Biomarker geochemistry of marine organic matter in the Hushan and Chaohu areas,Lower Yangtze region  

作　　者：Chang, Chao  Wang, Shaohua  Zhu, Chen  Ma, Weimeng  Hu, Wenxuan  Cao, Jian 

机构地区：[1] State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China [2] Key Laboratory of Tectonics and Petroleum Resources [China University of Geosciences], Ministry of Education, Wuhan 430074, China

出　　处：《Chinese Journal Of Geochemistry》2011年第2期145-152,共8页中国地球化学学报

基　　金：funded by the National Natural Science Foundation of China (Grant Nos. 41072090 and 40872086);the Undergraduate Innovation Program of Nanjing University;the Open Project Program of Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education (Grant No. TPR-2010-26)

摘　　要：Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of representative samples collected from the Silurian, Carboniferous and Triassic systems and their geological implications, thus providing clues to marine organic matter. On the basis of experimental results, it is shown that abundant biomarkers (e.g. n-alkanes, isoprenoids, terpanes and steranes) were detected. As organic matter in the strata is highly to over mature in general based on petrologic microobservation, some biomarkers (mainly n-alkanes) except terpanes and steranes cannot reflect the source, depositional environment and maturity of organic matter. Thus, primarily based on analyses of the terpanes and steranes, it is suggested that organic matter in the Silurian and Carboniferous strata is derived mainly from lower organisms, while higher plants are predominant in the Triassic organic matter. This further indicates that the depositional environment may have transformed from the marine to continental facies in the Late Triassic. These results provide new evidence for the study of regional depositional evolution, and have enriched the study of biological composition of organic matter. In addition, the biomarker geochemistry of organic matter at high to over maturation stage is addressed.Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of representative samples collected from the Silurian, Carboniferous and Triassic systems and their geological implications, thus providing clues to marine organic matter. On the basis of experimental results, it is shown that abundant biomarkers (e.g. n-alkanes, isoprenoids, terpanes and steranes) were detected. As organic matter in the strata is highly to over mature in general based on petrologic microobservation, some biomarkers (mainly n-alkanes) except terpanes and steranes cannot reflect the source, depositional environment and maturity of organic matter. Thus, primarily based on analyses of the terpanes and steranes, it is suggested that organic matter in the Silurian and Carboniferous strata is derived mainly from lower organisms, while higher plants are predominant in the Triassic organic matter. This further indicates that the depositional environment may have transformed from the marine to continental facies in the Late Triassic. These results provide new evidence for the study of regional depositional evolution, and have enriched the study of biological composition of organic matter. In addition, the biomarker geochemistry of organic matter at high to over maturation stage is addressed.

关 键 词：Lower Yangtze region Hushan area Chaohu area organic matter BIOMARKER depositional environment marine facies high to over maturation 

分 类 号：P59[天文地球—地球化学]