末元古系—寒武系底Sr、C同位素对比  

Strontium and Carbon Isotopic Calibration of the Terminal Proterozoic

作　　者：杨杰东[1,2] 张俊明[3] 陶仙聪 王宗哲[3] 

机构地区：[1]南京大学现代分析中心,江苏南京210093 [2]南京大学成矿机制研究国家重点实验室,江苏南京210008 [3]中国科学院南京地质古生物研究所

出　　处：《高校地质学报》2000年第4期532-545,共14页Geological Journal of China Universities

基　　金：国家自然科学基金项目(49873004)资助

摘　　要：测定了云南永善肖滩前寒武系—寒武系界限Sr同位素组成及湖北省三峡剖面震旦系碳酸盐岩Sr、C同位素组成 ,并与蒙古、加拿大、西伯利亚和纳米比亚的末元古系Sr和C同位素数据进行了比较 ,得出末元古纪海水87Sr/ 86Sr和δ13C值的演变图。通过该演变图 。Sr isotopes of limestones for the Precambrian Cambrian boundary from the Xiaotan section, Yongshan, Yunnan province, and Sr and C isotopes of carbonates for the Sinian System from the Sanxia section, Hubei province have been investigated. The results were compared with the Sr and C isotopic data derived from Mongolia, Canada, Siberia and Namibia. A variation curve of 87 Sr/ 86 Sr and δ 13 C for the seawater of the terminal Proterozoic was proposed. Just before the terminal Proterozoic, the δ 13 C value of seawater was high, about +11‰, and the 87 Sr/ 86 Sr was about 0.7072. At the period of glaciation corresponding to the Nantuo/Ice Brook, the δ 13 C value of seawater was negative, about -5‰, and the 87 Sr/ 86 Sr was about 0.7077. Later on, the δ 13 C value rapidly rose with at least three fluctuations. At the time corresponding to the Dengying formation, the δ 13 C value showed a flat terrace about +2～+3‰, and the 87 Sr/ 86 Sr about 0.7084. At the Precambrian Cambrian boundary, the δ 13 C value rapidly rose from a negative value to about +6‰, and the 87 Sr/ 86 Sr kept at about 0.7084. From the variation curve of 87 Sr/ 86 Sr and δ 13 C for seawater proposed in the present study, the strata of the terminal Proterozoic in the world can be correlated with each other.

关 键 词：Sr和C同位素 全球地层对比 末元古系 前寒武系-寒武系界限 

分 类 号：P534.3[天文地球—古生物学与地层学] P597.2[天文地球—地质学]