湖南石门杨家坪上震旦统陡山沱组生物标志物组成

BIOMARKER CONSTITUTION OF UPPER SINIAN DOUSHANTUO FORMATION AT YANGJIAPING, SHIMEN, HUNAN

戴卿林 林壬子 罗柳忻 文志刚

Dai Qinglin Lin Renzi Luo Liuxin Wen Zhigang

据灰岩、含碳质灰岩、碳质页岩三个典型样品的分析,中扬子地区扬家坪剖面上震旦统陡山沱组富含生物标志物,反映了藻类和细菌的输入。灰岩和页岩生物标志物分布的差异表明,沉积环境是主要控制因素;灰岩构型异构化作用比页岩慢。

The distribution characteristics of biomarkers in Upper Sinian Doushantuo Forma-tion at YangJiaping,Middle Yangzi Region were studied through analysing three typical samples of limestone,carbonaceous limestone and carbonaceous shale.The biomarkers in Doushantuo Formation include n-alkanes,n-alkylcyclohexanes and methyl-n-alkylcyclohexanes.The content of regular sterane with C sterane predominance is much higher than that of rearranged sterane.The contents of tricyclic terpane and pentacyclic triterpane are higher.Gammacerane,carotanes,pristane and phytane are widespread.Biomarkers in Upper Sinian Doushantuo Formation suggest that the organic matter comes from algae and bacteria.The differences of biomarker distribution in lime-stone and shale in Doushantuo Formation indicate that sedimentary environment is the main factor in controlling biomarker distribution,and the stereoiso merization of limestoneis slower than that of shale,suggesting a higher thermal evolution degree of shale than that of limestone.Though the formation in the Middle Yangzi Region is rich in fine or-ganic matter,but it is only possible to have gas-source potential due to the overmature ofthe organic matter.

10.11743/ogg19930413