Impact of Marine Redox Conditions on Animal Evolution in Early Cambrian Nanhua Basin,South China
Marine redox variations have been frequently used to explain the radiation and extinction of early animals during the Early Cambrian.However,this hypothesis remains unclear.Here,it conducted total organic carbon,iron speciation,major elements,and trace elements in the basinal Zhalagou Section.The new redox results were compared with published redox environments from the coeval other sections in South China and Siberian.The results suggest that oxic waters were intensively expanded during Cambrian Age 2-3,whereas the degree of oceanic anoxia was enhanced during Cambrian Age 4.Comparison of ocean redox states and fossils suggests that enhanced ocean oxygenation might play key roles in the radiation of early animals during Cambrian Age 2-3,but expanded ocean anoxia might have significant effects on the decreased diversification of early animals and extinction of archaeocyaths during Cambrian Age 4.
iron speciationtrace elementanoxiaanimal extinctionYangtze Blockgeochemistry
万方数据
维普
