| 中国南方灯影峡期海洋碳酸盐岩原始δ13C和δ18O组成及海水温度 |
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| 引用本文： | 黄志诚 陈智娜 杨守业 刘,燕.中国南方灯影峡期海洋碳酸盐岩原始δ13C和δ18O组成及海水温度[J].古地理学报,1999,1(3):1-07. |
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| 作者姓名： | 黄志诚 陈智娜 杨守业 刘 燕 |
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| 作者单位： | 1.南京大学地球科学系和成矿作用国家重点实验室，南京 210093;2.同济大学海洋地质系，上海 200092 |
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| 基金项目： | 国家自然科学基金资助项目，编号49372118 |
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| 摘 要： | 中国南方灯影峡期(晚前寒武纪)是白云岩广泛发育的海洋碳酸盐沉积时期，在灯影组中部发育从海水直接沉积沉淀的原生白云岩，目前仍保留其原始组构特征。从40个原生白云石(岩)中测得:泥晶白云石的δ13C值为3.64‰,δ18O值为-1.17‰(n=6);白云岩的13C值为3.52‰，δ18O值为-1.86‰(n=15);海水纤状白云石胶结物δ13C值为2.90‰，δ18O值2.65‰(n=8)；海水刃状白云石胶结物的δ13C值为2.96‰,δ18O值为-2.41‰(n=8);晶纹层和海水纤状白云石胶结物的δ13C值为2.79‰，δ18O值为-3.13‰。40个岩样的δ13C平均值为3.25‰±0.44‰,δ18O平均值为-2.12‰±0.98‰(均以PDB标准)。对于灯影峡期海相云岩的原始δ13C和δ18O值，不采用所有样品的平均值，而是采用原生白云石沉积物与海水白云石结物δ13C值和δ18O值两个图示分布区重叠部分的最重同位素值，即：δ1C值为4.43‰(PDB标准),δ18O值为-0.62‰(PDB标准),将其作为灯影峡期海洋碳酸盐岩的原始同位素组成。对海水原生白云石胶结物包裹体盐度进行了测定，海水δ18O计算值为2.90(SMOW标准)，用原始δ18O值计算的原生白云石形成时的海水温度为40.8 ℃。这说明中国南方灯影峡的海洋为炎热的较高的海水温度环境。
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PRIMARY 13C AND 18O VALUES IN MARINECARBONATES AND THE SEA WATER TEMPERATURE |
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| Huang Zhicheng Chen Zhina Yang Shouye,Liu Yan.PRIMARY 13C AND 18O VALUES IN MARINECARBONATES AND THE SEA WATER TEMPERATURE[J].Journal of Palaeogeography,1999,1(3):1-07. |
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| Authors: | Huang Zhicheng Chen Zhina Yang Shouye Liu Yan |
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| Institution: | 1.Department of Earth Sciences and Laboratory of Mineralizing Processes of Ore Deposits,Nanjing University, Nanjing210093;2.Department of Marine Geology, Tongji University, Shanghai 200092 |
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| Abstract: | The Dengyingxia Stage (Late Precambrian) in South China is a marine carbonate sedimentary stage with extensively developed dolostones. The primary dolostones precipitated directly from sea water are developed in the middle unit of Dengying Formation and their primary texture are reserved well. The δ13C and δ18O values have been determined from 40 samples of primary dolomites (dolostones): 13C=3.64‰ and δ18O=-1.17‰ (n=6) for micrite dolomites; δ13C=3.52‰ and δ18O=-1.86‰ (n=15) for algae dolostones; δ13C=2.90‰ and δ18O=-2.65‰ (n=8) for fibrous dolomite cements; δ13C=2.96‰ and δ18O=-2.41‰ (n=8) for bladed dolomite cements; δ13C=2.79‰ and δ18O=-3.13‰ (n=3) for micrite lamella and fibrous dolomite cements. The average δ13C and δ18O values of all 40 samples are 3.25‰±0.44‰ and -2.12‰±0.98‰ respectively (PDB standard). The heaviest δ13C and δ18O values in overlap ping area of the values of the primary dolomite sediments and the cements in diagram, δ13C=4.43‰ JP](PDB) and δ18O=-0.62‰ (PDB), has been determined as the primary carbon and oxygen isotope composition of the Dengyingxia marine carbonate. The δ18O value of sea water of Dengyingxia Age is 2.90‰(SMOW) calculated based on the salinity of the inclusion in primary dolomite cement. The temperature of sea water at that time is 40.8 ℃ calculated on the basis of the primary δ18O value. It indicates that hot climate and high temperature existed in Dengyingxia Age in South China. |
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