Microbial and molecular fossils from the Permian Zoophycos in South China  

作　　者：GONG YiMing XU Ran XIE ShuCheng HUANG XianYu HU Bin QI YongAn ZHANG GuoCheng 

机构地区：[1]Key Laboratory of Biogeology and Environmental Geology of Ministry of Education,State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China [2]Institute of Resources and Environment,Key Laboratory of Biogenic Traces&Sedimentary Minerals of Henan Province,Henan Polytechnic University,Jiaozuo 454003,China

出　　处：《Science China Earth Sciences》2007年第8期1121-1127,共7页中国科学（地球科学英文版）

基　　金：the Special Project of Basic Research of China (Grant No. 2005CCA05000);the National Natural Science Foundation of China (Grant Nos. 40472020, 40621002 and 40525008);the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 2004000127) ;other projects (Grant Nos. IRT0546 and G0800-06-ZS-319)

摘　　要：The trace fossil Zoophycos was enriched in the lower part of the Guadalupian Maokou Formation of Permian in Laibin, Guangxi of South China, and characterized by observable lamellae within its spreiten. Associated with these lamellae are the prolific coccus- and spirillum-shaped microbe fossils. These microbes morphologically identified are 0.4―3.0 μm in diameter or length. Molecular fossils, including normal alkanes (dominated by C18, without an odd-over-even predominance), acyclic isoprenoids (such as pristane (Pr) and phytane (Ph)), extended tricyclic terpanes, pentacyclic triterpanes, steranes, al-kylcyclohexanes, dibenzothiophenes, benzonaphthothiophenes, benzobisbenzothiophenes, were in-strumentally identified in the wackestone characterized by the occurrence of abundant Zoophycos (composite ichnofabric indices are 4) and crowded microbial fossils. The value of the Pr/Ph ratio is less than 1, indicative of a dysoxic condition. The identification of abundant sulfur compounds (the thio-phene series) related to the contribution of reductive sulfur favors the occurrence of sulphate-reducing bacteria. The association of abundant microbial colonies with microbial molecular fossils within the spreiten suggests that trace fossils Zoophycos would be a multifunctional garden carefully constructed by the Zoophycos-producer, where different microbial colonies were orderly and carefully planted and cultured in different minor lamellae within spreiten. Hence, it is proposed that the Zoophycos-producer symbiosed with microbial colonies on the mutual basis of food supply and the redox conditions.The trace fossil Zoophycos was enriched in the lower part of the Guadalupian Maokou Formation of Permian in Laibin, Guangxi of South China, and characterized by observable lamellae within its spreiten. Associated with these lamellae are the prolific coccus- and spirillum-shaped microbe fossils. These microbes morphologically identified are 0.4–3.0 μm in diameter or length. Molecular fossils, including normal alkanes (dominated by C18, without an odd-over-even predominance), acyclic isoprenoids (such as pristane (Pr) and phytane (Ph)), extended tricyclic terpanes, pentacyclic triterpanes, steranes, alkylcyclohexanes, dibenzothiophenes, benzonaphthothiophenes, benzobisbenzothiophenes, were instrumentally identified in the wackestone characterized by the occurrence of abundant Zoophycos (composite ichnofabric indices are 4) and crowded microbial fossils. The value of the Pr/Ph ratio is less than 1, indicative of a dysoxic condition. The identification of abundant sulfur compounds (the thiophene series) related to the contribution of reductive sulfur favors the occurrence of sulphate-reducing bacteria. The association of abundant microbial colonies with microbial molecular fossils within the spreiten suggests that trace fossils Zoophycos would be a multifunctional garden carefully constructed by the Zoophycos-producer, where different microbial colonies were orderly and carefully planted and cultured in different minor lamellae within spreiten. Hence, it is proposed that the Zoophycos-producer symbiosed with microbial colonies on the mutual basis of food supply and the redox conditions.

关 键 词：TRACE FOSSILS ZOOPHYCOS microbes molecular FOSSILS PERMIAN South China 

分 类 号：Q913[天文地球—古生物学与地层学]