浙江江山灯影组碳、氧同位素特征

Carbon and oxygen isotope characteristics of Dengying Formation in Jiangshan, Zhejiang Province

通过测试分析了浙江江山灯影组碳酸盐岩的碳、氧同位素特征,结果显示δ13C值在-2.11‰~2.71‰之间,底、顶部表现为负异常,主体部分比较平稳,变化频率不大,呈微弱的降低趋势;δ18O值在-3.52‰^-8.76‰之间变化,整体比较平稳,从底到顶呈略降低的变化趋势。浙江江山碳、氧同位素的特征与国内外同期地层非常相似,具有全球可对比性,反映浙江江山地区在灯影初期海平面短暂下降,随后海洋环境相对稳定,直到灯影末期,与全球古环境发生强烈变化一样,本区海洋环境也发生了强烈变化。

This paper has discussed composition characteristics and variation tendency of carbon and oxygen isotopes from carbonates in Dengying Formation. The ^δ13C values of the carbonates are between - 2. 119‰ and 2.71‰, and negative anomalies are existent at the top and the bottom whereas the main part is relatively stable, with an insignificant decreasing tendency. The δ^18O values are between - 3.52‰ and - 8.76‰, being relatively stable on the whole with a slight decreasing tendency from bottom to top. The composition characteristics and variation tendency are similar to those of the strata of the corresponding period in the world and hence have worldwide correlation significance. The variations of the isotopic content show that the sea level got lowered for a short span at the early stage of Dengying period and then became steady. At the end of Dengying period, the ocean environment in Jiangshan changed intensely, similar to things of the global paleoenvironment in the corresponding period.