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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 Abstract （3896）      PDF（pc） （2292KB）（1269）       Knowledge map    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. Related Articles | Metrics | Comments（0）

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Genesis Process of the Cretaceous Daqushan Pluton in Zhejiang Province: Crystal-Melt Separation and Magmatic Recharge HE Chen, XIA Yan, XU Xisheng, QIU Jiansheng, XU Hang, ZHANG Zhi, ZHAO Sidi Geological Journal of China Universities    2023, 29 (5): 657-678.   DOI: 10.16108/j.issn1006-7493.2022018 Abstract （3444）      PDF（pc） （11167KB）（1304）       Knowledge map    Save The models of trans-crustal magmatic system and crystal mush provide new insights into the study of Cretaceous magmatism in northeast China. The Daqushan pluton is located in the northeast of coastal Zhejiang and Fujian. It is mainly composed of K-feldspar granite with abundant melanocratic microgranular enclaves (MME) and is locally traversed by several mafic-intermediate dikes. A small outcrop of monzonite is exposed near the Chaotoumen. MME have a fine-grained texture with acicular apatites. Zircon U-Pb dating results show that the rock samples in the Daqushan pluton (including the K-feldspar granite, MME, monzonite, and mafic-intermediate dikes) crystallized at ~100 Ma. The K-feldspar granite are highly silicic (SiO2=68.45%-73.82%). While the miarolitic granite (DQS-7) without MME has the higher silica (76.27%), and its whole-rock geochemical and Sr-Nd isotope compositions are similar to those of coeval high silica granites (SiO2>75%) exposed around the Daqushan pluton. Daqushan K-feldspar granite bearing aggregates of plagioclase and K-feldspar exhibit“complementary”trace element geochemical characteristics with Daqushan miarolite and surrounding high silica granites. Further researches show that the Daqushan K-feldspar granite and miarolite were formed by felsic magma which originated from the partial melting of the ancient crustal basement and was recharged by mantle-derived magma. Such felsic magma underwent fractional crystallization and the extraction of high silica melt. Then, the residual silicic cumulate of the crystal mush and high silica melt crystallized and formed the Daqushan K-feldspar granite, miarolite and the surrounding coeval high silica granites. The mafic dikes of Daqushan are enriched in LILEs and depleted in HFSEs and are derived from the partial melting of the enriched mantle metasomatized by subducted dehydration fluids. The results of EPMA analyses indicate that the plagioclase in the K-feldspar granite and MME has a core-mantle-rim texture with low- An in the core (27-36, 25-41) and rim (17-32, 18-26) and relatively high-An in the mantle (28-57, 27-65). Integration of the element geochemical characteristics and Sr-Nd-Hf isotopic results, monzonite and intermediate dikes should be the product of magma mixing of mantle-derived mafic magma and felsic magma, while MME are the product of magma mingling of the two endmembers. The results of the Al-in-hornblende geobarometer show that the crystallization depth of MME is 1.8- 3.0 km, hornblende in monzonite develops core-mantle-rim texture, the crystallization depth of hornblende core and mantle is 17.0-21.2 km, and the depth of hornblende rim is 1.9-4.5 km. Based on the study of the origin and genetic relationships of K-feldspar granite, MME, miarolite, monzonite and mafic-intermediate dikes, and compared with the surrounding coeval high silica granites, this study establishes a model of trans-crustal magmatic systems for Daqushan pluton. The rollback of the subducting paleo-Pacific plate, the back-arc extension in the coastal area and the upwelling of the asthenosphere led to the underplating of the mantle-derived mafic magma, and further induced the partial melting of basement rocks in the lower crust to produce felsic magma. The continuous recharge and heating of mantle-derived magma favor the existence of long-lived melt-bearing regions in magma chambers, promoting magma differentiation and crystal-melt separation and thus forming two magma chambers with depths of 17-21 km and 2-3 km, respectively. K-feldspar granite, high silica granites, monzonite, MME and intermediate-mafic dikes were formed by magma mingling/mixing and crystal-melt separation in two connected magma chambers at different depths. Related Articles | Metrics | Comments（0）

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Evalution of Water in Lunar Interior and Water Ice on Lunar Surface WU Yanwei, HE Jiafeng, WANG Guoguang Geological Journal of China Universities    2024, 30 (02): 165-177.   DOI: 10.16108/j.issn1006-7493.2023013 Abstract （2723）      PDF（pc） （2755KB）（2096）       Knowledge map    Save In the process of lunar exploration, water, as the source of life and an important propellant material for future interstellar travel, is one of the most concerned resources. Since United States Apollo and Soviet Union Lunar projects, the paradigm of “no water” on the Moon has been widely accepted for a long time. In this paper, the research progress on lunar interior water and surface water, the origin of lunar water, the evaluation of water resources, and the methods of exploitation and utilization are systematically reviewed. In recent years, the exploration of water resources on the lunar surface and the in-depth study of water content in lunar samples have revealed that the Moon may contain more water than that previously believed. Not only the interior of the Moon contains relatively abundant water, there are also considerable water resources in the polar region of the Moon. The origin of water on the Moon mainly includes original water that was not degassed during formation and differentiation of the Moon, water from asteroids and comets, and water from solar wind hydrogen implantation. It is estimated that the amount of water ice on the lunar surface is about 14.28 billion tons, and the amount of water caused by solar wind implantation on the lunar surface is about 340,000 tons, which will provide important resources for the construction of lunar bases and deep space exploration in the future. At present, a variety of development and utilization schemes have been proposed for the utilization of lunar water resources, including Thermal Mining of Water Ice on the Moon, Lunar Polar Propellant Mining Outpost (LPMO), The Combined System for Drilling and Extracting Lunar Water Ice and so on. Related Articles | Metrics | Comments（0）

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Exploration of New Methods in Marine Strontium Isotope Stratigraphy CAI Yue Geological Journal of China Universities    2024, 30 (03): 253-268.   DOI: 10.16108/j.issn1006-7493.2024015 Abstract （2723）      PDF（pc） （2031KB）（1495）       Knowledge map    Save Strontium Isotope Stratigraphy (SIS) is an important tool for establishing age models for oceanic sedimentary deposits. It has wide applications in many fields including oil and gas exploration and paleoclimate reconstructions. SIS is based on the premise that global seawater is homogeneous relative to Sr isotopes but with variations through time. A key assumption of SIS is that the samples retain the Sr isotope composition of the original seawater where they form. However, diagenesis and loosely attached impurities can alter the Sr isotope composition of the fossil samples, thereby undermining the meaningfulness of the SIS age. Therefore, sample selection and preparation are crucial for obtaining meaningful SIS ages. This article evaluates existing methods for SIS, including sample preparation and Sr isotope analysis. In recent years, to precisely extract the composition of ancient seawater, studies using Nd, Pb, and Li isotopes in carbonates have thoroughly investigated different methods of sample preparation. Based on these technical advances, this paper thoroughly investigated an oyster sample with independent age constraints from the Miocene shallow-marine deposits of the Gulf of Suez, Egypt. By comparing the elemental composition of sequential leachates of the oyster with those of present-day organisms, this paper proposes a new protocol for SIS sample preparation. This paper also compiles and compares the accuracy and precision of Sr isotope data measured using Thermo-ionizing mass spectrometry (TIMS) vs. Multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). While for samples with abundant Sr, the new generation of MC-ICP-MS can reach similar precision and accuracy as the old generation TIMS, for smaller samples and samples that require higher precision, the new generation TIMS is still the best choice for SIS research. Finally, this paper makes some suggestions for Sr analysis on the MC-ICP-MS.  Related Articles | Metrics | Comments（0）

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Niobium Mineralization in the Miaoya Alkaline Complex, Hubei Province: Constraints from Rutile Mineralogy and Geochronology YING Yuancan, CHEN Wei, LIU Jiajun, YANG Fan, JIANG Shaoyong Geological Journal of China Universities    2024, 30 (03): 345-361.   DOI: 10.16108/j.issn1006-7493.2024019 Abstract （2639）      PDF（pc） （6817KB）（1208）       Knowledge map    Save The Miaoya alkaline complex is mainly composed of syenite and carbonatite enriched in Nb and REE, with a verified Nb2O5 reserve of 0.93 Mt @ 0.12%. It is the second largest carbonatite-hosted Nb-REE deposit in China, second only to Bayan Obo. Previous studies have focused on the genesis of carbonatite and the process of REE enrichment, but the occurrence and enrichment mechanism of Nb in syenite are still unclear. Based on field geological surveys, detailed petrography, mineral chemistry, and U-Pb dating of the Nb-bearing minerals in syenite were obtained using TIMA, EMPA and LA-ICP-MS analyses. The results show that the main Nb-bearing mineral in the Miaoya syenite is rutile, which can be divided into magmatic and hydrothermal generations based on texture and chemical composition. Magmatic rutile is rare, while hydrothermal rutile is common in various syenites, mostly disseminated along the edges or fissures of primary rutile or closely associated with biotite and ilmenite. Magmatic rutile shows low contents of Nb2O5 (1.43%~2.56%), FeO (0.74%~1.01%), and other trace elements (e.g., Ta, Cr, V, W, Mo, Sb); while hydrothermal rutile has variable enrichments of Nb2O5 (3.48%~20.68%), FeO (1.18%~6.92%), and other trace elements. In-situ U-Pb dating of rutile illustrates that the formation age of magmatic rutile is 446±21 Ma, while the formation age of hydrothermal rutile is 240±19 Ma, indicating that Nb mineralization in syenite experienced initial enrichment during the early Paleozoic magmatic stage and secondary enrichment during the Triassic hydrothermal metasomatic stage. In summary, we believe that Nb enrichment and mineralization in the Miaoyao complex are controlled by both magmatic and hydrothermal processes. During the early Paleozoic magmatic stage, niobium within syenite is mainly hosted by rutile, biotite and Ti-bearing minerals (e.g., ilmenite); in the Triassic hydrothermal metasomatic stage, hydrothermal fluids can decompose biotite to form secondary Nb-rich rutile and columbite, or metasomatize primary rutile and ilmenite to generate hydrothermal Nb-rich rutile.  Related Articles | Metrics | Comments（0）

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Grain-size Characteristics and Environmental Implication of Neogene Red Clays in the Chinese Loess Plateau LU Keke, CHEN Zhong, YANG Yanpeng, ZHANG Jialin, ZHAO Zhongqiang, XIA Dinghong, NI Chunzhong, SONG Yinxian, ZHANG Shitao Geological Journal of China Universities    2023, 29 (5): 713-725.   DOI: 10.16108/j.issn1006-7493.2022020 Abstract （2564）      PDF（pc） （1237KB）（2651）       Knowledge map    Save The aeolian origin of red clays in the Loess Plateau has been unanimously recognized. The earliest red clay was found in the late Oligocene and early Miocene, indicating that the arid environment had been formed in the inland northwest of China at the end of Paleogene. The grain size characteristics of red clay in the loess plateau show that the average grain size gradually decreases from the north to the south, indicatin g that the initial monsoon system has been established, and the winter wind played an important role in the transport of aeolian dust. The grain size distribution of red clay indiactes that it is composed of two components. The coarse grain (>20 μm) represents those transported by the near surface wind (winter wind), while the fine grain (<5 μm) represents those transported by the upper westerly wind. The grain size composition characteristics of red clays well record the development and change of atmospheric circulation. Since the end of Oligocene, the average grain size and sedimentation rate of red clays in the west of Liupanshan Mountain increased at 21.3-20.2 Ma, 16.0-13.3 Ma and 8.7-6.9 Ma, which may be related to global cooling and the Qinghai-Tibet Plateau uplift, and the 8.7- 6.9 Ma increase was mainly controlled by global cooling. In the red clay section to the east of Liupanshan, the grain size of variation characteristics shows that the grains deposited during 7.6 Ma to 6.2 Ma or to 5.4 Ma is coarse, indicating that the winter monsoon was strong. After that, the average particle size was fine up to 3.6 Ma, and the deposition rate was low, indicating that the winter monsoon was weak climate environment. From 3.6 Ma to 2.6 Ma, most profiles show an increase in mean grain size, an increase in sedimentation rates, and an increase in both winter and summer monsoon, which indicates to the transition to Quaternary glacial period. The development of the Arctic ice sheet and the uplift of the Qinghai-Tibet Plateau may have contributed to these changes. Related Articles | Metrics | Comments（0）

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Macroscopic and Mesoscopic Investigation on the Physical and Mechanical Characteristics of Coral Limestone at Different Depths MA Linjian, LIU Huachao, ZHANG Wei, LI Qi, ZHU Honghu, WU Jiawen Geological Journal of China Universities    2023, 29 (3): 471-478.   DOI: 10.16108/j.issn1006-7493.2021074 Abstract （2466）      PDF（pc） （2519KB）（3242）       Knowledge map    Save In order to investigate the physical and mechanical characteristics of coral reefs with different depth in the South China Sea, scanning electron microscopy (SEM) and X-ray tomography (CT) technology are used to characterize the micro morphology and internal pore structure characteristics of shallow and deep reef limestone. Quantitative relationships between P-wave velocity and porosity as well as density were established. Uniaxial compression tests on dry and saturated reef limestone were also carried out. Results show that shallow reef limestone is porous with excellent pore connectivity, and the main mineral composition is aragonite, which belongs to the biological sedimentary rock. While deep reef limestone is dense with poor pore connectivity, and the main mineral composition is calcite, belonging to the metamorphic rock. The porosity of deep reef limestone is about 1/10, with an average peak compressive strength of about 4.8 times and an average elastic modulus of about 4.5 times that of shallow reef limestone. Reef limestone belongs to soft or extremely soft rock, characterized by brittle destruction property. The typical damage pattern is multiple rupture surface destruction along the primary pore, growing line of corals and weak bond surface, with high  residual strength. The hydrogenic effect of reef limestone is significant, and the water rationality of deep reef limestone is stronger than shallow reef limestone. The significant difference of physical and mechanical performances in shallow and deep reef limestone are mainly due to the variety in mineral components, pore structure and lithology caused by the varying degree of rock cementation with different depths. Related Articles | Metrics | Comments（0）

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Trace Element Characteristics and Geological Significance of Sphalerite in Xiwan Lead-Zinc Deposit, Luzong Basin, Anhui Province ZHANG Hongqiu, HAN Shanchu, ZHANG Yong, PAN Jiayong, ZHANG Yanqun, ZHAO Bibo, DING Yong, JIANG Yao, HU Shengping Geological Journal of China Universities    2023, 29 (5): 693-704.   DOI: 10.16108/j.issn1006-7493.2022028 Abstract （2459）      PDF（pc） （2751KB）（1626）       Knowledge map    Save The Luzong volcanic basin is an important part of the metallogenic belt in the middle and lower reaches of the Yangtze River. In recent years, a large-scale Xiwan lead-zinc deposit has been discovered in the East Ma’anshan Formation on its northern margin. Previous studies have shown that sphalerite in this deposit is enriched in certain dispersed elements, but there are few in-depth studies on its content and distribution characteristics and comprehensive evaluation of dispersed elements is lacking. Therefore, in this paper, the LA-ICP-MS analytical method was used to study the characteristics of trace elements in sphalerite of No. Ⅳ and Ⅴ ore bodies in the Xiwan lead-zinc deposit and discuss its geological significance. The results show that (1) Sphalerite is rich in Fe, Mn, Cd, Pb elements, and depleted in In, Tl, Se, Te, Sn elements, among which dispersed Cd element has certain comprehensive utilization values; (2) The substitution mechanisms of trace elements in sphalerite mainly include single element and multi-element coupling. Among them, the substitution mechanism of single element mainly includes Fe2+ instead of Zn2+, Cd2+ instead of Zn2+, etc. The multi-element coupling substitution mechanism mainly includes (Cu++Ge3+) instead of 2Zn2+, (2Cu++Ge4+) instead of 3Zn2+, etc.; (3) The composition characteristics of Fe, Mn, Cd, In and other trace elements (dispersed elements) in sphalerite show that the metallogenic temperature of the Xiwan lead -zinc deposit is medium to low temperatures, which belong to the epithermal deposit.  Related Articles | Metrics | Comments（0）

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Precipitation-induced Pressure Wave Propagation in Unsaturated Zone and Its Effect on Rapid Groundwater Discharge DANG Lei, XIE Yueqing, WANG Chuan, CHANG Yang, ZENG Xiankui, WU Jichun Geological Journal of China Universities    2023, 29 (4): 580-589.   DOI: 10.16108/j.issn1006- 7493.2021104 Abstract （2408）      PDF（pc） （1977KB）（813）       Knowledge map    Save A large number of studies, using water chemistry and stable isotopes to conduct hydrograph separation, indicate that majority of stream water during rainfall is derived from ‘old water’ that is stored in the catchment before the rainfall. This phenomenon is known as ‘old water paradox’. Pressure wave in unsaturated zone driven by precipitation is regarded as a potential underlying mechanism. In this study, we established four numerical soil column experiments with different soil types (sand, loamy sand, sandy loam and loam). We attempted to explore pressure wave propagation and the possibility of rapid groundwater discharge driven by the pressure wave with demonstrative experiments. Our results show that after the first intensive rainfall, pressure wave were generated in the four columns and were observed at the bottom after 1.86, 2.84, 5.24 and 7.46 days. In comparison, the relevant soil water arrived at the bottom after 6.12, 10.33, 18.05 and 30.00 days. The differences between celerities and velocities are 74.71, 51.05, 27.08 and 20.13 cm/d. Our study indicates that celerities and velocities are strongly affected by soil hydraulic conductivities and soil retention curves, and pressure waves in sand can be propagated more easily than those in other soil types. As the thickness of unsaturated zone is usually linearly proportional to the distance from river bank, pressure wave generated during precipitation can propagate into groundwater and drive rapid groundwater discharge. This process would be easier in more permeable soils. Overall, this study advances our understanding of catchment hydrology and helps discover underlying mechanisms in a theoretical manner.  Related Articles | Metrics | Comments（0）

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Reactive Transport Numerical Modeling for Deep Geological Sequestration of Brine Wastewater DU Zhuoran, DU Song, YANG Yun, SONG Jian, WU Jianfeng, WU Jichun Geological Journal of China Universities    2023, 29 (4): 571-579.   DOI: 10.16108/j.issn1006-7493.2021110 Abstract （2348）      PDF（pc） （2212KB）（1542）       Knowledge map    Save Brine wastewater deep well injection in China is still at the stage of access demonstration. The transport of liquid waste in deep reservoirs involves variable density drive, water-rock chemical reactions and variable-parameter synergistic physical-chemical interactions. How to quantitatively characterize these processes is one of the key scientific and technological challenges to be solved in deep well injection. Consequently, this paper selected a certain injection zone in Ordos Basin as prototype, used PFLOTRAN to construct a variable-density and variable-parameter reactive solute transport model to predict and evaluate the migration, transformation and evolution of reservoir minerals, as well as the change of reservoir properties after the brine wastewater injection to the deep geological body. As the simulation results showed, the injection of brine wastewater into the injection zone contributes to secondary minerals precipitation, such as anhydrite, calcite and fluorite; the geological storage capacity decreases by 1.51% approximately in the simulated 100 years; and the contamination area is around 2.57 km2. This model provides a simulation tool to quantitatively characterize the migration and transformation process of brine wastewater components after the deep well injection. Related Articles | Metrics | Comments（0）

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Degradation of Trichloroethylene in Activated Sodium Persulfate System HAO Tian, ZHANG Yun Geological Journal of China Universities    2023, 29 (4): 600-607.   DOI: 10.16108/j.issn1006-7493.2021076 Abstract （2336）      PDF（pc） （1110KB）（769）       Knowledge map    Save Trichloroethylene (TCE) was taken as a target pollutant to study its degradation characteristics in the environmentally friendly chelating agents, sodium citrate (TCD) and citric acid (CA), chelating ferrous ion (Fe2+)-catalyzed sodium persulfate (Na2S2O8) system. The effects of the proportion of sodium persulfate, chelating agents, and pH value on the degradation of TCE were investigated, and the optimal proportion of all components and suitable pH value were obtained. Both TCD and CA had effectively chelated Fe2+-catalyzed sodium persulfate, which degraded TCE in water, and the degradation of TCE abided by the first-order kinetic reaction model. The optimal proportion in mole was 20:10:10:1 for Na2S2O8/TCD/Fe2+/TCE and 20:5:10:1 for  Na2S2O8/CA/Fe2+/TCE, respectively, at which both the degradation rate and the first-order reactive rate constant reached their maximum values. The maximal degradation rate was 96.7% and 97.6% and the maximal reactive rate constant was 2.48×10-2 and 2.68×10-2 min-1 for the two reactive systems, respectively. Additionally, the usage of CA for the optimal proportion was only half of TCD. For small proportion, both degradation rate of TCE and the first-order reaction rate constant increased with the increasing amount of TCE, CA, or Na2S2O8. However, excessive chelating agents could form an over-stabilized chelate with Fe2+, which reduced the catalytic effect of Fe2+ and the oxidative capacity of Na2S2O8. Excessive amount of Na2S2O8 could generate much more sulfate radicals, and these sulfate radicals could consume internally, refraining the degradation reaction of TCE. In the system of Na2S2O8/ Fe2+/TCE being 20:10:1, the catalytic effect would dwindle if the proportion in mole was greater than 10 for TCD and 5 for CA. In the system of TCD/Fe2+/TCE being10:10:1or CA/Fe2+/TCE being 5:10:1, the reaction would be refrained if the proportion in mole was greater than 20 for Na2S2O8. A suitable range of pH value was necessary for the degradation of TCE in activated sodium persulfate system. Alkaline condition refrained the degradation reaction of TCE, while acid to neutral condition was helpful for the reaction. Related Articles | Metrics | Comments（0）

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The Petrogenesis of Baishuizhai Granitic Pluton and Its Significance to Uranium Mineralization in the Xiazhuang Area, Guangdong Province LI Kun, CHEN Weifeng, GAO Shuang, SHEN Weizhou, HUANG Guolong, LIU Wenquan, FU Shuncheng, LING Hongfei Geological Journal of China Universities    2023, 29 (4): 497-513.   DOI: 10.16108/j.issn1006-7493.2021117 Abstract （2280）      PDF（pc） （2375KB）（2268）       Knowledge map    Save The Baishuizhai pluton is one of the main ore-bearing wall rocks of the Zutongjian uranium deposit in the northwestern part of the Xiazhuang granite-related uranium ore filed, yet its petrogenetic mechanisms and its relationship with uranium mineralization are still unclear. Thus, in this study, we present zircon SHRIMP U-Pb ages, whole-rocks and mineral geochemical data for the Baishuizhai granite. Field and petrographic investigations show that the Baishuizhai granitic pluton was emplaced into the Xiazhuang granitic batholith, mainly composed of fine-grained two-mica granite and muscovite granite, and the zircon SHRIMP U-Pb dating reveals that both granites were formed during the Indochina period with ages of 229.4 Ma and 231.8 Ma, respectively. They show typical peraluminous S-type granitic geochemical characteristics that are high SiO2 contents, total alkalis contents and ACNK values ( ≥ 1.1), low FeOt+MgO+TiO2 contents and P2O5 contents, enriched in Rb, Th and U, depleted in Ba, Sr, P and Ti, and enriched in aluminum-rich minerals. Compared with the Xiazhuang granite, both types of granites in the Baishuizhai pluton show enriched in inherited zircon, higher SiO2 contents and Rb/Sr ratios, but lower FeOt+MgO+TiO2 contents, P2O5 contents, Zr/Hf ratios, and Fe2+/(Fe2++Mg) ratios of biotites, indicating that they were derived from low partial melting of reducing material-rich feldspathic meta-pelites, and are not formed by the differentiation evolution of the parent magma of the mafic meta-pelites-derived Xiazhuang granite. Furthermore, compared with the two-mica granite, the muscovite granite display significant tetrad REE patterns, lower REE, Zr/Hf ratios and Eu/Eu* values, indicating that an interaction of F-rich fluids with the magma occurred in the formation of the muscovite granite. Both types of granites in the Baishuizhai granitic pluton are enriched in uranium and can be important uranium-bearing granites in the region. Relative to the 2-mica granite in the Baishuizhai pluton, the muscovite granite is more enriched in uranium and more favorable to be uranium source rocks for hydrothermal uranium mineralization. Related Articles | Metrics | Comments（0）

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One-stop Sharing and Service System for Geoscience Knowledge Graph ZHU Yunqiang, DAI Xiaoliang, YANG Jie, WANG Shu, SUN Kai, QIU Qinjun, LI Weirong, QI Yanmin, HU Lei, LYU Hairong, WANG Xinbing, ZHOU Chenghu Geological Journal of China Universities    2023, 29 (3): 325-336.   DOI: 10.16108/j.issn1006-7493.2023029 Abstract （2208）      PDF（pc） （7167KB）（3095）       Knowledge map    Save As the most effective way of knowledge organization and service at present, knowledge graph has become the cornerstone of artificial intelligence and has been widely used in semantic search, machine translation, information recommendation and so on. In the era of big data, there is an urgent need of Geoscience knowledge graphs for integrating, mining and analysis of scattered, multi-source and heterogeneous Geo-data and its unknown knowledge intelligent discovery. To promote the construction and application of Geoscience knowledge graphs, the Deep-time Digital Earth (DDE) International Big Science Program has taken knowledge graph as its one of the core research contents since its launch in 2019. After more than three years of construction, DDE has built a large number of Geoscience knowledge graphs, and it strong needs one-stop sharing and service system of these knowledge graphs. Firstly, this paper introduces the content framework, composition as well as characteristics of the DDE knowledge graphs. On this basis, the design of the one-stop sharing and service system for the Geoscience knowledge graph is designed that include the design of the system functional and technical architecture. Finally, the development and operation environment & tools, and key technologies of the system are discussed in detail. The practice has proved that the system can effectively realize the one-stop sharing and open access of DDE knowledge graphs. Meanwhile, it sets an example for other fields or domains’ knowledge graph integrating and sharing systems. Related Articles | Metrics | Comments（0）

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The Generation of Acid Mine Drainage: Insights from Reactive Transport Modeling and Stable Isotope QIU Wenjie, DU Zhuoran, YIN Ziyue, SUN Yuanyuan, ZHU Xiaobin, WU Jianfeng Geological Journal of China Universities    2025, 31 (01): 1-13.   DOI: 10.16108/j.issn1006-7493.2024091 Abstract （2187）      PDF（pc） （2327KB）（1615）       Knowledge map    Save Acid mine drainage (AMD) resulting from mining activities is a global environmental issue. Investigating the acid generation mechanisms of AMD and the biogeochemical processes affecting the release, migration, and transformation of heavy metals and sulfates provides a scientific basis for quantitatively predicting AMD formation and developing remediation strategies. In this paper, a multiphase reactive transport model for water-gas two-phase flow is constructed based on the TOUGHREACT/EOS3 code to simulate the acid generation process of sulfide minerals (such as pyrite) in tailings impoundment under the influence of atmospheric precipitation and oxygen. It further considers the physical and geochemical reaction processes of associated species in the migration and transformation within the aqueous medium. The reaction network includes the release of H⁺ from the oxidation and dissolution of sulfide minerals, the migration and transformation of iron ions and sulfate, and the pH buffering processes caused by the dissolution and precipitation of major minerals. Finally, by incorporating sulfur stable isotopes into the reactive transport model, the study identifies the bacterial sulfate reduction processes and corresponding sulfur isotope fractionation occurring during the formation of AMD. The model quantitatively assesses the acid production contributions under different oxidation pathways of pyrite, revealing that simultaneously considering the parallel oxidation processes of O₂(aq) and Fe3+ increases the concentrations of acid, iron ions and sulfate. The pH is controlled by the release of H⁺ from pyrite oxidation and the neutralization reactions corresponding to mineral dissolution and precipitation. Stable isotope reactive transport model indicates significant differences in δ34S values under different fractionation kinetic enrichment factor, and using the Rayleigh fractionation model in an open system can greatly overestimate the enrichment factor. This research aids in understanding and predicting the formation and migration processes of acidic water in mining environments, which is crucial for addressing environmental pollution issues caused by mining activities.  Related Articles | Metrics | Comments（0）

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Changes in Oceanic Ba Cycle Driven by the Neoproterozoic Oxygenation Event WEI Wei, SUI Peishan, CHEN Tingting, HUANG Fang Geological Journal of China Universities    2024, 30 (03): 288-296.   DOI: 10.16108/j.issn1006-7493.2024009 Abstract （2168）      PDF（pc） （946KB）（1755）       Knowledge map    Save The late Neoproterozoic witnessed an increase in the atmospheric and oceanic oxygen levels, namely the Neoproterozoic Oxygenation Event (NOE), likely resulting in the naissance and radiation of metazoans and the establishment of complex ecosystem. Oceanic oxygenation could change oceanic chemistry, such as species and valence states of Fe, C, and S, and the biogeochemical cycle of Ba in the ocean is strongly controlled by the S species and sulfate concentration. This review introduces how the NOE changed the oceanic Ba cycle: (1) Before the NOE, the oceanic sulfate concentration was low and the oceanic Ba cycle was conservative; (2) during the NOE, the oceanic sulfate increase led to excess Ba enrichments in sediments and formation of massive barite deposits; and (3) after the NOE, the ocean kept over-saturated relative to barite until the terminal Paleozoic and the Ba cycle was controlled by biological productivity afterwards. In addition, this review suggests to use Ba isotope system to reconstruct the oceanic Ba concentration, and indirectly to estimate the oceanic sulfate concentration (oxygenation extent) during the late Neoproterozoic. Related Articles | Metrics | Comments（0）

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Characteristics of Water Saturation During Drainage and Imbibition Processes in Unsaturated Zones ZHANG Shengshan, WEI Yunbo, GU Xi Geological Journal of China Universities    2023, 29 (6): 934-944.   DOI: 10.16108/j.issn1006-7493.2022048 Abstract （2160）      PDF（pc） （2949KB）（825）       Knowledge map    Save The unsaturated zone, which is the link between the s urface water and groundwater, plays a key role in controlling water exchange and solute transport in the soils. Infiltration in the unsaturated zone is in essence a problem of twophase (air and water) immiscible displacement. A deep understanding of the airwater displacement process in the unsaturated zone is of great significance for the management and sustainable use of groundwater. A s eries of drainageimbibition experiments are carried out to study the watercontent distribution in the unsaturated zone. The light transmission method is used to monitor water content in the 2-dimensional sandbox during the drainageimbibition cycles. It is found that the lateral fluctuation of water content in the drainage process (0.145-0.175) is greater than that in the imbibition process (0.150-0.165) due to the existence of unstable drainage processes at the pore-scale. The difference of water content between drainage and imbibition means that the mechanism happened at pore-scales should also be affected by water movement at darcy-scales. Related Articles | Metrics | Comments（0）

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Mechanism of Vital Effect of Chemical Composition of Foraminifera Calcite Shell SUN Qianyuan, CHEN Tianyu Geological Journal of China Universities    2024, 30 (03): 362-370.   DOI: 10.16108/j.issn1006-7493.2024014 Abstract （2132）      PDF（pc） （1682KB）（944）       Knowledge map    Save The element and isotope compositions of calcite formed by calcification of foraminifera shells are widely used in reconstructing paleo-marine evolution. However, it has been found that the chemical composition of foraminiferal calcite is significantly different from that of inorganic calcite precipitated directly in seawater, indicating that the chemical composition of foraminiferal shell is affected by the “vital effect”. In order to explore the controlling factors behind this “vital effect” and get more reliable paleo-oceanic indicators, a series of studies have been carried out from the aspects of calcification process and element partition mechanism. This study first summarized the two main ways of foraminifera calcification: seawater vacuolization model and Ca2+ transmembrane model. In the enclosed or semi-enclosed calcified space, the composition of trace elements in the fluid produces a Rayleigh fractionation effect with the precipitation of calcium carbonate, which becomes a classical model to explain the mechanism of the “ vital effect” of trace element partition in foraminifera. However, this model is still difficult to explain quantitatively the mechanism of low magnesium in foraminifera calcite shells, the composition of calcium isotopes, and the sensitivity of Mg/Ca ratios to temperature. Bio-carbonates, including foraminiferal calcite, may be common exist metastable precursor carbonate. The partition effect of trace elements during the conversion of metastable precursor carbonates to calcite may be an important reason to the formation of low magnesium in foraminifera. The recent discovery of vaterite in living foraminifera supports this hypothesis, but the partition of trace elements and isotope effects during the conversion of carbonate precursors to calcite are rarely studied. This paper focuses on the partition model of trace elements when the precursor of vaterite in foraminifera transformed to calcite. This model can explain the phenomenon of low magnesium in foraminifera quantitatively. At the same time, combined with the calcium isotope data synthesized in the laboratory and the calcium isotope fractionation mechanism in the calcification process of coccolith, this paper attempts to further conjecture the mechanism of “vital effect” of the chemical composition of foraminifera calcite shells from the perspective of calcium isotope. Metastable precursors may contribute significantly to the “vital effect” of trace elements partition and isotope fractionation during foraminifera calcification, and this model needs to be further verified from the perspective of other trace elements and isotopes.  Related Articles | Metrics | Comments（0）

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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 Abstract （2119）      PDF（pc） （1695KB）（1150）       Knowledge map    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. Related Articles | Metrics | Comments（0）

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Geological Journal of China Universities    2024, 30 (03): 240-.   Abstract （2112）      PDF（pc） （466KB）（248）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Synthesis Technology and Application of Red Mud Based Layered Double Hydroxide JIANG Yimei, SHEN Zhengtao Geological Journal of China Universities    2024, 30 (01): 12-21.   DOI: 10.16108/j.issn1006-7493.2022065 Abstract （2084）      PDF（pc） （1410KB）（1724）       Knowledge map    Save Red mud is a highly alkaline waste produced in the process of refining alumina from bauxite. Due to the rapid development of the aluminum industry, the annual discharge of red mud in the world has seriously exceeded the environmental load, resulting in huge disposal pressure and pollution risks. Therefore, the efficient utilization of red mud as a resource is imminent. The preparation of layered double hydroxide (LDH) from red mud is a circulating route, and has the potential for large-scale industrialization. This paper reviews the research progress of red mud based LDH synthesis technology and application. It is found that the main synthesis processes include co-precipitation, calcination-hydration and mechanochemical methods. The synthesized red mud-based LDH type is affected by bauxite composition and smelting technology. Significant impact. Red mud based LDH is typically used as an absorbent to remove inorganic pollutants and capture CO2, and it is also a new environmentally friendly halogen-free flame retardant additive. Red mud based LDH is also an excellent photocatalyst, and the introduction of impurities(Fe2O3) in red mud leads to the local construction of heterostructures, which is beneficial to the separation and transfer of photosensitive electrons and holes. Finally, this paper puts forward the following prospects: (1) In the context of carbon neutral targets, the preparation of red mud based LDH meets the sustainable development goals such as “circular economy” and has practical potential for large-scale application, and the synthesis and application research should be vigorously promoted; (2) It should focus on how to further optimize the synthesis process, improve yield, enhance sustainability (such as introducing other wastes as divalent metal sources), improve synthesis specificity, and reduce the environmental risk of red mud-based LDH in the application process; (3) Understand the relationship between LDH properties and its performance, and exploit the advantages of the heterostructure of red mud based LDH achieve a more efficient a pplication. Related Articles | Metrics | Comments（0）

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Using Vanadium Isotopes to Constrain the Proportion of Lunar-forming Material SHI Zhen, QI Yuhan, HUANG Fang, DING Xin Geological Journal of China Universities    2024, 30 (03): 371-378.   DOI: 10.16108/j.issn1006-7493.2023065 Abstract （2066）      PDF（pc） （1037KB）（1156）       Knowledge map    Save The classic giant impact model is currently the most widely accepted hypothesis for explaining the lunar formation process. It posits a collision between a proto-Earth in its late accretion stage and a Mars-sized impactor named Theia. According to this model, the majority of the Moon’s material is derived from Theia. However, there is still a lack of precise constraints on the contribution percentage of the impactor to the lunar mass. In this study, high-precision measurements of mantle peridotites and komatiites are employed to reevaluate the V isotope composition of the Bulk Silicate Earth (BSE). Unlike previous studies, the new data indicate δ51VBSE=-0.91±0.02‰（2SE, n=18）. We incorporated this into a two-component mixing model for the Earth-Moon system, considering a system with pre-impact (proto-Earth, Theia) and post-impact (Earth, Moon, escaping mass) components. The best estimate for the mass fraction of Theia in the present Moon ranges from 73% for MTheia=0.8MMars to 83% for MTheia=0.45MEarth This represents a reduction of approximately 5% in Theia’s contribution compared to earlier studies. These findings provide more reliable parameters for the classic collision model, contributing to a deeper understanding of the lunar formation process. Related Articles | Metrics | Comments（0）

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Mountain Building and Silicate Weathering: A Review and Perspectives LI Shilei, CHEN Yang, CHEN Jun Geological Journal of China Universities    2024, 30 (03): 336-344.   DOI: 10.16108/j.issn1006-7493.2024024 Abstract （2051）      PDF（pc） （913KB）（2220）       Knowledge map    Save The relationship between mountain uplift and climate change has been a prominent focus of research in recent decades. Since the emergence of the famous “uplift-weathering “ hypothesis in the 1980s, which suggests that tectonic uplift of mountains drives climate change over millions of years through silicate weathering, significant attention has been directed towards this concept. Extensive continental denudation and weathering records have been established to test this hypothesis. Despite the majority of these records aligning with the hypothesis, the presence of alternative interpretations complicates direct hypothesis testing. Consequently, numerous studies have explored contemporary weathering processes to better understand this relationship. However, these studies have unveiled that weathering in mountainous regions is not primarily controlled by physical denudation processes and is unlikely to fluctuate in response to tectonic activities. This challenges the fundamental premise of the “upliftweathering” hypothesis. This paper conducts a comprehensive review and analysis to elucidate the reasons for this contradiction. Moreover, it examines the potential of non-local weathering in floodplains as a novel weathering mechanism to resolve this inconsistency. Additionally, it delves into the opportunities and challenges within the realm of non-local weathering research.  Related Articles | Metrics | Comments（0）

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Reconstructing Humidity Using the Triple Oxygen Isotopes of Pedogenic Carbonates DA Jiawei Geological Journal of China Universities    2024, 30 (03): 241-252.   DOI: 10.16108/j.issn1006-7493.2023069 Abstract （2026）      PDF（pc） （1107KB）（1083）       Knowledge map    Save The secondary carbonate formed during the soil formation process (pedogenic carbonate) is a crucial material in paleoclimate studies. In previous research, it has been widely used to reconstruct atmospheric CO2 concentrations, paleoaltimetry, the evolution of regional paleovegetation (C3, C4 plants), precipitation, and temperature. However, like most other paleoclimate indicators, proxies based on pedogenic carbonate (such as stable carbon and oxygen isotopes, trace elements, etc.) are influenced by multiple climate factors, resulting in ambiguity. Therefore, obtaining reliable paleoenvironmental information requires the integration of multiple indicators. With the recent development of isotope testing methods, in addition to the traditional 18O/16O, triple oxygen isotope analysis (17O/16O) has been increasingly applied in paleoclimatology. Pedogenic carbonates inherit the oxygen isotope signal of soil water. Combined with the carbonate-clumped isotope temperature, the 17O anomaly of soil water can be reconstructed. The soil-water-Δ′17O is mainly controlled by the evaporation process, thus providing information about past humidity. This article provides a detailed introduction to the theoretical basis of pedogenic carbonate triple oxygen isotopes. It quantitatively discusses the impact of various climate factors on pedogenic carbonate triple oxygen isotopes using existing soil water triple oxygen isotope models. Related Articles | Metrics | Comments（0）

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Columbite-group Minerals from the Pegmatite in the Lalong Pluton, Eastern Himalaya and the Two-staged Nb-Ta Mineralization LI Xuejiao Geological Journal of China Universities    2023, 29 (6): 847-861.   DOI: 10.16108/j.issn1006-7493.2022006 Abstract （2020）      PDF（pc） （8863KB）（1593）       Knowledge map    Save Leucogranites are widely distributed in the Himalayan orogenic belt and are closely related to rare-metal mineralization. This study focuses on the Nb and Ta mineralization and columbite-group minerals (CGMs) from the granitic pegmatite in the Lalong pluton, eastern Himalayas. Three zones (i.e., wall zone, intermediate zone, and core zone) can be identified from the Lalong pegmatite based on their lithology. The CGMs mainly exist in the intermediate zone (quartzfeldspar- muscovite zone). Major element, trace element, and U-Pb isotopic compositions of CGMs were systemically analyzed. Two types of CGMs are distinguished by occurrences and chemical compositions. Type I CGMs have euhedral occurence and uniform chemical compositions with low Ta# [Ta/(Nb+Ta)] ranging from 0.08 to 0.34. Type II CGMs mainly distribute around crystals of the type I CGMs or as tiny veins cutting through the type I CGMs with higher Ta# ranging from 0.45 to 0.60. Several structures (i.e., oscillatory structure, metasomatic structure, fissure-filling, and porous) are well developed in the type II CGMs. The normalized REE patterns of these CGMs are similar, showing a strong negative Eu anomaly with δEu ranging from 0.001 to 0.020. The LREE/HREE ratio of CGMs ranges from 0.016 to 0.044. Our results indicate a two-staged Nb-Ta mineralization in the Lalong pluton. The first-staged mineralization is related to the magmatic process with the crystallization of the type I CGMs, while the second-staged process is late-staged hydrothermal fluidrich magmatism with the formation of the type II CGMs. The REE pattern of the type II CGMs, however, is not convincing enough to indicate the magmatic-hydrothermal mineralization. The CGMs U-Pb isotopic analysis reveals the age of Nb- Ta mineralization at 22.3±0.3Ma, implying a rare-metal resource potential of the leucogranites formed in the Neohimalayan period (25-14 Ma). Related Articles | Metrics | Comments（0）

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Sedimentology and Carbon Isotope Records of Latest Early Permian Carbonate Platform Drowning Event in Lower Yangtze Region ZHANG Xiaoji, HU Xiumian, LI Juan, XU Yiwei Geological Journal of China Universities    2024, 30 (04): 379-396.   DOI: 10.16108/j.issn1006-7493.2023030 Abstract （2006）      PDF（pc） （38847KB）（273）       Knowledge map    Save The Lower Yangtze region in South China plate was located near the equator during the Early Permian, where the shallow-water carbonates of the Qixia Fornation widely developed. The latter were subsequently replaced by the black shale and siliceous rocks of the Gufeng Formation, representing a carbonate platform drowning event at the end of Early Permian. In this study, the carbonate microfacies and carbon isotopic stratigraphy of the Qixia and Gufeng formations were systematically studied in the Pingdingshan section of Chaohu, Anhui Province and Zhengpanshan section of Jurong, Jiangsu Province in order to explore the mechanism of this depositional event. Microfacies data shows that the uppermost of the Qixia Formation can be divided into 9 microfacies, belonging to the inner ramp to middle ramp environment. The lowermost of the Gufeng Formation can be divided into 5 lithofacies, indicating a deep-water basin environment. The depositional environment and paleo-water depth at the boundary between the Qixia and Gufeng formations changed obviously, representing the drowning event of the carbonate platform during the Latest Early Permian. At the same place, sudden drop in the content of calcium carbonate, negative carbon isotope excursion and obviously positive carbon isotope of organic excursion indicate the suddenness and eventuality of carbonate platform drowning. The results show that there is a mirror image relationship between δ13Ccarb of carbon isotope and δ13Corg of organic matter. Carbon isotopes of carbonate and organic matter show decoupling changes of negative and positive excursions, respectively, which may be the result of terrigenous organic matter input. We suggest that the drowning of carbonate platform may be caused by relative sea level rise. Related Articles | Metrics | Comments（0）

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Petrogenesis and Tectonic Implications of the Indosinian Fengxian Pluton, Western Qinling Orogeny NI Chunyu, JIANG Yaohui Geological Journal of China Universities    2023, 29 (4): 559-570.   DOI: 10.16108/j.issn1006-7493.2021121 Abstract （2001）      PDF（pc） （1868KB）（889）       Knowledge map    Save This paper reports systematically petrological and SHRIMP zircon U-Pb dating, whole-rock geochemical and Sr-Nd-Hf isotopic research for the Fengxian Pluton. We discussed the magmatic evolution, source characteristics, tectonic and geodynamic settings of these plutons. Our study shows that: 1. The Fengxian pluton is composed of granodiorite and quartz monzonite, invaded in the Middle Triassic (~237.5 Ma). The SiO2 content of the rock is 61.7~66.7 wt %, belonging to the high potassium calc-alkaline series, with relatively high MgO content (1.49-2.43 wt%) and Mg# value (0.53-0.58), belonging to the high-K calc-alkaline series. They are enriched in light rare earth elements (LREE) and lack marked negative Eu anomalies. They are also enriched in LILE and depleted in HFSE. Their high Sr (474×10-6-629×10-6) low Y (6.85×10-6-7.60×10-6) and Yb (0.57×10-6- 0.72×10-6) value are similar to those of adakites. They show εNd(t) values of -4.2 to -5.8, initial 87Sr/86Sr ratios of 0.7072-0.7077 and εHf(t) values of -1.1 to -4.3. We believe that the Fengxian pluton is mainly derived from subducted sediments in the continental margin environment of the northward subduction of the Paleo-Tethys oceanic slab. The origin of the Fengxian pluton suggests that the Animaqing-Mianlue oceanic crust had subducted under the West Qinling before 237.5 Ma, and the eastern segment of the West Qinling remains a continental arc till the Middle Triassic. Related Articles | Metrics | Comments（0）

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Comparison of Gravel Layers along the Yangtze River between Yichang and Wuhan WANG Heyuan, WANG Zekun, GU Siying, YANG Shuoxuan, ZHAO Ziyao, CHEN Xu Geological Journal of China Universities    2024, 30 (01): 47-55.   DOI: 10.16108/j.issn1006-7493.2022091 Abstract （2000）      PDF（pc） （2101KB）（1337）       Knowledge map    Save Several thick gravel layers are widely distributed in the middle reaches of the Yangtze River, providing useful clues for tracking the evolution of the Yangtze River. Previous studies mainly focused on the chronologies and sedimentary characteristics of gravel layers in local sites, while comparison of gravel layers among different regions has not been extensively investigated. In this study, eleven profiles of gravel layers in Yichang and Wuhan were explored, the morphology and lithology of 1616 gravels were analyzed. Furthermore, geochemical composition of silty sediments intermixed in gravel layers were measured in order to explore the provenance of the sediments, in combination with regional geological conditions. The results show that the dominant inclinations of gravels in the gravel layers of Yichang and Wuhan are different. Gravels in the Yichang gravel layers mainly consist of granite, sandstone, conglomerate and some siliceous rocks. Gravels in Wuhan are dominated by quartzite, with a small amount of flint. Silty sediments in the gravel layers of Yichang are relatively enriched in Ca and Sr, while those in Wuhan are relatively enriched in Fe and Al. Comparison of gravels and silty sediments in the two regions shows that the provenances of gravel layers in the two regions are different. Detritus from the upper reaches of the Yangtze River are important sources of the gravel layers in Yichang, while the gravel layers in Wuhan are sourced from the Dabie Mountains. The results of this study provide new evidence for improving our understanding of the provenances of gravel layers in the middle reaches of the Yangtze River. Related Articles | Metrics | Comments（0）

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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 Abstract （1985）      PDF（pc） （887KB）（1364）       Knowledge map    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 CeO2, 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 CeO2 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. Related Articles | Metrics | Comments（0）

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Comparative Analysis and Enlightenment of Geoscience Knowledge Graphs: A Perspective of Construction Methods and Contents ZHU Yunqiang, SUN Kai, LI Weirong, WANG Shu, SONG Jia, CHENG Quanying, YANG Jie, MU Xinglin, GENG Wenguang, DAI Xiaoliang Geological Journal of China Universities    2023, 29 (3): 382-394.   DOI: 10.16108/j.issn1006-7493.2021111 Abstract （1977）      PDF（pc） （1366KB）（2025）       Knowledge map    Save Geoscience knowledge graphs (GKGs) formally represent geoscience knowledge in a way of directed graph and have strong capabilities in knowledge representation, openness and interconnectivity, and reasoning and prediction. GKGs have been one of the important infrastructures for the development of combining geoscience and artificial intelligence, thereby becoming one of the important research focuses in geoscience. Therefore, many international scientific organizations or groups have successively carried out studies in this domain, and constructed some representative GKGs. However, there is a lack of an in-depth study and analysis of these existing GKGs. To this end, this paper makes a systematic comparative analysis on their general information, construction methods, and main contents. On this basis, some enlightenments about future research of GKGs are discussed. In terms of the construction method, a unified representation framework for GKGs should be built, the source of geoscience knowledge should be enhanced by conflating multi-source and multimodal data, and methods for the representation and computation of geoscience knowledge should be studied. Regarding the contents of GKGs, complex spatiotemporal characteristics, relations, and reasoning rules should be considered. From the perspective of application, methods for assessing quality and making correction for geoscience knowledge should be developed, and application effects of GKGs should be improved. Related Articles | Metrics | Comments（0）

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Oceanic Lithium Cycling and Implications for Carbon Cycle CAO Cheng Geological Journal of China Universities    2024, 30 (03): 269-287.   DOI: 10.16108/j.issn1006-7493.2024022 Abstract （1966）      PDF（pc） （3114KB）（1358）       Knowledge map    Save How the carbon cycle influences the atmospheric carbon dioxide level is of a major concern for Earth’s habitability.The oceanic lithium (Li) cycle can be used to trace carbon cycle because both cycles are controlled by chemical weathering, hydrothermal-seafloor interaction, and marine clay authigenesis which also known as reverse weathering. The variations in seawater Li isotope compositions posit changes in the sink and source processes such as continental weathering intensity and/or rate as well as reverse weathering rate. This paper reviews the global cycle of oceanic lithium and the mass balance for seawater lithium isotopes, focusing on the present-day fluxes and associated isotope fractionation mechanisms. Challenges still remain to better constrain the budgets as well as isotope fractionation factor especially in hydrothermal alteration and reverse weathering. The review also extends to the use of seawater li isotope records in tracing carbon cycle during climate events and critical time periods in the earth history. Collectively, this review highlights the potential as well as limitations of utilizing seawater Li isotope records to trace global carbon cycle in deep time.  Related Articles | Metrics | Comments（0）

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Origin and Genetic Mechanism of the Early Cretaceous Metabasite from the Ramba Area, Tethyan Himalaya YU Youzhi, LIU Zhichao Geological Journal of China Universities    2023, 29 (4): 527-542.   DOI: 10.16108/j.issn1006-7493.2022007 Abstract （1948）      PDF（pc） （4128KB）（1970）       Knowledge map    Save A large number of Early Cretaceous mafic rocks are widely exposed in the Tethyan Himalaya, southern Tibet, China. These rocks provide an important record of the tectonic-magmatic evolution of the north margin of the Indian continent before the Cenozoic Indian-Eurasian collision. Their genesis is critical for reconstructing the evolution history of the Indian passive margin. This paper presents systematical petrographic and geochemical data of the Early Cretaceous metabasites from the Ramba area, eastern Tethyan Himalaya. The Ramba metabasites include amphibolitie-amphibolitic gneisses, which occurred as dikes and lenses in the low-medium grade metasedimentary rocks of the Ramba dome. These Ramba metabasites display tholeiitic affinity and low contents of SiO2 (44.78-47.42 wt%), relatively high contents of MgO (7.31-9.60 wt%) and FeOt (9.68-15.87 wt%) with variable TiO2 contents (0.73-2.16 wt%) and medium to high Mg# values (46.4-63.9). The radiogenic Nd isotopic compositions of the Ramba metabasites (εNd(t) values range from 5.7 to 6.5) are comparable with that of the Indian Oceanic MORB. However, the REEs distribution patterns of the Ramba metabasites are similar to that of the E-MORB, indicating involvement of enriched components in their origin. It is worth noting that the Ramba metabasites do not show depletion in high-field-strength elements (HFSE), and their Nb/U ratios are similar to that of the mantle-derived rocks. Therefore, it can be inferred that the continental crust contamination is not significant in the formation of Ramba metabasites and their enrichment components should be mainly attributed to an enriched mantle source. Consequently, it is speculated that the Ramba metabasites were products of the interaction between magma derived from a depleted asthenospheric mantle and an enriched continental lithospheric mantle. They were generated during the early stage of the breakup of eastern Gondwana (~140 Ma) and were originated from the asthenosphere upwelling that was triggered by early activity of the Kerguelen mantle plume. Related Articles | Metrics | Comments（0）

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Rate, Mechanism, and Geological and Geochemical Effects of Fungi Oromoting Silicate Mineral Weathering LI Zibo, LU Xianca, TENG HuiHenry, LIU Lianwen, QIE Wenkun, PANG Ke, ZHANG Wenxuan, JI Junfeng, CHEN Jun Geological Journal of China Universities    2024, 30 (03): 322-335.   DOI: 10.16108/j.issn1006-7493.2024011 Abstract （1942）      PDF（pc） （2420KB）（1493）       Knowledge map    Save Fungi are widespread and can be found from the Earth’s surface to depths of up to 1.4 km in the continental crust. Based on their ecological habits and nutritional modes, fungi can be categorized as saprotrophic, symbiotic, or parasitic. Hyphae are the basic structural units of fungi. Through their tip-elongated growth and robust metabolic capabilities, fungal hyphae play a unique role in the weathering of silicate minerals, especially those containing nutrient elements. This process regulates essential geological and geochemical processes such as soil formation, mineralization, and the biogeochemical cycling of elements. However, the role of fungi in natural silicate weathering has been relatively overlooked. Our review starts by examining fungal growth patterns, aiming to elucidate their impact on the rate and mechanisms of silicate mineral weathering, as well as their contribution to natural silicate weathering. Through a literature review and in the context of global change, we propose key areas of focus for future research: (1) further quantifying the contribution of fungi to silicate mineral weathering in natural environments, (2) clarifying the coupling of fungal-promoted silicate mineral weathering with geological and geochemical processes, and (3) leveraging functional fungi to improve the efficiency of terrestrial enhanced silicate weathering for carbon removal. These investigations will deepen our understanding of the role of fungi in key surface processes, provide important information for Earth system models (GEOCARB, COPSE, and SCION), enhance the accuracy of predictions regarding the interactions of different spheres in Earth systems, and offer new methods and scientific evidence for the effective carbon sequestration through enhanced silicate weathering. Related Articles | Metrics | Comments（0）

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Equilibrium Isotope Fractionation Effect between Zn-containing Minerals and Aqueous Solution in Contaminated Soils HE Hongtao, GU Yifan, XING Lecai, WANG Yanfang, YANG Yang, CAI Xingping, HE Yuyang Geological Journal of China Universities    2024, 30 (03): 297-311.   DOI: 10.16108/j.issn1006-7493.2024006 Abstract （1904）      PDF（pc） （1441KB）（1949）       Knowledge map    Save Zinc (Zn) isotope fractionation, resulting from multiple physicochemical processes under Earth’s surface conditions, confounds the source identification of pollutants. The determination of Zn isotope fractionation factors between typical Zncontaining minerals and aqueous solutions in contaminated soils is crucial to trace Zn sources using isotopic tools. In this study, we used density functional theory based first principles calculations to investigate the most stable geometries of Zn-containing species, including hydrated Zn2+ complexes, Zn in hydroxy-interlayered minerals (Zn-HIM), Zn-rich phyllosilicates (Talc), Zn-layered double hydroxide (Zn-LDH), and surface adsorbed Zn2+. Based on these optimized configurations, we calculated the equilibrium isotope fractionation factors between the aforementioned structures and Zn2+ in aqueous phases. Our results showed that adsorbed Ⅵ Zn2+ is slightly enriched in 64Zn (Δ66/64Zn=-0.29‰~-0.20‰ ), while adsorbed Ⅳ Zn2+ is enriched in 66Zn (Δ66/64Zn =0.45 ‰~0.73‰ ). Secondary mineral phases are evidently enriched in 66Zn (Δ66/64Zn=0.51‰~1.11‰ ), if Zn transferred to stable crystalline precipitates. Using obtained fractionation factors, we successfully simulated the evolution trends of Zn isotope composition under the influence of single pollution sources (electroplating waste, sphalerite ore, emissions and metallurgical sludge) in equilibrium and Rayleigh fractionation modes. By comparing with available isotope data, these trends facilitate to find out the main source of Zn in contaminated soils. Related Articles | Metrics | Comments（0）

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Petrogenesis of Granite Porphyry in the Yangchuling Tungsten Ore District, Northern Jiangxi HUANG Yu, HUANG Xudong, LU Jianjun, ZHANG Rongqing, WU Jinwei, YAN Jichi Geological Journal of China Universities    2023, 29 (6): 795-808.   DOI: 10.16108/j.issn1006-7493.2022049 Abstract （1883）      PDF（pc） （2668KB）（1234）       Knowledge map    Save Granodiorite, monzogranite porphyry, and granite porphyry are exposed in the Yangchuling tungsten ore district, northern Jiangxi. The granodiorite and monzogranite porphyry were formed in Late Jurassic and derived from the same source and the latter is more evolved than the former. Tungsten mineralization dominantly occurs as veinlet-disseminated within the monzogranite porphyry which is cut by the granite porphyry dykes. In this contribution, zircon U-Pb chronological, petrochemical, and Sr-Nd-Hf isotope geochemical studies are carried out on the Yangchuling granite porphyry, aiming to reveal the petrogenetic differences between the granite porphyry and the monzogranite porphyry and granodiorite in combination with other published data and provide new constraints for tungsten ore genesis. LA-ICP-MS zircon U-Pb dating manifests that the granite porphyry was formed at 144.6±1.8 Ma which is consistent with those of the granodiorite and monzogranite porphyry. The granite porphyry is high-Si, K-enriched, and weakly peraluminous, shows distinctly Ba-, Nb-, Sr-, P-, and Ti-depleted trace element patterns and rightward-sloping REE patterns with negative Eu anomalies, indicating fractional crystallization of feldspar, biotite, apatite, and Ti-Fe oxide minerals, etc. The granite porphyry has whole-rock (87Sr/86Sr)i , εNd(t), εHf(t), and zircon εHf(t) values of 0.711329-0.711726, -5.3 to -4.9, -4.6 to -4.2, and mainly -6.0 to -3.0, respectively, suggesting that its source is dominated by ancient crustal materials. Compared with the granodiorite and monzogranite porphyry, the granite porphyry exhibits higher HFSE, ΣREE contents, AMF values, Sr/V ratios and lower Mg# values, Ti/Zr ratios, whole-rock εHf(t) values, implying that it was derived from a more felsic source and is the product of partial melting of ancient metasediments. Compared with the monzogranite porphyry, the granite porphyry displays higher SiO2 contents, (Na2O+K2O)/CaO, Na2O/CaO, Ba/Sr, Rb/Sr ratios and lower CaO, MgO, TiO2, P2O5 contents, δEu values, manifesting that it has experienced stronger magmatic fractionation. The barren granite porphyry is reflective of a W-poor source, while the source of the granodiorite and monzogranite porphyry is relatively W-rich. Both the W-rich source and magmatic fractionation facilitate the formation of t he Yangchuling tungsten deposit. Related Articles | Metrics | Comments（0）

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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 Abstract （1879）      PDF（pc） （2181KB）（1296）       Knowledge map    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.  Related Articles | Metrics | Comments（0）

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Stagnant Lid Tectonics in the Early Earth and Its Transition to Plate Tectonics YANG Haokun, LI Jianghai Geological Journal of China Universities    2023, 29 (6): 862-871.   DOI: 10.16108/j.issn1006-7493.2022052 Abstract （1857）      PDF（pc） （958KB）（1442）       Knowledge map    Save Plate tectonics has been regarded as the dominant tectonic regime on the earth today, but what was earth’s tectonic regime before the present plate tectonics began and when the present plate tectonics began are still controversial. To understand the evolution of earth and predict its future, we are required to clarify this question. Previously, researchers generally reached a consensus on an uniformitarian view that the early earth’s tectonics was similar to the present plate tectonics. However, with the accumulation of geological data and the progress of research technology, the idea of the transition from stagnant lid tectonics to modern plate tectonics was increasingly accepted. The so called “stagnant lid” refers to single plate around earth surface. In this paper, firstly we review the hypothesis of possible tectonic regime models in the early Earth under the background of stagnant lid tectonics, including heat pipe tectonics, plutonic-squishy lid model, mantle overturn and lid-and-plate tectonics. Then we review the latest research of the transition from stagnant lid tectonics to plate tectonics in early Earth. We believe that the mainstream researchers have reached a roughly consistent framework, that is, the transition from stagnant lid tectonics to plate tectonics occurred in the Meso-Neoarchean, and the modern plate tectonics may have formed in the Neoproterozoic. Related Articles | Metrics | Comments（0）

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Advances on the Analogue Modeling of the Emplacement of Granitic Magma LI Yingying, WANG Bo, CAO Tingting Geological Journal of China Universities    2023, 29 (4): 543-558.   DOI: 10.16108/j.issn1006-7493.2022055 Abstract （1853）      PDF（pc） （7635KB）（1628）       Knowledge map    Save Regional tectonics not only facilitate the ascent and emplacement of the granitic intrusions but also control the final shapes of the intrusions. Analogue modeling is a critical method to study the magma emplacement. This paper reviewed the experimental set-up, materials and scaling used in previous analogue models related to magma emplacement, and summarized the influence of various parameters on the geometry of the intrusions in various tectonic settings. We suggested that: (1) the intrusion geometry is controlled by the characteristics of the country rocks in pre-kinematic static settings during tectonic quiescent stage. (2) In syn-kinematic settings during tectonic active stage, the intrusion geometry and deformation patterns of plutons are influenced by several parameters, including the thickness and rheological layering of the country rocks, velocity and total distance of displacement, velocity and total volume of magma injection, position of the injection inlet (magma channel), relative timing of tectonic activity and magma emplacement. Deformation can in turn control the shape of intrusions. (3) The parameters, such as displacement velocity and injection velocity in different settings, have similar impact on the intrusion geometry. In addition, some limitations of analogue modeling method are also discussed. The CT technique and numerical modeling methods are suggested to be profitable supplementation of analogue modeling for the study in magma emplacement.  Related Articles | Metrics | Comments（0）

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Investigation of Oedometer Test and Mechanism of Soft Soil Improved Using Microbial Composite Material LIU Qing, LIN Jun, XIE Jiamin, QIN Pengfei Geological Journal of China Universities    2023, 29 (3): 487-496.   DOI: 10.16108/j.issn1006-7493.2021114 Abstract （1845）      PDF（pc） （2723KB）（1806）       Knowledge map    Save Microbial induced carbonate precipitation (MICP), as an eco-friendly technology, has been used to improve the mechanical properties of soil. However, it is difficult to apply the MICP to soft soil foundation treatment due to the poor engineering properties. The MICP-sand drain combined with vacuum drainage and MICP-biochar were introduced to the soft soil, and the amount of sand drain and biochar mixing ratio were studied using oedometer test. The microstructures were investigated to reveal the precipitation patterns of calcium carbonate by using SEM and XRD tests. The results showed that porosity ratio decreased with the increase of in number of sand drain and biochar mixing ratio. The coefficient of compressibility and modulus of compression could be improved when the contents of biochar were in a certain range (about 8%). The analysis of calcium carbonate content showed reveal that the amount of calcium carbonate decreased gradually with the increase of in depth, which presented presents non-uniformity of calcium carbonate distribution. Additionally, a large amount of calcium carbonate was observed in the two methods, which were deposited on the contact of soil particles. The crystal type of calcium carbonate was determined as vaterite. Related Articles | Metrics | Comments（0）

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Provenance and Tectonic Setting Analysis of the Wufeng-Longmaxi Formation Shale in the Sichuan Basin and Its Surrounding Area PENG Hao, CHEN Lei, HU Yunpeng, LU Chang, HENG De, WEN Ran, TAN Xiucheng, QIN Hexing Geological Journal of China Universities    2024, 30 (02): 231-240.   DOI: 10.16108/j.issn1006-7493.2022097 Abstract （1844）      PDF（pc） （1053KB）（1193）       Knowledge map    Save The Wufeng-Longmaxi Formation shales show great variations in sedimentological, mineralogical and geochemical characteristics across the Sichuan Basin and its surrounding areas. Provence and sources are the basis in determining  composition, mineralogy, and brittleness of shale. In this paper, we analyze the geochemical characteristics, source rock properties and tectonic setting of the Wufeng-Longmaxi shale in the Sichuan Basin and its surrounding areas based on major elements, trace elements, and rare earth elements data. The results show that the main components of the Wufeng-Longmaxi shale are SiO2, CaO and Al2O3 in the Sichuan Basin and its surrounding areas. From the southwest to south -southeast -northeast Sichuan, the SiO2 content in the Wufeng-Longmaxi Formation shale increases gradually, while the CaO content decreases gradually. The La/Yb-REE diagram shows that the source rocks of the Wufeng-Longmaxi Formation shale have certain variations in different areas of Sichuan Basin and its surrounding areas. The source rocks of the Wufeng-Longmaxi Formation shales are similar in southwest Sichuan and South Sichuan, mainly consisting of alkaline basalt, sedimentary rocks and granites. The shale source rocks of southeast Sichuan are mainly composed of granite and alkaline basalt, while the shale source rocks of northeast Sichuan are mainly composed of sedimentary rocks and granites. The ICV index analyses reveal that the source of the Wufeng-Longmaxi shales in southwest and south Sichuan is a result of rapid deposition of the first cycle of the near source, while the Wufeng-Longmaxi shales in southeast and northeast Sichuan have undergone recycling or strong chemical weathering. The analyses of Sc/Cr-La/Y diagram and other related parameters indicate that the Wufeng-Longmaxi Formation shale in the Sichuan Basin and its surrounding areas was deposited in a passive continental margin. Related Articles | Metrics | Comments（0）

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Regional Comparative Study on Mineralogy and Geochemistry of Carbonate Rocks from the Upper Carboniferous in Tongling Ore District WANG Jiayu, XU Liang, XIE Qiaoqin, LIU Tong, ZHOU Yuefei, LI Zhensheng, XU Xiaochun, CHEN Tianhu Geological Journal of China Universities    2023, 29 (4): 514-526.   DOI: 10.16108/j.issn1006-7493.2022008 Abstract （1842）      PDF（pc） （3286KB）（628）       Knowledge map    Save This paper presents a mineralogical and element geochemical study of carbonate rocks of the Upper Carboniferous Huanglong-Chuanshan Formation section from Tongling and Chaohu, Anhui Province. The results show that (1) the base of Huanglong Formation in Tongling is a set of dolostone containing framboidal pyrite; (2) the lower part of Huanglong Formation to the top of Chuanshan Formation are limestones; and (3) from bottom to top of section, mineral associations are dolomite+kaolinite +pyrite+quartz at the bottom of the Huanglong Formation → calcite+kaolinite+quartz (the middle and lower Huanglong Formation) → calcite+illite+quartz (the upper Huanglong Formation and the Chuanshan Formation), respectively. However the Huanglong-Chuanshan Formation in Chaohu are limestones composed of calcite with kaolinite and quartz, and the content of kaolinite tends to increase from the bottom of Huanglong Formation to the top of Chuanshan Formation. Also, carbonates of the Huanglong-Chuanshan Formation in Tongling (especially the dolomites at the bottom of the Huanglong Formation) show much higher V/Cr, Ni/Co, and V/Sc ratios, and Ce and Fe, Mn are uncorrelated while these parameters are positively correlated for Chaohu carbonates. Mineralogical and geochemical features suggest that carbonates at the bottom of the Huanglong Formation in Tongling were deposited in a relatively stable reducing environment, whereas carbonates in the middle and upper Huanglong Formation and Chuanshan Formation were deposited in a stable and weak oxidizing environment, and carbonates in Chaohu were formed in a more oxidizing and high-energy volatile environment. Combined with the previous studies, this study suggests that the existence of the ancient island in Tongling may be the main reason why the sedimentary environment of Tongling is different from that in Chaohu. Also, the sedimentary environment in Tongling area is favorable for the formation of colloform Pyrite. Related Articles | Metrics | Comments（0）