry and saturated reef limestone were also carried out. Results show that shallow reef limestone is porous with excellent pore connectivity, and the main mineral composition is aragonite, which belongs to the biological sedimentary rock. While deep reef limestone is dense with poor pore connectivity, and the main mineral composition is calcite, belonging to the metamorphic rock. The porosity of deep reef limestone is about 1/10, with an average peak compressive strength of about 4.8 times and an average elastic modulus of about 4.5 times that of shallow reef limestone. Reef limestone belongs to soft or extremely soft rock, characterized by brittle destruction property. The typical damage pattern is multiple rupture surface destruction along the primary pore, growing line of corals and weak bond surface, with high  residual strength. The hydrogenic effect of reef limestone is significant, and the water rationality of deep reef limestone is stronger than shallow reef limestone. The significant difference of physical and mechanical performances in shallow and deep reef limestone are mainly due to the variety in mineral components, pore structure and lithology caused by the varying degree of rock cementation with different depths.

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    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
    Abstract131)      PDF (711KB)(481)       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. 
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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
    Abstract857)      PDF (3613KB)(472)       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.
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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
    Abstract251)      PDF (2723KB)(418)       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.
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    Construction of Nb-Ta Deposit Knowledge Graph and Its Application
    RAN Yizao, DONG Shaochun, WANG Rucheng, HU Huan, FANG Siyuan, CHANG Fengnian, KONG Jia
    Geological Journal of China Universities    2023, 29 (3): 359-371.   DOI: 10.16108/j.issn1006-7493.2021107
    Abstract803)      PDF (4845KB)(416)       Save
    As an important resource for emerging industries, critical metals have gradually gain attention both domestically and overseas in recent years. However there are still some bottlenecks existing in the critical metal research due to its low abundance, difficulty to trace, identify and separate. As an important infrastructure of big data and artificial intelligence, knowledge graph provides new insights to tackle these issues. Most of the research achievements related to critical metal deposits are published in academic journals, which are written in natural language and is difficult to be understood and directly used by machines. In this paper, the ontology layer of Nb-Ta deposit knowledge graph was constructed and data extracted from literatures consists of the fact layer of the Nb-Ta deposit knowledge graph. Based on the Nb-Ta deposit knowledge graph, the features and relationships among the metallogenic periods, types of Nb-Ta deposits and the co-occurrence of niobium and tantalum related minerals were analyzed. It will help to further reveal the spatio-temporal distribution and evolution characteristics of China Nb-Ta deposits. 
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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
    Abstract958)      PDF (1366KB)(383)       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.
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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
    Abstract876)      PDF (2348KB)(377)       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.
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    Deformation Prediction of Reservoir Landslides Using Knowledge Graph Optimized Kalman Filter
    HE Wangyan, ZHANG Wei, LI Houzhi, PAN Bo, DENG Lu, ZHU Honghu, SHI Bin
    Geological Journal of China Universities    2023, 29 (3): 372-381.   DOI: 10.16108/j.issn1006-7493.2022068
    Abstract878)      PDF (3065KB)(377)       Save
    Reservoir landslides occur frequently in the Three Gorges Reservoir area. Predicting the deformation of the landslides is an important measure to reduce the risk. This paper constructs a Chinese reservoir landslide knowledge graph combined with multivariate Taylor series Kalman filter and proposes a knowledge graph optimized Kalman filter model KG-MTKF. Taking the
    Xinpu landslide in Fengjie County in the Three Gorges Reservoir area as an example, the effectiveness of the model was verified by using on-site monitoring data. Results show that compared with the monitoring data, the multivariate Taylor series Kalman filter model (MT-KF) and the knowledge graph optimized Kalman filter model (KG-MTKF) show good consistency in the stationary stage when used to predict reservoir landslides. In the initial stage and step-like stage of the landslide deformation, the prediction accuracy of KG-MTKF is higher. The error of the two models in the initial stage is relatively large, which is caused by the small initial deformation value of the landslide and the more significant influence of system noise. The errors of the two models are
    relatively small in the step-like stage, the stationary stage, and the entire monitoring cycle, and KG-MTKF has higher accuracy than MT-KF. For nonlinear dynamic systems like Xinpu landslides, the KG-MTKF can maintain high accuracy and strong robustness at different positions and deformation stages.
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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
    Abstract882)      PDF (1153KB)(342)       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.
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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
    Abstract142)      PDF (6972KB)(338)       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. 
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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
    Abstract963)      PDF (7113KB)(327)       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.
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    Discrete Element Numerical Simulation of the Sspin Evolution Process of Rubble Pile Asteroids
    ZHANG Chenwei, LIU Chun, GENG Huan, LIU Hui
    Geological Journal of China Universities    2023, 29 (5): 743-755.   DOI: 10.16108/j.issn1006-7493.2022022
    Abstract89)      PDF (6890KB)(309)       Save
    In recent years, exploration research has shown that the rubble pile structure formed by gravity and cohesion may be an important method of asteroid formation. To explore the evolution mechanism of this kind of asteroid, this paper makes secondary developments based on the discrete element software MatDEM and realizes the calculation of the element’s gravitational force. A numerical model of a “rubble mound” asteroid with a diameter of 1.2 km is established, and the rotational remodelling and failure processes of spherical aggregates under different adhesion strength and bulk densities are analysed by numerical simulation. The results show that spherical aggregates are affected by the initial increment of angular velocity to start the remodelling process of aggregates, leading to deformation or failure. With the decrease in the adhesion strength, the model will be destroyed more easily. Before destruction, the asteroid will maintain the stability of its configuration by deforming into an oblate ellipsoid. The increase in bulk density effectively increases the structural stability of the asteroid model with a certain adhesion strength, can delay the occurrence of asteroid destruction, and the number of particles falling off decreases with the increase of density. Discrete element analysis can better simulate the spin evolution process of asteroids. Combined with real asteroid data, it is beneficial to explore the mechanism of asteroid spin evolution and destruction deeply and comprehensively. 
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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
    Abstract100)      PDF (1310KB)(306)       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.

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    Overview of New Taxa on Global Vertebrate Fossil during 2017-2021
    WANG Haohan, ZHU Min, SHI Xiaodong, PAN Zhaohui
    Geological Journal of China Universities    2023, 29 (5): 788-794.   DOI: 10.16108/j.issn1006-7493.2022026
    Abstract1115)      PDF (2181KB)(302)       Save
    Biodiversity data of vertebrate fossils is important information source for studying earth history and life evolution. The species list of vertebrate fossils is an essential basis for studying the diversity of global vertebrate fossils. Reviewing new taxa and literature on vertebrate fossils can reveal the research hotspots of vertebrate fossils diversity and grasp disciplinary development directions on a time scale. Based on the DeepBone Database, this study reviews the annual variation characteristics of taxa and literature, distribution countries of the holotype, published journals, and significant contributing institutions of new taxa on the different categories of global vertebrate fossils during 2017-2021 using bibliometrics analysis. The result shows that 2662 new taxa emerged, and 1946 literature were published on global vertebrate fossils during 2017-2021. New taxa and literature on vertebrate fossils have decreased since the outbreak of COVID-19 at the end of 2019. Countries with a high distribution of the holotype of new taxa for global vertebrate fossils during 2017-2021 and are rich in vertebrate fossil resources, are strong in the economic and scientific research, mainly including the United States, China, New Zealand, Argentina, and Germany. Journal of Vertebrate Paleontology, Cretaceous Research, Historical Biology, PeerJ, and Journal of Systematic Palaeontology are the prominent journals

    on new taxa of vertebrate fossils. The institutions with a high contribution to the new taxa for vertebrate fossils are the Chinese Acad Sci, Russian Acad Sci, Consejo Nacl Invest Cient & Tecn, Nat Hist Museum, and the research cooperations of various institutions are very close. The study of taxonomy on vertebrate fossils in China has reached a high level in the world. We should continue to strengthen the accumulation of primary data on vertebrate fossils diversity to provide the DeepBone database for exploring the origin and evolution of bio diversity in the future. 

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    Sr-Nd-Pb Isotopic Composition of the Chinese National Standard Igneous Rock Powders Measured by the Thermal Ionization Mass Spectrometry
    WANG Zhiyi, CHENG Hong, ZHAO Jingxin, YE Risheng, LI Weiyong, HE Jianfeng, CHEN Fukun
    Geological Journal of China Universities    2023, 29 (5): 679-692.   DOI: 10.16108/j.issn1006-7493.2022017
    Abstract133)      PDF (1003KB)(290)       Save
    In this study, Sr-Nd-Pb isotopic compositions of three Chinese national igneous rock standard materials, GSR-1 granite, GSR-2 andesite, and GSR-3 basalt, were measured by means of the techniques of the isotopic dilution and the thermal ionization mass spectrometry, to investigate the homogeneity of their isotopic compositions and the suitability for the usage as rock standard materials. Three international rock standard materials, BCR-2 basalt, BHVO-2 basalt, and AGV-2 andesite, produced by the US Geological Survey, were simultaneously analyzed as reference materials to check the reliability of the analytical procedures. The analytical results show that three national standard materials of igneous rocks have homogeneous Sr and Nd isotopic compositions. Compared to the GSR-1 granite, the GSR-2 andesite and GSR-3 basalt yield homogeneous Pb isotopic compositions. Relatively large variation in Pb isotopic composition of the GSR-1 granite might be caused by the addition of radiogenic Pb isotopes from those minerals having high U and Th contents. On the basis of the analytical results reported in this study, it is suggested that the three national standard materials of igneous rock powders are suitable as the reference materials for the Sr and Nd isotopic measurements and, the GSR-2 andesite and GSR-3 basalt are also the ideal candidates as reference materials f or the Pb isotopic analysis.
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    Analysis of Deformation Characteristics and Parameters of Clay Layers in South Subsidence Area of Beijing
    YOU Binhao, YE Shujun, TIAN Fang, LUO Yong
    Geological Journal of China Universities    2023, 29 (4): 590-599.   DOI: 10.16108/j.issn1006-7493.2021083
    Abstract2529)      PDF (2292KB)(275)       Save
    The land subsidence in Beijing is divided into north and south areas, and the southern area mainly includes Lixian-Yufa subsidence zone. The subsidence rate in this area has accelerated in recent years and reached 50-75 mm/a during 2017-2019, showing new subsidence characteristics. Based on the subsidence and water level observation data of 7-year time series from 2011 to 2017 at Yufa Subsidence Monitoring Station, the only subsidence observation station in the south subsidence area. The deformation characteristics of soil layers, especially clay layers, are systematically analyzed. Then the elastic and inelastic specific storage, vertical hydraulic conductivities and deformation lag time of the clay layers are estimated by the stress-strain diagram method and the type curve method. The results show that there are both elastic deformation and plastic deformation in each soil layer, and the plastic deformation is the main deformation with obvious deformation hysteresis. However, the deformation rate of each soil layer presents different characteristics. The results of the stress-strain diagram method show that the inelastic specific storage of the first and second clay layers is between 1.49×10 -5 and 2.10×10 -5, the elastic specific storage is between 3.93×10 -5 and 8.38×10 -5, the inelastic specific storage is 2-4 times of the elastic specific storage, the vertical hydraulic conductivity is between 6.20×10 -6~4.39×10 -5 m/d, and the soil deformation lag time is 2.1-12.8 years. The specific storage of the shallow layers in the study area estimated by the type curve method is about 4.8×10 -4, and that of the deep layer is between 1.08×10 -4 and 2.05×10 -4. The specific storage of shallow layer is 2-4 times of that of deep layer, and the vertical hydraulic conductivities are 1-2 orders of magnitude larger than that of the deep layers.
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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
    Abstract825)      PDF (1534KB)(273)       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.
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    Influence of Fuel Pollution on Hydrogeological Parameters of Porous Media
    YANG Pengfei, CHEN Yudao, JIANG Yaping, YAN Jianing, ZHENG Gao, ZOU Zhikun, LIU Quan, QIN Jiaxiao
    Geological Journal of China Universities    2023, 29 (4): 608-616.   DOI: 10.16108/j.issn1006-7493.2021108
    Abstract1724)      PDF (1695KB)(269)       Save
    Influence of fuel pollution on groundwater environment is an important subject. Investigating the hydrogeological parameters of contaminated sites will be helpful to understand the changes of hydrogeological parameters before and after pollution, as well as changes of the migration behavior of contaminants in groundwater. To compare the differences of parameters before and after gasoline contamination and evaluate the impacts of gasoline contamination on hydrogeological parameters, three stages of quantitative tracer experiments in sand-tank were performed. The results show that: (1) the accumulation of gasoline contamination leads to the occurrence of bioclogging, and the degree of bioclogging tends to slow down with the increasing percolation distance; there exist differences in solute dispersion in different regions of porous media, and increased solute flux in the dominant flow on the central line and the mass recovery rate ; the solute Breakthrough Curves show a lean-high pattern and a clear trailing. (2) by monitoring the gasoline contamination for 6 years, it is found that the permeability coefficients of traditional gasoline tank (TG-tank) and ethanol gasoline tank (EG-tank) were 25.4 and 20.5 m/d, respectively, which decreased to 61% and 49% of the initial permeability coefficient KII before the sand tank was contaminated; the effective porosity of TG-tank and EGtank was reduced from the initial value of 0.30 to 0.28 and 0.26, respectively. Hydrodynamic dispersion coefficient also tended to decrease. The permeability of porous media is reduced more significantly by ethanol gasoline pollution. The accumulation of organic contamination will change the hydrogeological parameters of the contaminated site, and strengthening studies of hydrogeological parameters after contamination can provide a reasonable basis for evaluating the contamination risk.
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    Mechanisms of Ce(III) Oxidation and Fixation by Coexisting Iron and Manganese Oxides
    ZHAO Hanyue, ZHOU Yuefei, LI Xiaosong, XIE Qiaoqin, CHEN Tianhu
    Geological Journal of China Universities    2023, 29 (5): 705-712.   DOI: 10.16108/j.issn1006-7493.2022031
    Abstract135)      PDF (887KB)(267)       Save
    In this study, we conducted bulk and dynamic experiments to investigate the efficiency of Ce (III) oxidation and fixation by Mn-contained limonite and goethite. Based on experimental results, the mechanism of Ce oxidation and fixation by coexisting iron and manganese, and its geological significance, are discussed. Results of bulk experiments show that Mn-contained limonite has a high performance on the oxidation and fixation of Ce; Ce was totally removed after 48 hours under solution with Ce concentration of 6000 μg/L and limonite concentration of 1 g/L. For experiments with initial Ce concentrations of 300 to 4500 μg/L, Ce removal is positively correlated with Mn content for limonite experiments. As for goethite, it decreased Ce removal when comparing to the control experiments. Results of dynamic adsorption experiments show that for high-Mn limonite, the distribution of Ce is constrained not by Mn minerals, but by iron oxides. The results of this study indicates that: (1) the process of Ce oxidation and precipitation is adsorption of Ce (III) -oxidation of Ce(III) to Ce(IV)-precipitation of Ce(IV) minerals-autocatalytic oxidation of Ce(III) to Ce(IV) by CeO 2, and (2) the contributions of coexisted Mn and Fe oxides to Ce oxidation and fixation are Mn oxides promoting the oxidation of Ce(III) and Fe oxides promoting the precipitation of CeO 2 through electrostatic attraction. This study is significant in explaining the geological phenomenon that although Mn oxides have higher Ce(III) oxidation ability than that of Fe oxides, under Fe- and Mn-oxides coexisting conditions, Ce tends to be fixed by Fe oxides.
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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
    Abstract873)      PDF (4406KB)(267)       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.
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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
    Abstract1000)      PDF (2285KB)(260)       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.
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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
    Abstract143)      PDF (4319KB)(245)       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.
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    Study on Optical Fiber Temperature Measurements and Ground Temperature Changes in Pumping and Irrigation Wells of Carbonate Thermal Storage
    SHI Qipeng, TAN Xianfeng, MENG Jia, ZHENG Huiming, ZHANG Xi, LIU Xiao, SONG Shuailiang, DU Ying
    Geological Journal of China Universities    2023, 29 (5): 756-765.   DOI: 10.16108/j.issn1006-7493.2022013
    Abstract159)      PDF (1505KB)(223)       Save

    Carbonate thermal reservoirs have the characteristics of rich geothermal resources, good mining conditions and large water inflow of single wells, and represent one type of the main thermal reservoirs for the development and utilization of middle and deep geothermal resources. In the process of long-term geothermal exploitation and tail water reinjection, it is necessary to maintain the hydraulic connection between pumping and irrigation wells to avoid thermal breakthrough, The long-term monitoring of thermal reservoir temperature, analysis, and calculation of heat sources in pumping and irrigation wells are important topics for sustainable development and utilization of geothermal resources. This paper introduces the distributed optical fiber temperature measurement technology of pumping and irrigation wells, monitors the influence of pumping and reinjection of carbonate thermal storage on ground temperature, and analyzes the heat sources and quantity of heat storage temperature recovery using the monitoring data. The results show that (1) the heat storage temperature of the pumping well decreased significantly on the sixth day after heating with an average decrease of 1.6 ℃、 which was affected by the small spacing of pumping and irrigation wells and the dominant channel of carbonate heat reservoir, and the pumping and irrigation well produced a thermal breakthrough; the heat storage temperature of the reinjection well failed to recover to the initial temperature before the second heating season due to a large amount of low-temperature tail water reinjection for a long time, and the temperature of pumping well basically recovered. Analysis reveals that the main source of reservoir heat recovery is geothermal water convection and heat accumulation, followed by high-temperature reservoir and geothermal water conduction and heat accumulation. The results of this study show that under the condition of large-scale reinjection, the temperature of reinjection well decreases and the thermal breakthrough of pumping and irrigation well is an inevitable development trend. In order to promote the sustainable development and utilization of geothermal resources, it is very necessary to study the appropriate well spacing of pumping and irrigation wells to prevent thermal breakthrough in a short timescale.

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    Petrogenesis and Geologic Implication of the Late Paleoproterozoic A-type Xiaohe Pluton along the Southern Margin of the North China Craton
    WANG Meixuan, WANG Zhiyi, ZHAO Jingxin, QI Zeqiu, HE Jun, CHEN Fukun
    Geological Journal of China Universities    2023, 29 (6): 809-830.   DOI: 10.16108/j.issn1006-7493.2022053
    Abstract132)      PDF (3050KB)(217)       Save
    Paleoproterozoic granitoids in the southern margin of the North China Craton are important carriers for studying the crustal evolution in Precambrian. In this study, we report zircon U-Pb ages and whole-rock geochemical compositions of the Xiaohe pluton exposed along the southern margin of the North China Craton in order to discuss its petrogenesis and significance for Precambrian crustal evolution. The Xiaohe pluton is composed of biotite-bearing monzogranite, geochemically, which can be divided into two categories according to its rare earth element characteristics. Type I shows the right dip distribution mode of light rare earth elements enrichment and heavy rare earth elements depletion, which has the characteristics of medium differentiation. Type II has a distribution pattern of rare earth elements with low total rare earth elements, insignificant fractionation of light and heavy rare earth elements, and depletion of middle rare earth elements, which has the characteristics of high differentiation. The zircon U-Pb dating on these two types of granite yielded ~1.80 Ga ages for the emplacement time of the magmas, indicating both of them emplaced in single magmatic period. All the analyzed rocks are rich in silica and alkaline and weakly peraluminous, having high-K alkali-calcareous and calc-alkaline characteristics. They are enriched in Rb, Th, U, K, etc., but depleted in Ba, Sr, P, and Ti. Both types granites have similar Nd-Hf isotopic compositions and their magmas should originate from partial melting of the Late Archean basement rocks along the southern margin of the North China Craton. The magmatism of A-type granite probably represents the tectonicsthermal event closely related to extension, implying a post-collisional/post-orogenic extensional setting along the southern margin of the North China Craton at ca. 1.80 Ga. 
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    Identification of Early Cretaceous Dioritic Enclave of Guposhan Granite in Guangxi and Its Geological Significances
    LIU Fenglei, ZHOU Yun, SHI Shuiping, FENG Zuohai, CAI Yongfeng, FU Wei, ZHAO Kai
    Geological Journal of China Universities    2023, 29 (3): 455-470.   DOI: 10.16108/j.issn1006-7493.2021077
    Abstract109)      PDF (3195KB)(217)       Save
    In order to figure out the Mesozoic tectonic evolution of the northeastern Guangxi, this paper presented detailed petrological, chronological and geochemical data on the Guposhan composite rock mass and its dioritic enclaves. The chronological results show that the formation age of the dioritic enclaves is 142±1 Ma, for the first time to identify Early Cretaceous dioritic enclaves in this area. Elemental geochemical analysis results show that the contents of SiO 2, MgO and Fe 2O 3 T of the dioritic enclaves are 55.66%-56.72%, 2.26%-2.30% and 10.43%-10.77%, respectively; the contents of SiO 2, MgO and Fe 2O 3 T of the host granite sample are 68.33%-68.67%, 0.60%-0.64% and 3.73%-3.89%, respectively. The granites are characterized by high 10000*Ga/Al ratios and Zr+Nb+Ce+Y contents, similar with those of A-type granite. Both the host rock and the dioritic enclave are enriched in large ion lithophile elements and high field strength elements. The above data indicate that the dioritic enclaves are produced by magmatic mixing, and their formation is related to extension and thinning of the lithosphere in the Late Mesozoic. Together with regional geological data, it is suggested that the Mesozoic extension of the lithosphere in South China was episodic, which led to the development of multi-stage magmatism in South China.
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    Meso-Cenozoic Uplift and Transformation of Tectonic Extension Mode in the Eastern Margin of Qinghai-Tibet Plateau
    JIN Wenzheng, BAI Wankui, YE Zhixu
    Geological Journal of China Universities    2023, 29 (6): 872-885.   DOI: 10.16108/j.issn1006-7493.2022057
    Abstract613)      PDF (1532KB)(215)       Save
    In order to analyze changes in of tectonic deformation and extension mode during the process of eastward compression of Qinghai-Tibet Plateau, the eastern edge of Qinghai-Tibet Plateau is selected as the study area, and apatite/zircon fission track studies were carried out. The results show that many differences between the Zoige Basin and the Longmenshan Block in the aspect of low-temperature geochronology and tectonic uplift: the cooling rates of several samples in the Zoige basin are relatively stable, ranging from 1.257 ℃ to 1.285 ℃ /Myr, while the cooling rates of several samples in the Longmenshan Block changes greatly, ranging from 1.243 ℃ to 2.875 ℃ /Myr; Zoige Basin has experienced two obvious tectonic thermal events since 100 Ma with the first in 100-80 Ma (cooling rate is 4.40±0.395 ℃ /Myr) and the second in 21-12 Ma (cooling rate is 2.89±0.597 ℃ /Myr). The eastern edge of Longmenshan Block has generally shown a gradual increase in the degree of tectonic uplift since 70 Ma, and the uplift has continued to increase since 8 Ma with the cooling rate of 5.75±0.238 ℃ /Myr; The tectonic deformation of Zoige Basin can be classified as forward expansion, while the Longmenshan Block has backward expansion (especially since 8 Ma). The process mentioned above is summarized a“s reflection and refraction of tectonic expansion”, the“ reflection tectonic stress”reached current location of Longriba fault in Pliocene (about 4.48 Ma), with the result of the Longriba fault zone with the features of both thrust and dextral strike slip.
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