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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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    Progress of Methods for Assessing CO 2 Mineralization Storage Potential in Basalt
    GAO Zhihao, XIA Changyou, LIAO Songlin, YU Xiaojie, LIU Muxin, LI Pengchun, LIANG Xi, DAI Qing, HUANG Xinwo
    Geological Journal of China Universities    2023, 29 (1): 66-75.   DOI: 10.16108/j.issn1006-7493.2022099
    Abstract2089)      PDF (1109KB)(667)       Save
    CO 2 geological storage is an important technology to reduce CO 2 emissions, which can safely store CO 2 in geological formations for millions of years. Conventional CO 2 storage reservoirs include deep saline aquifers and depleted oil and gas reservoirs. Basalt is a new type of CO 2 storage reservoir that has been attracting attention in recent years. CO 2 storage in basalt would increase the technical method and potential of CO 2 geological storage. Storage potential assessment is one of the fundamental works of CO 2 geological storage study. This paper systematically examines the current methods for assessing the storage potential of CO 2 in basaltic rocks, and analyzes the principles and application scenarios of various methods. Then, the study takes the basalt of Icelandic Active Rift zone as an example to compare each of the methods. The study suggests that the current CO 2 mineralization storage potential assessment methods generally include three categories: ① Unit rock storage potential assessment method, which evaluates carbon sequestration potential based on the reaction volume or area of rocks; ② Mineral replacement storage potential assessment method: based on the volume of minerals that can react with CO 2 in basalts. ③Pore filling storage potential assessment method, which evaluates the proportion of secondary minerals that can fill reservoirs’ pore space after CO 2 mineralization. The authors note that the first method requires special experimental analysis, making it more challenging, the second method is more appropriat for basalts with high porosity and low reactive mineral content, while the third method is more suitable for basqlts with low porosity and high reactive mineral content.
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    Status and Advances of Research on Caprock Sealing Properties of CO 2 Geological Storage
    CHEN Bowen, WANG Rui, LI Qi, ZHOU Yinbang, TAN Yongsheng, DAI Quanqi, ZHANG Yao
    Geological Journal of China Universities    2023, 29 (1): 85-99.   DOI: 10.16108/j.issn1006-7493.2023010
    Abstract1626)      PDF (6425KB)(654)       Save
    CO 2 Geological storage is one of the key technologies to address global climate changes and reduce greenhouse gas emissions. Large-scale CO 2 injection into the formation is prone to inducing CO 2 leakage problem. In particular, the leakage problem of CO 2 through caprock includes capillary leakage, hydraulic fracture and leakage along pre-existing faults crossing caprock. Therefore, evaluation of caprock seal is crucial for prediction of long-term safety and stability of CO 2 geological storage. This paper provides an overview of the current status of research on sealing mechanisms, influencing factors, and damage modes affecting caprock seal of CO 2 geological storage. It is concluded that caprock seal mechanisms include capillary seal, hydraulic seal, and overpressure seal. The main influencing factors of caprock seal characteristics include caprock lithology, mudrock-sand ratio, caprock mechanical properties, and sequestration pressure. Then, the damage modes of caprock seal during CO 2 injection are illustrated, and some insight into the shortcoming of caprock seal is provided.
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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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    Active Source Seismic First-arrival Pickup Method Based on Small Sample Convolutional Neural Network
    YU Zhihan, WANG Tao, SUN Pengyuan, WANG Wenchuang, GUO Zhenbo
    Geological Journal of China Universities    2022, 28 (3): 414-423.   DOI: 10.16108/j.issn1006-7493.2021060
    Abstract356)      PDF (3646KB)(521)       Save
    The interpretation of seismic travel-time imaging depends on the accuracy of picking up first arrivals, and it is low efficiency and high cost to pick up arrivals manually. Previous studies showed that deep learning can be applied for automatically picking, but the methods often need a large number of arrivals as the training set. In this study, we trained the U-Net with multichannel images and found that the root mean square error (RMSE) of first P arrivals decreases with the increase in the number of training sets. The errors of 35 and 597 shots are 11.4 and 6.5 ms, respectively. Referring to data augmentation methods in semisupervised
    learning, we selected methods (Random Crop, Random Erase, etc.) suitable for seismic data and applied them to the training set. After random erase of the training sets of 35 shots, the RMSE is less than 5.5 ms (about 3 sampling points), which is 51% less than the error with the original training set. Compared with previous deep learning methods, the augmentation methods can be implemented to pick up the first arrivals with higher precision in the case of small samples.
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    Current Status and Recommendations of Offshore CO 2 Geological Storage Monitoring
    LI Qi, LI Yanzun, XU Xiaoyi, LI Xiaochun, LIU Guizhen, YU Hang, TAN Yongsheng
    Geological Journal of China Universities    2023, 29 (1): 1-12.   DOI: 10.16108/j.issn1006-7493.2023008
    Abstract2458)      PDF (1583KB)(520)       Save
    Marine carbon dioxide (CO 2) storage is an important means to cope with greenhouse gas emissions in China’s coastal areas, and is an indispensable key technology to achieve the goal of “emission peak and carbon neutrality”. The coastal areas of China are industrially developed and rich in carbon sources. Owing to the good physical properties and reservoirs and trap characteristics, offshore basins have huge storage potential. At present, the first marine demonstration project of China has been officially launched in the Pearl River Estuary Basin in the South China Sea. As an important part of CCUS technology, CO 2 monitoring runs through the whole life cycle of CO 2 geological storage and is a necessary method to ensure the safety and rationality of storage works. However, China’s CO 2 marine storage technology is in its infancy, and the task of marine storage monitoring is quite challenging. For this reason, this paper reviews the relevant representative research and demonstration project cases of international CO 2 marine storages, summarizes the monitoring indicators, technologies and schemes, and puts forward the screening and optimization methods of monitoring CO 2 marine storage and suggestions for monitoring technology. The outcome of this study provides a reference for the development of CO 2 marine storage demonstration projects in China.

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    Development of Teaching Philosophy and Reform of Introduction to Earth Science
    DAI Jingen, YAN Danping, QIU Liang, CAO Xiuhua
    Geological Journal of China Universities    2022, 28 (3): 352-356.   DOI: 10.16108/j.issn1006-7493.2021092
    Abstract399)      PDF (1502KB)(511)       Save
    “Introduction to Earth Science” is a basic disciplinary course and also the first professional course for junior students major in geology. It undertakes important tasks such as constructing a professional knowledge framework and cultivating interest of students in earth sciences. This paper systematically introduces the development process and achievements of “Introduction to Earth Science” at China University of Geosciences (Beijing), and focuses on the formation process and implementation effects of four teaching concepts such as “teaching the talents”. This paper also emphasizes that high-level teaching team is critical for curriculum construction. After years of teaching practice, a modular teaching system has been proposed, which highlights the key chapters but also has systematic effect. In terms of curriculum design, theoretical and practical lessons have the same amounts of classes, implying the practical characteristics of the course. The teaching method has gradually transitioned from classroom teaching in the past to a combination of classroom teaching, indoor and field geological practice, online learning, and virtual simulation of field practice. The reform and construction of the above-mentioned curriculum system in our university will provide some references for similar courses in related universities.
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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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    Hirnantian (latest Ordovician) Stratigraphy and Palaeogeography of the Western Yangtze Platform, South China
    WANG Guangxu, WEI Xin, CUI Yunong, ZHANG Xiaole, WANG Qian, ZHAN Renbin
    Geological Journal of China Universities    2023, 29 (2): 298-315.   DOI: 10.16108/j.issn1006- 7493.2022051
    Abstract1435)      PDF (20684KB)(477)       Save
    Hirnantian (latest Ordovician) rocks and fossils have still not been sufficiently documented in the western Yangtze region of South China (today’s southwestern Sichuan and northeastern Yunnan provinces, Southwest China). Compilation of published and new data results in refined Hirnantian stratigraphy and palaeogeography of the region. The lower Hirnantian is typified by the dark-grey cacareous mudstone or argillaceous limestone of the Kuanyinchiao Formation yielding cool-water Transitional Benthic Fauna 1 (TBF 1). The middle Hirnantian strata, however, can be grouped into a near-shore lithofacies belt with distinctive grainstones of the upper Kuanyinchiao Formation yielding warm-water TBF 2, and a more offshore belt characterized by black shales of the basal Lungmachi Formation. A similar facies differentiation occurs in the upper Hirnantian of the region, but the near-shore sediments are in places represented by TBF 3-bearing calcareous siltstones, for which a new lithostratigraphic unit, the Weiba Formation, is proposed. On this basis, refined Hirnantian paleogeographic reconstructions of the western Yangtze Platform are presented.
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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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    Ce-in-zircon Oxybarometer and the Redox State of the Early Earth
    XIAO Luyi, YANG Xiaozhi
    Geological Journal of China Universities    2022, 28 (4): 484-492.   DOI: 10.16108/j.issn1006-7493.2020114
    Abstract731)      PDF (1097KB)(458)       Save
    Oxygen fugacity ( f O 2), a quantitative factor in rendering the redox state of a given system, is a key thermodynamic parameter in Earth sciences. The oxygen fugacity of the early Earth and its variation with time, which is a prime goal of Earth sciences, plays important roles in understanding the origin and evolution of the atmosphere, hydrosphere, biosphere and even the whole Earth. Zircon provides the oldest samples yet found on the planet, and is almost the only survivor of the Hadean period. Studies in recent years have demonstrated that the Ce content of zircon is able to record the prevailing f O 2 of its parent magma, leading to the so-called Ce-in-zircon oxybarometer. This provides a unique probe into the redox state of the early Earth. We provide a brief introduction of this technique, and then outline the recent advances on the redox state of the early crust and mantle, followed by a discussion on the f O2 evolution of the early atmosphere, crust and upper mantle and the coupling relation of  f O 2 between them.
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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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    Practice and Thoughts on Enhanced Blended Learning Based on Knowledge Graph
    SHI Yukun, XU Shuyi, DONG Shaochun
    Geological Journal of China Universities    2022, 28 (3): 387-393.   DOI: 10.16108/j.issn1006-7493.2021085
    Abstract874)      PDF (2385KB)(407)       Save
    With the rapid development of the internet and information technology, online and offline blended learning has been widely used. Blended learning is a student-centered strategy that focuses on learners’ abilities of self-regulated learning, collaborative learning and personalized learning and has become a creative learning model for higher education. However, the ability to process, sort, and integrate knowledge that students currently demonstrate under such model is obviously far from sufficient, so is their skill to establish a complete knowledge system. As a result, more guidance from the instructors is urgently needed. The current paper analyzes the advantages and disadvantages of blended learning and introduces the concept of knowledge graph in the field of artificial intelligence as a new element to strengthen the self-regulated learning of students, thereby constructing an enhanced blended learning pedagogy based on knowledge graph. This pedagogy was put into practice in the course of Invertebrate Paleontology at Nanjing University in 2020, which has further demonstrated its potential in improving students’ ability of self-regulated learning.
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    Late Mesozoic Bansin and Range Framework and the Related Tectono-Magmatism of Southeast China
    DONG Changchun, SHU Limin, SHU Liangshu
    Geological Journal of China Universities    2023, 29 (2): 223-239.   DOI: 10.16108/j.issn1006-7493.2021053
    Abstract1378)      PDF (2209KB)(401)       Save
    The Southeast China Block was located in the back margin of the Late Mesozoic Japan-Taiwan volcanic arc. The middle Jurassic-late Cretaceous extensional basins and volcanic-intrusive rock series are widely developed in the Southeast China region as a response of ancient Pacific Plate subduction toward the eastern Asia Continent leading the back-arc expansion. The types of basin include the middle Jurassic rifts, the late Jurassic-early Cretaceous volcanoclastic and lava faulted-depression basins and the late Cretaceous-Paleogene redbed faulted-depression basins. The igneous rock series consists mainly of granitoids, bimodal magmatic rocks, A-type granites, metamorphic core complexes and doming-shape plutons, which were formed in the early Cretaceous with a peak value of 140-110 Ma). The basins coexist together with coeval plutons and constituted the Early Cretaceous Southeast China Basin and Range tectonics. This study summarized the principal geological features of the Late Mesozoic Southeast China basin and range geomorphology and analyzed the petrological and geological structural marks and the constraint factors forming the Southeast China bansin and range framework. Finally we discussed the Late Mesozoic geodynamic process of the Southeast China region.
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    Thermal Structure of the Continental Lithospheric in Southeast China and Its Tectonic Implications
    YANG Peng, LIU Shaowen
    Geological Journal of China Universities    2022, 28 (5): 698-708.   DOI: 10.16108/j.issn1006-7493.2022045
    Abstract396)      PDF (2225KB)(391)       Save
    Southeast China is tectonically characterized by complex geological evolution and intensive Mesozoic-Cenozoic intracontinental deformation. The thermal structure of the continental lithosphere in SE China and its influence on tectonics still remain open. Here we combine the latest heat flow data with the Crust 1.0 model to construct the lithospheric thermal structure for the Yangtze Craton, Cathaysia Block and South China Sea, using the steady-state heat conduction equation, and constrained by independent xenolith and seismological observations. The results show that the thermal structure is of strong heterogeneity in SE China. Most regions are indicative of a ‘hot crust and hot mantle’ thermal structure, except for the Upper Yangtze Region (e.g. Sichuan Basin), where the type of ‘warm crust and warm mantle’ exists. The deep temperatures in the Cathaysia Block and South China Sea are significantly higher than those of the Yangtze Craton at the same depth. The thermal lithosphere thins gradually southeastward from ~200 km in the craton interior to ~110 km in the Cathaysia Block and then to ~70 km in the South China Sea. In addition, the distribution of intracontinental earthquakes is found to be closely related to temperature, i.e. seismicity mainly occurs within the 600 ℃ isotherm. In general, the central-western Yangtze Craton is of cold and thick lithosphere, while the Cathaysia Block and the northern South China Sea is of hot and thin lithosphere, as the results of the Paleo-Pacific plate flat subduction and Cenozoic magmatism in the continental margin. The inherited thermal weakening facilitated the rifting of the SE China continent margin and the subsequent opening of the South China Sea. 

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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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    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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    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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    Discussion on the Practice Teaching of General Geological in Geological Engineering Specialty
    XU Baotian, ZHANG Yong, WANG Bo, YANG Aihua, XIE Guoai
    Geological Journal of China Universities    2022, 28 (3): 382-386.   DOI: 10.16108/j.issn1006-7493.2021090
    Abstract529)      PDF (2366KB)(367)       Save
    In view of the importance of general geology in geological engineering specialty, the theory and knowledge of geological  engineering should be added into the practice teaching of general geology. The knowledge of general geology and disciplines  of engineering are intersected and integrated. The added contents should include three aspects, such as the basic geological  characteristics of rocks, mechanical problems, and specific engineering geological problems. Geological knowledge, geological  thought and philosophy might expand the students’ vision, so that students can integrate the human engineering activities into  the evolution and development of nature on the basis of engineering thought. At the same time, it will achieve the innovation of  practice mode, content reform, promotion and development of students’ learning consciousness and autonomous learning, and  enhance professional thinking. Rock composition is closely related to rock mechanical properties, weathering characteristics and water softening. The roughness, undulation and filling composition of the joint surface affect the shear resistance and water permeability of the joint surface. The landslide problem is a typical rock mass shear failure, and its mechanical mechanism is the same as that of shear joints. The explanation of connecting the two knowledge points enriches the content of practice. This paper indicates that the phenomena observed in the general practice is closely related to many knowledge points in the professional curriculum of geological engineering. It is completely feasible to integrate the above professional knowledge of geological engineering into the practice teaching of basic geology. If the teaching method of increasing the practical teaching link combined with geological engineering specialty is adopted, it not only expands students’ width of knowledge and initially improves students’ professional quality, but also takes an important first step towards the goal of becoming qualified engineers and scientific  researchers in professional fields after graduation.
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    Analysis of Monitoring Technologies of Offshore CO 2 Geological Storage in Japan’s Tomakomai and Its Enlightenment
    XU Xiaoyi, LI Qi, TAN Yongsheng, LIU Guizhen, LI Xiaying
    Geological Journal of China Universities    2023, 29 (1): 13-24.   DOI: 10.16108/j.issn1006-7493.2022096
    Abstract1752)      PDF (3566KB)(364)       Save
    Offshore carbon dioxide (CO 2) capture and storage (CCS) is one of key technologies to cope with global climate change and reduce greenhouse gases such as CO 2, and also an important solution to achieve carbon neutrality goal of China. Offshore sedimentary basins of China have huge storage potential, and the first offshore CO 2 geological storage demonstration project has been officially launched in the Pearl River Mouth Basin of the South China Sea in 2022. Japan’s Tomakomai CCS project is the most successful offshore CO 2 geological storage project in Asia so far, and its monitoring work provides important practical references and technical experiences for the development of China offshore CCS projects. Based on this consideration, this paper comprehensively reviews the case of Tomakomai CCS project, analyzes its implementation, site monitoring items and distribution, monitoring facilities and technologies, monitoring results, etc., summarizes the successful experience of the Tomakomai CCS project and the multi-level and all-round monitoring system of land-wellbore-marine integration, aiming to help offshore CCS projects of China run smoothly, and to ensure the security and safety of the marine ecological environment.
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    Analysis of CO 2 Geological Storage Condition in Jiangsu Province and Offshore Area
    ZHU Qianlin, CHEN Dongbao, GONG Yijie, CHEN Fu, SANG Shuxun, LIU Shiqi
    Geological Journal of China Universities    2023, 29 (1): 25-36.   DOI: 10.16108/j.issn1006-7493.2022080
    Abstract1337)      PDF (7423KB)(364)       Save
    The analysis of the geological condition in Jiangsu Province and offshore area shows that the Subei-Southern South Yellow Sea basin developed in the Lower Yangtze block is a potential site for CO 2 geological storage in Jiangsu Province. The suitable formation for CO 2 storage lithology is analyzed according to the stratigraphic and lithological data. On this basis, according to the drilling and seismic survey profile data, the suitability of CO 2 storage space is discussed through the thickness of CO 2 storage suitable stratum in 800-3500 m depth range of each tectonic unit. The results show that the sandstone layers in lower Yancheng formation, Sanduo formation, Dainan formation, the first and third members of Funing formation, and Chishan formation have good CO 2 storage space. The Chishan formation is less distributed in the basin, and the Yancheng formation, Sanduo formation, Dainan formation and Funing formation are widely distributed. Jinhu depression, Gaoyou depression, Qintong depression, Hai’an depression, Baiju depression, Funing depression, Yancheng depression, Naner depression, Nansi depression, Nanwu depression, Nanqi depression and the Naner low uplift have good CO 2 storage potential. The CO 2 storage potential of Hongze Sag, Linze Sag, Liannan Sag, Lianbei Sag, Nansan Sag and Nanliu Sag is relatively poor.
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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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