Benthic macro red alga:A new possible bio-precursor of Jurassic mudstone source rocks in the northern Qaidam Basin,northwestern China  

作　　者：CAO Jian BIAN LiZeng HU Kai LIU YunTian WANG LiQun YANG ShaoYong CHEN Yan PENG XiaoQun 

机构地区：[1]State Key Laboratory for Mineral Deposits Research,Department of Earth Sciences,Nanjing University,Nanjing 210093,China [2]PetroChina Qinghai Oilfield Company,Dunhuang 736202,China

出　　处：《Science China Earth Sciences》2009年第5期647-654,共8页中国科学（地球科学英文版）

基　　金：Supported by National Natural Science Foundation of China (Grant Nos. 40602014, 40872086, 40638042)

摘　　要：Whether benthic macroalga can be an important type of bio-precursor of source rocks is a contentious issue in source-rock studies,and has not been well understood.This paper represents a case study of Jurassic mudstone source rocks from the northern Qaidam Basin,northwestern China,in which the benthic macro red algae were recognized for the first time based on combined organic petrological and biomarker works.We found not only cystocarps in the algae,representative of rhodophyta,but also diahopanes,which are diagnostic biomarkers of such algae.Thus,as many reservoired oils in the northern Qaidam Basin contain abundant diahopanes,it may indicate that the red algae have contributed to hydrocarbon accumulation.This was confirmed by integrated geological and geochemical analyses.Hence,this study provides new evidence for macroalga-generated hydrocarbons.Whether benthic macroalga can be an important type of bio-precursor of source rocks is a contentious issue in source-rock studies, and has not been well understood. This paper represents a case study of Jurassic mudstone source rocks from the northern Qaidam Basin, northwestern China, in which the benthic macro red algae were recognized for the first time based on combined organic petrological and biomarker works. We found not only cystocarps in the algae, representative of rhodophyta, but also diahopanes, which are diagnostic biomarkers of such algae. Thus, as many reservoired oils in the northern Qaidam Basin contain abundant diahopanes, it may indicate that the red algae have contributed to hydrocarbon accumulation. This was confirmed by integrated geological and geochemical analyses. Hence, this study provides new evidence for macroalga-generated hydrocarbons.

关 键 词：bioprecursor of source rock BENTHIC MACRO red alga(rhodophyta) 17α(H)-C30 diahopane JURASSIC the northern Qaidam Basin 

分 类 号：P618.13[天文地球—矿床学]