%0 Journal Article
%T Petrologic evidence for sea-level drop in latest Permian in Jiangxi province, China and its meanings for the mass extinction<br>江西修水二叠纪·三叠纪界线地层海平面下降的岩石学证据
%A WU YaSheng
%A YANG Wan
%A JIANG HongXi
%A FAN JiaSong
%A <br>吴亚生
%A YANG
%A Wan
%A 姜红霞
%A 范嘉松
%J 岩石学报
%D 2006
%I 
%X A new-found Permian-Triassic boundary section in Xiushui,Jiangxi Province,China shows evidence for sea-level drop during the latest Permian.Evidence for sea-level drop was preserved in a 2.1 m thick interval of limestone,and is 1 m from the P-T boundary.The basal 0.1 m of this interval is a reddish sparry-cemented grainstone.The grains are rounded,dolomitized,all having a black coating.Microprobe analysis indicates that the coating is limonite,which indicates a weathering event in subaerial environments after a sea-level drop event.The internal structure of most grains has been destroyed by diagenesis.Some remained structures of foraminifers and fusulinids.So,this bed is formed before the mass extinction.The 2.0 m thick bed overlying the reddish grainstone is a dedolomitized limestone.The shapes of some original finely-crystalline dolomite rhombus were preserved.The occurrence of dedolomitization is generally related to meteoric water.So,this bed recorded a sea-level drop event.Fossils in this bed are simple: fusulinids and large foraminifers such as Colaniella are absent.It is clear that mass extinction began before this bed.The 1 m thick limestone between the dedolomitized bed and the P-T boundary is composed of grainstone and lime mudstone.Study of this section reached two points:(1)sea-level drop occurred in latest Permian;(2)The end-Permian mass extinction began in the earliest episode of the sea-level drop event.Thus,we cannot exclude the possibility that the mass extinction was caused by a dramatic environmental change which triggered the end-Permian sea-level drop.
%K Mass extinction
%K Permian-Triassic boundary
%K End-Permian
%K Sea-level drop
%K Dedolomitization<br>二叠纪-三叠纪界线地层
%K 二叠纪末
%K 集群绝灭
%K 海平面下降
%K 去白云石化
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=2013B5467E3054B1614CEC199353FCED&aid=23F2F1B2CB9D1CB5&yid=37904DC365DD7266&vid=BC12EA701C895178&iid=59906B3B2830C2C5&sid=1800F07E94FDC0C5&eid=7E58A384CB2431D7&journal_id=1000-0569&journal_name=岩石学报&referenced_num=5&reference_num=57