摘要
新元古代的冰期事件一直是地质界研究的热点之一。包括中国在内 ,世界许多地区新元古代地层中普遍发育有一至两层冰碛岩 ,有的地区甚至可以见到三层冰碛岩 ,在冰碛岩之上往往有碳酸盐岩盖层 ( Cap Carbonate)。通过对皖南休宁新元古代冰碛岩的岩石地层学 ,以及碳、氧稳定同位素化学地层学的研究 ,证实了休宁新元古代地层存在两期冰川的记录 ,并通过与国内外同时代典型地层剖面的对比 ,认为休宁蓝田剖面的两层冰碛岩可能分别相当于 Sturtian冰期和 Marinoan冰期的沉积 ,其时代分别约为 710— 73 0 Ma,5 90— 60 0
The Neoproterozoic Glaciation (known as “Snowball Earth”) is one of the remarkable events in Earth history. In this paper, the late Neoproterozoic tillites at Lantian, Xiuning, South Anhui have been studied in detail by means of stratigraphy and chemostratigraphy. Lithologically, the Leigongwu Formation can be divided into 3 units: the upper diamictite, the middle dolomite and black shales and the lower diamictite. Comparison of C-isotope results of the cap dolomites, which are about -5‰ (PDB), with δ 13C profiles of contemporaneous carbonates around the world suggests that the two tillites of the Leigongwu Formation may represent two glaciations and correspond to the Sturtian (710—730Ma) and Marinoan (590—600Ma) tillites, respectively.
出处
《地层学杂志》
CSCD
北大核心
2001年第4期247-252,258,共7页
Journal of Stratigraphy
基金
国家重点基础研究发展规划项目( G2 0 0 0 0 7770 0 )
国家自然科学基金委员会青年基金 ( No.4990 2 0 0 2 )
中国科学院创新基金
江苏省自然科学基金的资助
