关键词: 羌塘盆地, 孔孔茶卡地区, 石炭系擦蒙组, 地球化学特征, 沉积环境分析

Abstract:

This paper focused on the study of the sedimentary environment about the source rock of Carboniferous Cameng Formation(C₂c) in Qiangtang basin, which characteristics of petrology, sedimentary facies and geochemistry were analyzed. The results reveal the following aspects: the sedimentary environment of the source rock in Carboniferous Cameng Formation is the delta deposit; the hydrolysable and ferrum elements are high abundant, indicating an onshore to shallow sea environment with shallowwater depth; the values of paleoclimate indexes (C) are all greater than 0.8, showing a humid environment; the ratios of Sr/Ba are all less than 1 within range of 0.13 to 0.23, indicating a low-salinity and fresh terrestrial sedimentary environment; the relationship of V/Sc, V/(V+Ni), Th/U, Ni/Co, Fe²⁺/Fe³⁺ with V/Cr all manifest an oxygen-enriched water environment. The above conditions are all favorable to mass propagation of terrestrial organisms and aquatic organisms, and these organic matters are transported and deposit, providing the materials of the source rock in the study area.

Key words: Qiangtang basin, Kongkong Chaka area, Carboniferous Cameng Formation, geochemical characteristic, sedimentary environment