Characteristics of sulfur species and their implications in Lower Cambrian black shales from southern margin of Yangtze Platform

【作者】 雷加锦； 李任伟； H.J.Tobschall； 濮英英； 方家虎；

【Author】 LEI Jiajin LI Renwei H.J.Tobschall PU Yingying FANG Jiahu 1.Institute of Geology,Chinese Academy of Sciences,Beijing 100029,China; 2.Institute of Geology and Mineralogy,University of Eriangen-Nuremberg,D-91054 Erlangen,Germany; 3.China University of Mining and Technology,Beijing 100083,China

【机构】 Institute of Geology,Chinese Academy of Sciences； Institute of Geology and Mineralogy,University of Erlangen-Nuremberg； China University of Mining and Technology；

【摘要】 <正>There are different sulfur forms in the black shales from the Early Cambrian of the Yangtze platform.With its emphasis on pyrite and organosuifur,this paper discusses their distribution and formation.The research shows that sulfur phases take regular variations laterally as well as vertically in the research areas.In western researched profile with high terrigenous supply at the time it formed,there exists a larger amount of pyrite and less organosulfur,and pyrite amount declines while organosuifur content increases upwards along the profile.This black shale profile is characterized by relatively light sulfur isotope composition with evolution trend of becoming heavier both for pyrite and organosulfur from bottom to top along the profile.Opposite situation occurs in eastern profiles which were located farther away from terrigenous land.Here pyrite amount obviously decreases and organic matter has combined more sulfur,although these two kinds of sulfur species take similar trend in content variation along profiles to that for western profile.At the same time more ³⁴S is accumulated in sulfur species of black shale samples from eastern profile,and sulfur isotope composition gradually turns lighter from bottom to top.In combination with other information of iron,organic carbon contents and petrographic features,it can be established that sea-level change,supply of terrigenous matters,tectonic background and natures of paleoceanic chemistry have exerted great influence on the distribution of sulfur species in these black shales.更多还原

【Abstract】 There are different sulfur forms in the black shales from the Early Cambrian of the Yangtze platform.With its emphasis on pyrite and organosuifur,this paper discusses their distribution and formation.The research shows that sulfur phases take regular variations laterally as well as vertically in the research areas.In western researched profile with high terrigenous supply at the time it formed,there exists a larger amount of pyrite and less organosulfur,and pyrite amount declines while organosuifur content increases upwards along the profile.This black shale profile is characterized by relatively light sulfur isotope composition with evolution trend of becoming heavier both for pyrite and organosulfur from bottom to top along the profile.Opposite situation occurs in eastern profiles which were located farther away from terrigenous land.Here pyrite amount obviously decreases and organic matter has combined more sulfur,although these two kinds of sulfur species take similar trend in content variation along profiles to that for western profile.At the same time more ³⁴S is accumulated in sulfur species of black shale samples from eastern profile,and sulfur isotope composition gradually turns lighter from bottom to top.In combination with other information of iron,organic carbon contents and petrographic features,it can be established that sea-level change,supply of terrigenous matters,tectonic background and natures of paleoceanic chemistry have exerted great influence on the distribution of sulfur species in these black shales.更多还原