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

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.