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Contribution of Oxygenic Photosynthesis to Palaeo-Oceanic Organic Carbon Sink Fluxes in early cambrian Upper Yangtze Shallow Sea: Evidence from Black Shale Record

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Journal of Earth Science 2016年第2期27卷 211-224页

作者： Kunyu Wu Tingshan Zhang Yang Yang Yuchuan Sun Daoxian Yuan State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University School of Geographical Sciences Southwest University Karst Dynamics Laboratory MLR and GZAR Institute of Karst GeologyCAGS

The extensive transgression that occurred on the Yangtze Plate in early cambrian led to a massive organic carbon pool in the Niutitang Formation. A black shale core section from 3 251.08 to 3 436.08 m beneath the Earth＇s surface was studied to estimate the contribution of oxygenic photosynthesis to organic carbon sink fluxes in early cambrian Upper Yangtze shallow sea. Results indicate that the oxygenic photosynthesis played the most important role in carbon fixation in early cambrian. Organic carbon sink was mainly contributed by photosynthetic microorganisms, e.g., cyanobacteria, algae and archaea. The Niutitang Formation was formed in a deep anoxic marine shelf sedimentary environment at a sedimentation rate of ~0.09±0.03 mm/yr. The initial TOC abundance in Niutitang shale ranged from 0.18% to 7.09%, with an average of 2.15%. In accordance with the sedimentation rate and initial TOC abundance, organic carbon sink fluxes were calculated and found to range from 0.21 to 8.10×10~3 kg/km^2·yr^（-1）, especially the organic carbon sink fluxes in depth between 3 385 and 3 470 m range from 3.80 to 8.10×10~3 kg/km^2·yr^（-1）, with an average of ~6.03×10~3 kg/km^2·yr^（-1）, which is much higher than that of contemporary marine sediments. The organic carbon sink fluxes of Niutitang shale are equal to 0.56 to 21.61×10~3 kg/km^2·yr^（-1） net oxygen emitted into the early cambrian ocean and atmosphere, this emitted oxygen may have significantly promoted the oxygen level of the Earth＇s surface and diversification of metazoans.

关键词： oxygenic photosynthesis organic carbon sink black shale early cambrian UpperYangtze shallow sea.

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Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the early cambrian,SW China:Constraints from in situ LA-ICP-MS Analysis of Pyrite

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 416-429页

作者： YANG Zhen FU Yong LI Chao CAI Xi GUO Chuan College of Eco-Environmental Engineering Guizhou Minzu UniversityGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and the Environment Ministry of EducationGuizhou UniversityGuiyang 500025China National Research Center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China

A polymetallic layer is usually developed at the bottom of the early cambrian black shale in Guizhou *** mineral that makes up the polymetallic layer is related to the sedimentary *** analyze the differentiation mechanism between polymetallic deposits(Ni-Mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of *** results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan *** isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive Yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional *** sulfur in the Ni-Mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from ***,the Ni-Mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

关键词： sedimentary environment black shale polymetallic layer pyrite early cambrian

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Nitrogen isotope stratigraphy of the early cambrian successions in the Tarim Basin:Spatial variability of nitrogen cycling and its implication for paleo-oceanic redox conditions

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Acta Geochimica 2024年第4期43卷 785-801页

作者： Bi Zhu Xuefeng Li Lu Ge Yongquan Chen Institute of Earth’s Critical Zone School of Earth Sciences and EngineeringHohai UniversityNanjing 210098China Research Institute of Exploration and Development Tarim Oil Field CompanyPetroChinaKorlaChina

The early cambrian represents a critical time period characterized by extraordinary biological innovations and dynamic redox conditions in *** isotopic signatures of ancient sediments have the potential to elucidate the evolutionary path of marine redox states and the biogeochemical nitrogen cycle within the water column of the early cambrian *** existing research on this topic has predominantly focused on South China,the exploration of other continental margins has been limited,leaving contradictory hypotheses *** this study,pairedδ^(15)N andδ^(13)C org analyses were performed on the Lower cambrian successions from the Shiairike section(inner ramp)and Well Tadong 2(deep shelf/basin)in the northwestern and eastern Tarim Basin,*** data from the Shiairike section reveal a discernible shift in the operation of different nitrogen cycles for the black chert-shale unit,also referred to as the black rock series in Chinese literature,of the Yurtus Formation(Fortunian stage to lower Stage 3).Oscillatingδ^(15)N values for its lower part are suggestive of alternating anaerobic assimilation of NH 4+and denitrification/*** is likely attributed to a shallow,unstable chemocline consistent with the upwelling and incursion of deep,anoxic waters during a major *** contrast,aerobic nitrogen cycling,indicated by positiveδ^(15)N values of>2‰,dominated the upper part alongside a reduction in upwelling *** the other hand,theδ^(15)N signatures of Xishanbulake and Xidashan Formations of Well Tadong 2,which encompass a time interval from the cambrian Fortunian Age to Age 4,are indicative of N_(2)fixation by diazotrophs as the major nitrogen *** two studied intervals,although not time-equivalent,exhibit separated states of nitrogen cycling at least during the deposition of the Yurtus black rock *** spatially different nitrogen cycling of the studied sections is compatible with a redox-stratified ocean dur

关键词： Nitrogen isotopes early cambrian Tarim Black rock series

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Sponge spicules in phosphorites of the early cambrian Gezhongwu Formation,Zhijin,Guizhou

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Progress in Natural Science:Materials International 2004年第10期14卷 56-62页

作者： YANG Ruidong 1 ,QIAN Yi 2 ,ZHANG Jie 1 ,ZHANG Weihua 1 ,JIANG Lijun 1 and GAO Hui 1 (1.Guizhou University of Technology,Guiyang550003,China 2.Institute of Geology and Paleontology,Chinese Academy of Sci-ences,Nanjing210008,China) Guizhou Univ. of Technol. Guiyang 550003 China Inst. of Geol. and Paleontology Chinese Acad. of Sci. Nanjing 210008 China

Phosphorites occurring at the bottom of the cambrian system contain abundant small shelly fossils,which are the prod-uct of the first episode of life explosion in the *** was previously reported that the small shelly fossils are dominated by hy-olithids,olivooids,zhijinitids,conodontomorphs,yubelichitids,camenitids and algae,with minor amounts of sponge *** amounts of sponge spicules,diverse in form,have been found for the first time in the Gezhongwu Formation phosphorites at Shixing,Zhi-jin County,Guizhou Province,of which such spicules as diaxon-triactins,diaxon-tetractins,pentaxon-pentactins and hexon-hexactins ac-count for30%.These spicules constitute the sponge clastic phosphorites made up of sponge ***,it is also expected that the radiation and diversity of sponge animals started as early as in the earliest early *** and burying environment of sponge animal are discussed in the paper.

关键词： sponge animal Gezhongwu Formation early cambrian Guizhou

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Trace elements and stable isotopic geochemistry of an early cambrian chert-phosphorite unit from the lower Yurtus Formation of the Sugetbrak section in the Tarim Basin

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Science China Earth Sciences 2014年第3期57卷 454-464页

作者： YAO ChunYan MA DongSheng DING HaiFeng ZHANG XiaoYong HUANG Hui School of Earth Sciences and Engineering State Key Laboratory for Mineral Deposits Research Nanjing University Nanjing Center China Geological Survey Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Jiangsu Environment Monitoring Center Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Exploration Department of Earth Sciences Sun Yat-sen University

A chert-phosphorite unit from the Sugetbrak section in the Tarim Basin was analyzed for rare earth elements(Ce,Eu),redox sensitive proxies,and carbon isotopic compositions(??13C carb and??13C org)in the lower Yurtus Formation of the early cambrian *** sensitive element ratios(Th/U,V/Cr,Ni/Co,and V/Sc)were employed to determine the palaeoenvironmental conditions during this *** ratios indicated that the depositional environment of the chert-phosphorite-black shale unit ranged from suboxic to *** Ce and positive Eu anomalies in the chert-phosphorite assemblages of the studied Yurtus Formation indicated the existence of a redox-stratified ocean,similar to that of South *** or upward expansion of the deep water-mass probably reached the shallow marine zone after the formation of the Yurtus *** characteristics of the negative Ce anomaly may be due to phosphoritic inheritance from the Ce-depleted signature of the overlying water *** hydrothermal inputs and reduced detrital supplies of the deep water caused by the upwelling affected certain redox sensitive elements in the sedimentary basin.??13C carb and??13C org negative excursions in the Yurtus chert-phosphorite unit may be related to a transgression phase when episodic basinal upwelling moved12C-and P-rich waters from the pelagic basin floor to the continental *** carbon isotopic compositions in the Yurtus chert-phosphorite assemblages may have suffered from diagenetic alteration,they can be used to probe diagenetic ***-proxy geochemical studies indicated that the??13C carb values of the Yurtus chert-phosphorite assemblages might be considered reflections of a predominantly suboxic environment that was subsequently affected by hydrothermal inputs due to the upwelling.

关键词： redox sensitive element ratios carbon isotope sedimentary environment early cambrian Tarim Basin

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A New Vetulicolian from the early cambrian Chengjiang Fauna in Yunnan of China

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Acta Geologica Sinica(English Edition) 2003年第3期77卷 281-287页

作者： CHENAilin FENGHongzhen ZHUMaoyan MADongsheng LIMing DepartmentofEarthScience NanjingUniversityNaniingJiangsu210093 NanjingInstituteofGeologyandPalaeontology ChineseAcademyofSciencesNanjingJiangsu210008

The genus and species Yuyuanozoon magnificissimi gen. et sp. nov., a new fossil vetulicolian, is reported from the early cambrian Chengjiang Fauna in Yunnan of China. It has a bipartite body plan and five pairs of chain-formed gill sacs, showing the general characteristics of Ventulicolia. However, the exclusive 'atrial cavity' and external gill observed indicate that the new form is different from those previously described as vetulicolians, probably representing a lineage developed within deuterostomes and more primitive than urochordates.

关键词： vetulicolian Chengjiang Fauna early cambrian Chengjiang Yunnan China

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New Bradoriid Arthropods from the early cambrian Balang Formation of Eastern Guizhou, South China

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Acta Geologica Sinica(English Edition) 2010年第1期84卷 56-68页

作者： PENG Jin FENG Hongzhen FU Xiaoping ZHAO Yuanlong YAO Lu College of Earth Science and Engineering Nanjing University Nanjing Jiangsu 210093 China College of Resource and Environment Engineering Guizhou University Guiyang Guizhou 550003 China State Key Laboratory Palaeobiology and Stratigraphy （NIGP CAS） Nanjing Jiangsu 210008 China Paleontological Museum ofShenzhen Xianhu Botanical Garden Shenzhen 5180004 China.

The early cambrian Balang Formation is comprised of mudrock and shale, which was deposited in a shelf environment in the eastern part of Guizhou, south China. The Balang Fauna, which consists of seven phyla, occurs in the middle and upper parts of the Balang Formation. Arthropods are important constituents of the Balang Fauna and include a great number of trilobites, large bivalved arthropods, and newly-discovered well-preserved bradoriid fossils. The bradoriids present include three genera and four species ： Comptaluta inflata （Cheng, 1974） emend Hou et al., 2002; Comptaluta kailiensis sp. nov., and Alutella elongeta sp. nov, Aluta sp. This faunal assemblage in the Balang Formation is distinguished from the Tsunyiella Chang, 1964, Songlinella Yin, 1978 and Kunmingella Hou, 1956 assemblage which occurs in the Niutitang and Mingxinsi formations of the Yangtze Platform in middle region of Guizhou and which is earlier than the Balang Formation in age. However, this assemblage resembles the Comptaluta Opik, 1968 assemblage from the early cambrian Heilinpu Formation in Wuding County, Yuanan Province and from the Ordian Stage of the cambrian of Australia. The great abundance of Comptaluta Opik, 1968 and overall taxonomic diversity of the Comptaluta Opik, 1968 assemblage set it distinctly apart from theAlutella Kobayashi et Kato, 1951 and Aluta Hou, 1956 assemblages of the Balang Formation. Alutella Kobayashi et Kato, 1951 and Aluta Hou, 1956 also occur in the early cambrian Niutitang Formation of the Yangtze Platform of Guizhou. Individual Bradoriids from the Balang Formation are characterized by large size （〉3 mm）. The discovery of new Bradoriid assemblages not only expands the group＇s geographical range and assemblage affinities, but also indicates that Bradoriids migrated eastward from shallow-water to deeper-water environments during the early cambrian, indicating that they were capable of life in deeper-water, and adaptation to a new ecological setting.

关键词： Bradoriids Balang Formation early cambrian Guizhou China

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Internal Microanatomy and Zoological Affinity of the early cambrian Olivooides

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Acta Geologica Sinica(English Edition) 2016年第1期90卷 38-65页

作者： Han Jian LI Guoxiang KUBOTA Shin OU Qiang TOSHINO Sho WANG Xing YANG Xiaoguang UESUGI Kentaro MASATO Hoshino SASAKI Osamu KANO Harumasa SATO Tomohiko KOMIYA Tsuyoshi early Life Institute and Department of Geology and State Key Laboratory of Continental Dynamics Northwest University229 Taibai RoadXi'an 710069China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Seto Marine Biological Laboratory Field Science Education and Research CenterKyoto UniversityShirahamaNishimuroWakayama 649-2211Japan early Life Evolution Laboratory School of Earth Sciences and ResourcesChina.University of GeosciencesBeijing 100083China Graduate School of Fisheries Sciences Kitasato University1-15-1 KitasatoSagamiharaKanagawa 252-0373Japan Japan Synchrotron Radiation Research Institute(JASRI)1-1-1 Kouto Sayo-choSayo-gunHyogoJapan Tohoku University Museum Tohoku University6-3 AobaAramakiAoba-kuSendaiJapan Department of Earth Science and Astronomy Graduate School of Arts and SciencesThe University of TokyoTokyo 153-8902Japan

The early cambrian pentamerous microfossil Olivooides/Punctatus in South China, which is characterized by a diagnostic stellate tubular apex, has been well-known for its almost complete development sequence that can be confidently traced from embryos and hatched juveniles, to conical adults. However, its zoological affinity remains highly controversial. Here we describe the internal microanatomic structures of the soft-body inside the peridermal theca of Olivooides multisulcatus Qian, 1977, including interradial pairs of tentacles, adradial and perradial frenula, perradial oral marginal lappets and twins of perradial gastric saccule-like humps as well as a circular velarium with striated coronal muscles. Particularly, one specimen shows bifurcated velarial canals along the bell aperture. Both the components of the soft-body and the external theca （or cyst） are arranged in perfect pentaradial symmetry. These characteristics are more compatible with those of living cubomedusans and co-occurring cambrian athecate embryonic cubozoans. Concerning the presence of peridermal theca, Olivooides most likely represents an extinct thecate stem-group cubomedusae but devoid of both perradial eyes and specialized pedalia. The well-grown soft body inside the peridermal tube displays a set of mixed features of both polyp and medusa.

关键词： Embryos periderm cnidarians cubozoan early cambrian Kuanchuanpu Formation

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Marine Redox Conditions in the early cambrian Ocean: Insights from the Lower cambrian Phosphorite Deposits, South China

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Journal of Earth Science 2016年第2期27卷 282-296页

作者： Haifeng Fan Hanjie Wen Xiangkun Zhu State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Institute of Geology Chinese Academy of Geological Sciences

It is generally considered that a significant change in oceanic redox conditions occurred during the Ediacaran-cambrian transition. However, there are currently two major conflicting views on the degree of oxygenation of deep water（oxic vs. ferruginous） during this interval. To date, the oxygenation conditions of the early cambrian ocean have not been well constrained. The oxygenation magnitude and mechanism of the early cambrian ocean could be critical to the significant biological evolution of the ＂cambrian Explosion＂. To constrain the early cambrian oceanic redox environment, we conducted an integrated study on iron and sulfur isotopes and redox-sensitive elements（Mo, U, and V） of Lower cambrian phosphorite deposits from two shallow sections（Meishucun and Gezhongwu） and a deeper water section（Zunyi） from the Yangtze Platform, South China. The near zero δ^（56）Fe values from the two shallow sections studied here reflect oxic conditions in the lower phosphorite deposition. An obvious positive shift in δ^（56）Fe and redox-sensitive element content was observed in the middle parts of the two shallow water sections, which might reflect loss of light iron by dissimilatory iron reduction during early diagenesis under suboxic shallow water in the platform. However, the highly positive δ^（56）Fe values in the deep section could reflect a lower oxidation degree of dissolved Fe（II） under anoxic deep water. The data suggest redox-stratified oceanic conditions during the early cambrian, in which completely oxygenated shallow water（platform） coexisted with anoxic deep water（slope）. We propose that prolonged upwelling of dissolved organic carbon（DOC）-, Fe（II）- and phosphorus-rich anoxic deep water in a redox-stratified ocean could have increased exchange with the open ocean, resulting in major phosphorite deposition in oxic-suboxic conditions. The progressive oxygenation of the ocean may have facilitated the early cambrian biotic diversification.

关键词： early cambrian redox-stratified ocean southern China iron isotope phosphorite.

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Paleoceanographic Indicators for early cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes

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Acta Geologica Sinica(English Edition) 2012年第5期86卷 1143-1153页

作者： CHEN Lan ZHONG Hong HU Ruizhong XIAO Jiafei TSAI Louis Loung-Yie LIN Andrew Tien-Shun ZOU Yanrong College of Petroleum Engineering Chongqing University of Science and TechnologyChongqing 401331China Institute of Applied Geology National Central UniversityJhongli 32001 Institute of Geophysics National Central UniversityJhongli 32001 State key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyangGuizhou 550002China State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhouGuangdong 510640China

The lower cambrian Niutitang Formation, a widespread black shale deposition, is of geological interest because of its polymetallic beds, cambrian explosion, depositional ages, dramatic environmental changes and so on. Previous study focused mainly on inorganic geochemistry and few studies have investigated the organic fractions of upper Neoproterozoic-lower cambrian strata in South China. Here we report a study of biomarkers plus organic carbon isotopes for black shales from Ganziping, Hunan Province （China）. All the saturated hydrocarbon fractions have a unimodal distribution of n-alkanes, a high content of short-chain alkanes and maximize at C 19 or C 20 （C 23 for sample Gzh00-1）. The C 27 /C 29 sterane ratio ranges from 0.77 to 1.20 and 4-methylsteranes are in low abundance. These parameters indicate that algae and bacteria are the important primary producers. Furthermore, biomarker maturity proxies show the samples to be higher maturity. The low Pr/Ph values （0.7） suggest that the samples were deposited under anoxic conditions and, likely, under stratified water columns. In addition, 25-norhopanes and gammacerane are present as diagnostic indicators of normal marine salinity and dysoxic to anoxic conditions. During the early Tommotian, known to coincide with a transgression event, small shelly fossils increased in abundance and diversity. Moreover, positive δ 13 C org excursions close to 1.4‰ occur at the base of the Tommotian stage. In summary, the early cambrian black shales were deposited under dramatic paleoenvironmental changes, including oceanic anoxia, higher primary productivity and sea-level rise.

关键词： black shales biomarkers carbon isotope paleoceanography early cambrian South China

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