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organic Carbon Isotopic Evolution during the Ediacaran-Cambrian Transition Interval in Eastern Guizhou,South China: Paleoenvironmental and Stratigraphic Implications

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Acta Geologica Sinica(English Edition) 2007年第2期81卷 194-203页

作者： YANG Xinglian ZHU Maoyan GUO Qingjun ZHAO Yuanlong College of Resource and Environment Guizhou University Guiyang Guizhou 550003 State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing Jiangsu 210008 State Key Laboratory of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang Guizhou 550002

Secular variations of carbon isotopic composition of organic carbon can be used in the study of global environmental variation, the carbon cycle, stratigraphic delimitation, and biological evolution, etc. organic carbon isotopic analysis of the Nangao and Zhalagou sections in eastern Gnizhou reveals a negative excursion near the Precambrian-Cambrian boundary that correlates with a distinct carbonate carbon isotopic negative excursion at this boundary globally. Our results also demonstrate that several alternating positive and negative shifts occur in the Meishucunian, and an obvious negative anomaly appears at the boundary between the Meishucunian and Qiongzhusian. The isotope values are stable in the middle and lower parts but became more positive in the upper part of the Qiongzhusian. Evolution of organic carbon isotopes from the two sections in the deepwater facies can be well correlated with that of the carbonate carbon isotopes from the section in the shallow water facies. Integrated with other stratigraphic tools, we can precisely establish a lower Cambrian stratigraphic framework from shallow sheff to deep basin of the Yangtze Platform.

关键词： organic carbon isotope chemostratigraphy Cambrian Ediacaran Gnizhou Yangtze Platform

Dynamics of soil organic carbon following land-use change:insights from stable C-isotope analysis in black soil of Northeast China

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Acta Geochimica 2018年第5期37卷 746-757页

作者： Chenglong Tu Congqiang Liu Timothy A.Quine Matthew William Jones Taoze Liu Longbo Li Wenjing Liu State Key Laboratory of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Key Laboratory of Environmental Pollution Monitoring and Disease Control Ministry of Education Guizhou Medical University School of Geography College of Life and Environmental Sciences Hatherly Laboratory University of Exeter Key Laboratory of Shale Gas and Geoengineering Institute of Geology and Geophysics Chinese Academy of Sciences

Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and *** aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0–100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C_4) and from natural vegetation (C_3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0–10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C_4 above 30 cm soil depth increased by 4.5%–5% or 0.11–0.12 g·kg^(-1) on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation *** increase in the percentage of C_4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C_4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment.

关键词：土壤有机物同位素分析中国东北器官动力学稳定陆地

Anaerobic oxidation of methane: Geochemical evidence from pore-water in coastal sediments of Qi’ao Island (Pearl River Estuary), southern China

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Chinese Science Bulletin 2006年第16期51卷 2006-2015页

作者： WU Zijun ZHOU Huaiyang PENG Xiaotong CHEN Guangqian Guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate School of Chinese Academy of Sciences Beijing 100039 China

The concentrations of CH4 and SO42? in pore-water and the carbon isotope compositions of total dissolved inorganic (ΣCO2) and CH4 were de- termined for three coastal sedimentary cores col- lected from Qi’ao Island (Pearl River Estuary), southern China. Results show that methane concen- tration changes dramatically at the base of the sul- fate-reducing zone and sulfate concentration gradi- ents are linear for all stations. In addition, the carbon isotope of methane becomes heavier at the sul- fate-methane transition (SMT), which causes ΣCO2-δ 13C to become the minimum. The geo- chemical profiles of pore-water render indirect evi- dence for anaerobic oxidation of methane (AOM). Based on numerical modeling of AOM and sul- fate-reducing rates, the portion of total sulfate reduc- tion occurring via AOM is 9.0%, 84% and 45.5%, re- spectively, and the percentage of ΣCO2 added to the pore-water is 4.7%, 72.4% and 29.45% correspond- ingly for three sites. Furthermore, it is found that the methane concentration, methane diffusive flux and the depth of SMT are controlled by the quantity and quality of sedimentary organic matter incorporated into the sediments. The great amount of organic material is favorable for rapid depletion of sulfate via sedimentary organic matter degradation, and on the other hand, causes the increase of the methane flux in the SMT, which results in a portion of sulfate re-duction supported by AOM. Accordingly, the SMT was shifted towards the sediment surface.

关键词：缺氧氧化甲烷硫酸盐沉积珠江河口地球化学

Mercury transformation processes in nature: Critical knowledge gaps and perspectives for moving forward

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Journal of Environmental Sciences 2022年第9期34卷 152-165页

作者： Zhiyuan Gao wang Zheng Yanbin Li Yurong Liu Mengjie Wu Shouying Li Ping Li Guangliang Liu Xuewu Fu Shuxiao wang Feiyue wang Yong Cai Xinbin Feng Baohua Gu Huan Zhong Yongguang Yin centre for Earth Observation Science and Department of Environment and GeographyUniversity of ManitobaWinnipegMB R3T 2N2Canada Institute of Surface-Earth System Science Tianjin UniversityTianjin 300192China Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education and College of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China State Key Laboratory of Agricultural Microbiology Huazhong Agricultural UniversityWuhan 430070China School of the Environment Nanjing UniversityState Key Laboratory of Pollution Control and Resource ReuseNanjing 210023China State Key Laboratory of Environmental geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Department of Chemistry and Biochemistry Florida International UniversityMiamiFL 33199USA School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control Tsinghua UniversityBeijing 100084China Environmental Sciences Division Oak Ridge National LaboratoryOak RidgeTennessee 37831USA Environmental and Life Sciences Program(EnLS) Trent UniversityPeterboroughOntario K9L 0G2Canada Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China

The transformation of mercury(Hg) in the environment plays a vital role in the cycling of Hg and its risk to the ecosystem and human health. Of particular importance are Hg oxidation/reduction and methylation/demethylation processes driven or mediated by the dynamics of light, microorganisms, and organic carbon, among others. Advances in understanding those Hg transformation processes determine our capacity of projecting and mitigating Hg risk. Here, we provide a critical analysis of major knowledge gaps in our understanding of Hg transformation in nature, with perspectives on approaches moving forward. Our analysis focuses on Hg transformation processes in the environment, as well as emerging methodology in exploring these processes. Future avenues for improving the understanding of Hg transformation processes to protect ecosystem and human health are also explored.

关键词： Mercury oxidation reduction methylation demethylation isotope fractionation

Low-mature gases and typical low-mature gas fields in China

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Science China Earth Sciences 2008年第2期51卷 312-320页

作者： XU YongChang waNG ZhiYong waNG XiaoFeng ZHENG JianJing DU HongYu Key Laboratory of Gas geochemistry Chinese Academy of SciencesLanzhou 730000China Research Institute of Turpan-Hami Oil field Company Hami 839009China

No natural gas pool of industrial importance could be formed at the low-evolution stage of organic matter. In the 1980s, on the basis of the development in exploration practice, the hypotheses of bio-thermo-catalytic transitional zone gases and early thermogenic gases were proposed. The lower-limit Ro values for the formation and accumulation of natural gases of industrial importance have been expanded to 0.3%―0.4%. In the light of the two-stage model established on the basis of carbon isotope fractionation in coal-type natural gases, the upper-limit Ro values have been set at 0.8%―1.0%. In terms of the geological practice in the low-mature gas zones and China's main coal-type gas fields, it is feasible and proper to set the upper-limit Ro value of low-mature gases at 0.8%. Supper-large gas fields such as the Urengoy gas field in western Siberian Basin should belong to low-mature gas fields, of which the natural gas reserves account for more than 20% of the global proven reserves, providing strong evidence for the significance of such a type of resources. The proven natural gas reserves in the Turpan-Hami Basin of China have almost reached 1000 × 108 m3. The main source rocks in this area are the Jurassic Xishanyao Formation, which occurs as a suite of coal series strata. The corresponding thermal evolution indices (Ro ) are mainly within the range of about 0.4%―0.8%, the δ 13C1 values of methane vary between-44‰ and-39‰ (correspondingly Ro =0.6%―0.8%), and those of ethane are within the range of-29‰―-26‰, indicating that natural gases in the Turpan-Hami Basin should be designated to coal-type low-mature gases. The light hydrocarbon evolution indices of natural gases also fall within the area of low evolution while the precursor type of light hydrocarbons also shows the characteristics of the coal-type. The geological background, carbon isotopic composition and light hydrocarbon index all provide strong evidence suggesting that the proven natural gases in the Turpan

关键词： Turpan-Hami Basin natural gas low-mature gas humus isotope

Isotopic compositional Characteristics of Terrigenous Natural Gases in China

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Chinese Journal Of geochemistry 1993年第1期12卷 14-24页

作者：沈平徐永昌 State Key Laboratory of Gas geochemistry Lanzhou Institute of GeologyAcademia SinicaLanzhou730000

The C and H isotopic compositions of the methane in more than 160 gas samples from 10 basins in China are presented in this *** natural gases are classified as four types: biogenic gas ,bio-thermocatalytic transitional gas, gas associated with condensate oil ,and coal-type gas. The isotopic compositions of these gases closely related to the depositional basins, the types of organic matter,the stages of thermal evolution and the genetic characteristics of different gas *** of the C and H isotopic compositions of terrigenous natural gases will provide valua-ble information on the prospecting and development of natural gases of different genetic types.

关键词：同位素地球化学油气资源氧同位素陆地沉积盆地分级碳同位素

Carbon, oxygen and boron isotopic studies of Huangbai-shuwan witherite deposit at Ziyang and Wenyuhe witherite deposit at Zhushan

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Science China Earth Sciences 2003年第12期 1273-1291页

作者：吕志成刘丛强刘家军赵志琦 Jilin University Changchun 130026 China The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sci-ences Guiyang 550002 China Open Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sci-ences Guiyang 550002 China Open Laboratory of Ore Deposit geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Being stratiform or stratoid, the Huangbaishuwan witherite deposit at Ziyang and the Wenyuhe witherite-barite deposit at Zhushan occur in the lower Lower Cambrian siliceous rocks and the orebodies are remarkably controlled by lithological character and petrography. Boron, carbon and oxygen isotopic studies of witherite, barytocalcite and calcite have shown that the car-bon, involved in the formation of these minerals, was derived mainly from hydrocarbons and bio-genetic gases resulting from degradation, polycondensation and dehydroxylation of bio-organic matter in sediments at the early stage of diagenesis; the boron was a mixture of boron in pore wa-ter and that released in the process of degradation of organic matter, with a minor amount of boron from cycling brines in the deep interior of the basin. Boron, carbon and oxygen isotopic studies unanimously demonstrated that witherite was precipitated in this sort of organic carbon-rich pore water medium during the early stage of diagenesis. Extensive occurrence of biodetritus and clastic texture in witherite ores strongly evidenced that Ba2+ was concentrated and settled down in the form of bio-barite on the seafloor as a result of biological processes, thereafter forming the initially enriched orebodies of barium deposits. Biological processes in seawater and early diagenesis in sediments are the major ore-forming mechanisms of witherite deposits in the region studied.

关键词： witherite deposit boron isotope carbon and oxygen isotopes early diagenesis bio-barite.

Petroleum Retention,Intraformational Migration and Segmented Accumulation within the organic-rich Shale in the Cretaceous Qingshankou Formation of the Gulong Sag,Songliao Basin,Northeast China

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地质学报:英文版 2023年第5期97卷 1568-1586页

作者： HUANGFU Yuhui ZHANG Jinyou ZHANG Shuichang waNG Xiaomei HE Kun GUAN Ping ZHANG Huanxu ZHANG Bin waNG Huajian School of Earth and Space Sciences Peking UniversityBeijing 100871China Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China Exploration and Development Research Institute of Daqing Oilfield Co. Ltd.DaqingHeilongjiang 163712China Key Laboratory of Petroleum geochemistry CNPCBeijing 100083China Grand Energy and Technology Co. Ltd.SuzhouJiangsu 215000China

In this study,organic geochemical and petrological analyses were conducted on 111 shale samples from a well to understand the retention,intraformational migration and segmented accumulation(shale oil enrichment in different intervals is unconnected)features of shale oil within the organic-rich shale in the Qingshankou Formation of the Gulong *** study shows that retained petroleum characteristics in the investigated succession are mainly influenced by three factors:organic richness,intraformational migration and segmented *** matter richness primarily controls the amount of retained petroleum,especially the‘live’component indicated by the S_(2)value rather than the total organic carbon(TOC)figure *** negative expulsion efficiencies determined by mass-balance calculations of hydrocarbons reveal that petroleum from adjacent organic-rich intervals migrates into the interval of about 2386-2408 m,which is characterized by high free hydrocarbon(S_(1)),OSI and saturated hydrocarbons content,along with a greater difference inδ^(13)C values between polar compounds(including resins and asphaltenes)and saturated *** depth-dependent heterogeneity of carbon isotope ratios(δ^(13)C)of mud methane gas,δ^(13)C of extracts gross composition(SARA),δ^(13)C of kerogen and SARA content of extracts suggest that the studied succession can be subdivided into four *** shale oil sealing enrichment character in each interval is further corroborated by the distinctδ^(13)C values of mud methane gas in different *** to the migration of petroleum into the 2386-2408 m interval,the S_(1),OSI and saturated hydrocarbons content of the interval show higher relative *** maturity of organic matter in the 2471-2500 m interval is at the highest with the smaller size molecular components of the retained ***,favorable‘sweet spots’may be found in the 2386-2408 m interval and the 2471-2500 m interval,according to the experiment resul

关键词： shale oil oil retention intraformational migration segmented accumulation Gulong Sag

Carbon isotope distribution in aromatic nuclei and aliphatic side chains of sedimentary organic matter

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Chinese Science Bulletin 1995年第9期40卷 753-757页

作者：刘文汇于心科张柏生 State Key Laboratory of Gas geochemistry Lanzhou Institute of Geology Chinese Academy of SciencesLanzhou 730000 China

isotope composition analysis is an important technique in researches on oil-gas-sourcecorrelation and evolution of sedimentary organic matter. Many δ13C1-Ro relationship mod-els for natural gas have been suggested, and almost all of them indicate that naturalgas derived from the type-Ⅲ kerogen is isotopically heavier than that from the type-Ⅰ

关键词： carbon isotope biothermocatalytic transitional zone gas oxidation of organic matter oil-source correlation isotope fractionation.