南京孔山剖面早二叠世冰川旋回期内氧碳同位素演化特征及其环境意义

CHARACTERISTIC OF OXYGEN CARBON ISOTOPES AND ITS ENVIRON MENTAL SIGNIFICANCE OF LOWER PERMIAN CARBONATE ROCK IN KONGSHAN SECTION,NANJING,JIANGSU

在南京孔山地区早二叠世的碳酸盐岩沉积序列中系统地采集了样品并进行了氧、碳同位素分析 ,同时作了有关海平面变化的研究。结果表明 ,处于浅水和近岸环境的碳酸盐岩的氧同位素值系“全球冰川效应”和区域的淡水掺混两种作用相互平衡的结果。它的变化特征虽然可以忠实地记录原生沉积环境的变迁 ,但不能简单套用远洋沉积物中所总结出的模式。碳同位素亦非古代海平面变化的简单函数。有机碳埋藏速率及与之相关的氧化 -还原环境应是 δ1 3

Taken from Nanjing Kongshan section in series,samples of Lower Permian carbonate rock are studied isotopically in this paper.Researches,are related with sea level change,are also completed by studying the variation of oxygen carbon isotopes of the section.The result shows that value of oxygen isotope is controlled mainly by the balance between “Global Ice Effect” and regional mixed freshwater effect in seashore.Although the characteristic of oxygen isotope can not be illustrated by an extant model designed for pelagic sediment,it can reflect the change of original environment faithfully.Value of carbon isotope is not a linear function of ancient sea level change.The most important factors,which control the values of carbon isotope,are the embedding velocity of organic carbon and relative environment of reduction oxidation.