Paleo-productivity evolution across the Permian-Triassic boundary and quantitative calculation of primary productivity of black rock series from the Dalong Formation, South China  

作　　者：SHEN Jun ZHOU Lian FENG QingLai ZHANG MuHui LEI Yong ZHANG Ning YU JianXin GU SongZhu 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences [2]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences [3]Faculty of Earth Science, China University of Geosciences

出　　处：《Science China Earth Sciences》2014年第7期1583-1594,共12页中国科学（地球科学英文版）

基　　金：was supported by National Natural Science Foundation of China (Grant Nos. 41073007 and 41273005);National Basic Research Program of China (Grant No. 2011CB808800);the 111 Project (Grant No. B08030);Research Fund for the Doctoral Program of Higher Education (Grant No. 20110145130001);special funding from the State Key Laboratory of Geological Processes and Mineral Resources;a contribution to IGCP Project 572 (Grant No. GPMR201301)

摘　　要：The change of the primary productivity across the Permian-Triassic boundary （PTB） remains controversial. In this study, records from two deep-water sections in South China （Xiakou and Xinmin sections） show the primary productivity decreased gradually from the latest Permian to the earliest Triassic, and five evolutionary stages Increase-Decrease-Recovery-Recession- Stagnation） can be observed from Clarkina changxingensis-C, deflecta to Hindeodus parvus-lsarcicella isarcica zones. Pri- mary productivity decreased abruptly from the base of C. meishanensis zone. Besides, for adjusting to the deterioration of the oceanic environment, the primary producers in the oceanic surface had changed to acritarch and cyanobacteria, which were more tolerant of stressful environment. Then the producers were under huge stagnation in the H. parvus-L isarcica zone. The values of quantitative calculation of the primary productivity from the black rock series in the Dalong Formation were very high, corresponding to that of an upwelling area in modern ocean, which shows that the strata of the Dalong Formation in the study region are potential hydrocarbon source-rocks. This result may come from the fact that South China craton was located at the equatorial upwelling area during the Permian-Triassic transitions. But organic matter contents were different in various sections because they could be affected by redox conditions and diagenesis process after burial.The change of the primary productivity across the Permian-Triassic boundary(PTB)remains controversial.In this study,records from two deep-water sections in South China(Xiakou and Xinmin sections)show the primary productivity decreased gradually from the latest Permian to the earliest Triassic,and five evolutionary stages Increase-Decrease-Recovery-RecessionStagnation)can be observed from Clarkina changxingensis-C.deflecta to Hindeodus parvus-Isarcicella isarcica zones.Primary productivity decreased abruptly from the base of C.meishanensis zone.Besides,for adjusting to the deterioration of the oceanic environment,the primary producers in the oceanic surface had changed to acritarch and cyanobacteria,which were more tolerant of stressful environment.Then the producers were under huge stagnation in the H.parvus-I.isarcica zone.The values of quantitative calculation of the primary productivity from the black rock series in the Dalong Formation were very high,corresponding to that of an upwelling area in modern ocean,which shows that the strata of the Dalong Formation in the study region are potential hydrocarbon source-rocks.This result may come from the fact that South China craton was located at the equatorial upwelling area during the Permian-Triassic transitions.But organic matter contents were different in various sections because they could be affected by redox conditions and diagenesis process after burial.

关 键 词：paleo-productivity black rock series hydrocarbon source rock Dalong Formation redox condition geochemical proxy 

分 类 号：Q911[天文地球—古生物学与地层学]