沉积与特提斯地质2018，Vol.38Issue(2)：14-22,9.
羌塘盆地东部石炭系杂多群分子地球化学特征及地质意义
Molecular geochemistry and geological significance of the Lower Carboniferous Zaduo Group in Eastern Qiangtang Basin,Xizang
摘要
Abstract
Based on gas chromatography mass spectrometry (GC-MS)techniques,the authors in this paper give a detailed study of molecular fossils characteristics of the source rocks from the Carboniferous Zaduo Group in eastern Qiangtang Basin. The analytical results indicate that the n-alkanes in the Zaduo Group source rocks are composed of nC13-nC35,with nC23 as the main peaks,and characteristic of single peak distribution. The nC21-/nC22+ values range from 0. 22 to 0. 74. The regular steranes have the predominance of C29,and few have the predominance of C27. In the C27-C28-C29 diagram, most of them are mainly located in the mixed source area. The 1-methylphenanthrene/9-methylphenanthrene ratios range from 0. 77 to 9. 95,and 1,7-dimethylphenanthrene is also detected,which are associated with higher plants,indicating a predominant source of organic matter derived from terrigenous higher plants. However lower aquatic organisms have also contributed to hydrocarbon parent material. The Pr/Ph ratios range from 0. 83 to 1. 43. The distribution of fluorenes (F ),dibenzofurans (OF ) and dibenzothiophenes (SF)is summarized as follows:OF＞SF＞F,SF＞OF＞F or OF＞F＞SF. In the ΣSF/(ΣF+ΣSF)-ΣOF/(ΣF+ΣOF)diagram,they mainly are projected near the oxidation-reduction environments which may be a weak oxidation-weak reduction environment,whereas some samples also fall into an oxidation lacustrine or in a coal environment. The OEP ratios of the source rocks ranging from 1. 01～1. 16,C29ααα20S/ ααα (20S+ 20R) ratios ranging from 0. 17 to 0. 45,C29αββ/(ααα+αββ)ratios ranging from 0. 27 to 0. 49,and the calculations of aromatic maturity parameters MPI1 and 4,6/1,4-DMDBT from the equivalent vitrinite reflectances show that the Carboniferous source rocks in the Zaduo Group are mature in organic matter.关键词
石炭系/烃源岩/生物标志物/芳烃/羌塘盆地Key words
Carboniferous/source rock/biomarker/aromatic hydrocarbon/Qiangtang Basin分类
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陈文彬,付修根,谭富文,曾胜强,冯兴雷,宋春彦,王东..羌塘盆地东部石炭系杂多群分子地球化学特征及地质意义[J].沉积与特提斯地质,2018,38(2):14-22,9.基金项目
国家油气专项"羌塘盆地金星湖-隆鄂尼地区油气资源战略调查"(DD20160159)资助 （DD20160159）
