中国地质2013，Vol.40Issue(4)：1099-1111,13.
四川盆地晚震旦世古海洋环境恢复及地质意义
Reconstruction of the late Sinian paleo-ocean environment in Sichuan basin and its geological significance
摘要
Abstract
On the basis of carbon and oxygen isotopic compositions of 69 dolomite samples collected from three sampling points of the Sinian Dengying Formation in Sichuan basin and the effectiveness evaluation of the data,the authors studied the changing characteristics of carbon and oxygen isotopes with the purpose of further reconstructing the corresponding paleo-ocean environment and investigating its geological meaning.The δ13Cvalues of dolomite in Dengying Formation vary from-2.85‰ to 4.44‰ with a mean value of 1.80‰ and the δ13Cvaries vary between-9.02‰ and-1.90‰,-5.42‰ on average.The changing trends of the carbon and oxygen isotopes are similar to those in other strata of the same period in the Yangtze platform.Through the reconstruction of paleo-ocean environment,the authors found that the Sichuan basin of Late Sinian Dengying period was in a marine environment,and the seawater temperatures varied mainly between 15℃ and 30℃,suggesting a warm or hot subtropical climate.The sea level experienced six stages in Dengying period in the study area,i.e.,slow transgression,lowstand oscillatory regression,highstand oscillatory regression,transient transgression,sustained regression and oscillatory regression.Under the influence of sea level fluctuation,climate change,tectonic movement and volcanic activity,four negative δ13C anomalies (N1～N4) and two positive δ13Canomalies (P1～P2) occurred in dolomite of Dengying Formation.The basin was filled with easily-recognized grape-sized algal dolomite in Deng2 Member,dark clastic rock in Deng3 Member and algal dolomite in Deng4 Member because of the influence of the paleo-ocean environment.关键词
碳氧同位素/古海洋环境/地质意义/灯影组/晚震旦世/四川盆地Key words
carbon and oxygen isotopes/paleo-ocean environment/ geological significance /Dengying Formation/Late Sinian/ Sichuan basin分类
海洋科学引用本文复制引用
罗贝维,魏国齐,杨威,董才源..四川盆地晚震旦世古海洋环境恢复及地质意义[J].中国地质,2013,40(4):1099-1111,13.基金项目
国家科技重大专项(2011ZX05007-002)资助. （2011ZX05007-002）
