Occurrence of Organic Matter in Calcimicrobialites across Permian-Triassic Boundary in Huayingshan Region,Sichuan,South China  

作　　者：杨浩 王永标 陈林 

机构地区：[1]Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences,Wuhan 430074, China [2]Faculty of Earth Sciences, China University of Geosciences,Wuhan 430074, China

出　　处：《Journal of China University of Geosciences》2008年第5期518-525,共8页中国地质大学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 40730209, 40572002);the 111 Project (B08030);the SINOPEC project (G0800-06-ZS-319)

摘　　要：Calcimicrobialites across the Permian-Triassic boundary in Huayingshan （华蓥山） region were investigated using the fluorescence microscopic measurements to understand the occurrence of organic matter. The microbialites are composed of micrite matrix and coarse spar cement. Abundant rhombic or magnetic needle-like carbonate minerals were observed adrift within the cement. The fluorescence microscopic measurement indicates the micrite matrix in microbialites shows the most abundant organic matter, with the rhombic or magnetic needle-like carbonate minerals and coarse spar cement coming to the 2nd and the 3rd, respectively. Organic matter is mainly preserved in the space between the grains of the micrite minerals but almost evenly distributed in the rhombic or magnetic needle-like carbonate minerals. As one of the common diagenesis types, dolomitization is observed to occur in the microbialites in Huayingshan. However, the carbonate cement in microbialites still has high content of element Sr as shown by the microprobe analysis, reflecting that the dolomitization might have happened in a restricted environment. Observation under the fluorescence microscope shows that dolomitization just led to the redistribution of organic matter in the grain space of dolomite minerals, inferring that the diagenesis has a slight effect on the preservation, and thus on the content of organic matter in the microbialites.Calcimicrobialites across the Permian-Triassic boundary in Huayingshan （华蓥山） region were investigated using the fluorescence microscopic measurements to understand the occurrence of organic matter. The microbialites are composed of micrite matrix and coarse spar cement. Abundant rhombic or magnetic needle-like carbonate minerals were observed adrift within the cement. The fluorescence microscopic measurement indicates the micrite matrix in microbialites shows the most abundant organic matter, with the rhombic or magnetic needle-like carbonate minerals and coarse spar cement coming to the 2nd and the 3rd, respectively. Organic matter is mainly preserved in the space between the grains of the micrite minerals but almost evenly distributed in the rhombic or magnetic needle-like carbonate minerals. As one of the common diagenesis types, dolomitization is observed to occur in the microbialites in Huayingshan. However, the carbonate cement in microbialites still has high content of element Sr as shown by the microprobe analysis, reflecting that the dolomitization might have happened in a restricted environment. Observation under the fluorescence microscope shows that dolomitization just led to the redistribution of organic matter in the grain space of dolomite minerals, inferring that the diagenesis has a slight effect on the preservation, and thus on the content of organic matter in the microbialites.

关 键 词：organic matter calcimicrobialite PERMIAN-TRIASSIC fluorescence Huayingshan. 

分 类 号：Q911[天文地球—古生物学与地层学]