【摘要】 为了探讨塔里木盆地塔中地区寒武系—奥陶系碳酸盐岩碳同位素变化的原因,对取自塔中地区中3、中4、中12和中13等井的49块碳酸盐岩样品进行了分析,结果显示δ13C值的变化曲线与同时期该区海平面的升降变化一致,说明寒武-奥陶系海相碳酸盐岩的碳同位素变化可能与海平面变化有密切联系。在晚寒武世—早奥陶世晚期为一海退期,有机质产率及有机碳埋藏速率的下降导致碳酸盐岩δ13C值的降低;而在早奥陶世晚期—中奥陶世为一海侵期,有机质产率及有机碳埋藏速率的增加导致了碳酸盐岩1δ3C值的增高;晚寒武世—早奥陶世海水中的硫酸盐含量高,硫酸盐细菌的还原作用使有机质氧化,从而导致碳酸盐岩δ13C值降低。更多还原

【Abstract】 In order to discuss variation causes of Late CambrianOrdovician carbonate rock isotope in central Tarim Basin,49 carbonate rock samples obtained from Well Ta 3,4,12 and 13 are analyzed.The results show that,variation curve of δ13C value is same with up and down variation of sea level, hence indicating that its variation is correlated with sea level variation.Late Cambrian-Early Ordovician is in the period of regression,production ratio of organic matter and buried ration of organic matter declined will result in declining of carbonate rock δ13C value,while early Ordovician-middle Ordovician is incursion period,the increasing of them results in the increasing of carbonate rockδ13C value.In addition,sea water contains sulphate with high content in Late Cambrian-Ordovician period.Sulphate bacterium deoxygenation can lead organic matter to oxidate,thereby resulting in declining of carbonate rockδ13C value.更多还原