华南二叠系长兴阶层型剖面碳酸盐岩的碳氧同位素地层

Carbon and Oxygen Isotope Stratigraphy of the Upper Permian Changhsingian Limestone in Meishan Section D,Changxing,Zhejiang

华南长兴阶层型剖面４０多米厚的地层主要由泥晶灰岩组成，从中系统采集了１５９个碳酸盐岩样品进行碳氧同位素地层学研究，清楚地识别出同位素的变化规律，划分出８个序列和３个旋回。３个碳氧同位素地层旋回由上至下为：长兴早期的Ｐａｌａｅｏｆｕｓｕｌｉｎａｍｉｎｉｍａ旋回，长兴中期的Ｃｒｕ－ｒｉｔｈｙｒｉｓ－Ｇｅｉｎｉｔｚｉｎａ－Ｃｌａｒｋｉｎａｓｕｂｃａｒｉｎａｔａ旋回，长兴晚期的Ｐａｌａｅｏｆｕｓｕｌｉｎａｓｉｎｅｎｓｉｓ旋回。碳酸盐岩碳同位素的异常变化与有机碳的贮藏和氧化相关，而这些变化可能具同时性，记录于整个古华南海水中，从而成为地层对比的良好标志。长兴阶高分辨率碳氧同位素地层的建立，提高了地层的划分精度，为长兴阶进一步的精细地层对比提供了可能。

The Changhsingian limestone is Meishan section D consists mainly of up to 40m of micrites.Based on systematic analyses of 159 pairs of δ 13 C and δ 18 O values in the limestone,three cycles with 8 units of carbon and oxygen isotope stratigraphy are recongnized in the Meishan section D.These three cycles are ascendingly: Palaeofusulina minima cycle (the lower Changhsingian), Crurithyris Geinitzina Clarkina subcarinata cycle (the middle Changhsingian) and Palaeofusulina sinensis cycle (the upper Changhsingian).The isotope shifts of δ 13 C carb due to excess of storage organic carbon (spike) are expected to be found in all marine water at approximately the same intensity,therefore,such detailed isotope cyclostratigraphy is a useful tool for high resolution stratigraphic correlations of the Changhsingian in South China.