羌塘盆地戈木错地区泥火山群沉积及浅表地球化学特征

Sedimentary and geochemical characteristics of the mud volcanoes in the Gemucuo Lake area,Qiangtang Basin,northern Xizang

本文对羌塘盆地戈木错地区的泥火山群进行了沉积学及地球化学的研究。研究区泥火山沉积物主要为第四系风化沉积物及被流体带到地表的下伏地层岩块组成。酸解烃法、蚀变碳酸盐法(△C)对土壤样品的研究结果表明,样品含有的有机酸解烃成分具有完整C1-C5序列;烃类各组分间、烃类和碳酸盐指标间具有显著的正相关性;烃类气体来源为原油伴生气和凝析油气,显示出深部热解成因气的特征。

Sedimentary and geochemical approaches are made for the mud volcanoes in the Gemucuo Lake area, Qiangtang Basin, northern Xizang. The mud volcanic deposits herein consist mostly of the Quaternary weathering sediments and the rock fragments from the underlying strata. The analytical results of the soil samples obtained by using the acidolytical hydrocarbons method and altered carbonate method （△C） show a complete sequence from C1 to C5 , i. e. , C1 〉C2 〉C3 〉C4 〉C5 . There is a significant positive correlation in geochemical signatures for the acidolysis hydrocarbons and altered carbonates. The hydrocarbon gas types in the near-surface area of the Gemucuo Lake area are represented by the crude oil-associated gas and condensate oil-associated gas, characteristic of depyrolysis.