• 责任者：Ma Zhongwu (Key Laboratory of Biogeology and Environmental Geology of Ministry of Education ; China University of Geosciences ; Wuhan 430074 ; China) ; Hu Chaoyong
• 刊名：Journal of China University of Geosciences
• 出版年：2008
• 卷期：19(5)
• 关键词：Permian ; paleoproductivity ; trace element ; hydrocarbon source rock
• 页码：p.461–470
• 图表：4 illus., 1 table, 41 refs.
• issnNo：ISSN1002-0705
• isbnNo：CN42-1279/P

The   marine   primary   producers   assimilate   the   atmospheric   CO₂        to   form   the   organic carbon   in   surface   water.   The   organic   carbon   then   settles   down   through   the   water   column   and   is  removed from the oceans by final preservation in sediments in the form of petroleum or nature gases. The    reconstruction    of  paleoproductivity    will thus    improve    our  understanding     of  the  biological processes in the formation of fossil energy resource and help to locate new sites for future exploration. In this study, biorelated elements P, Cd, Al, Ba, as well as redox sensitive element Mo, were analyzed in the 448 rock samples collected from Permian strata at the Shangsi Section, Guangyuan, Northeast Sichuan  in China. On the basis of the Ti content, the nondetrital contents of P, Ca, and   Al,   denoted   as   Pxs,   Cdxs,   and   Alxs,   were   calculated   and   found   to   coincide   with   the   TOC   content hroughout the whole section, with some enrichment intervals being found in the middle part of Chihsia Formation, topmost Maokou Formation, and Dalong Formation. This suggests that the biorelated   elements   could   be   used   as   proxies   for   the   paleoproductivity   here   in   this   section.   Baxs,   a paleoproductivity indicator widely used in the paleoceanography, shows insignificant correlation with TOC,   Pxs,   Cdxs,   and   Alxs,   probably   arising   from   the   loss   of   biological   barium   in   anoxic   conditions. Compiled      with  the   data  of  TOC    content   and   Pxs,  Cdxs,  and   Alxs,  three  episodes  of  enhanced paleoproductivity were   identified   in   Permian strata   including   the   middle   part   of   Chihsia Formation, topmost Maokou Formation, and Dalong Formation.