羌塘盆地昂达尔错地区侏罗系烃源岩生物标志物特征及其指示意义

以烃源岩抽提物的饱和烃色谱-质谱分析为基础，剖析了羌塘盆地昂达尔错地区3套主要烃源岩的生物标志物特征，探讨了其沉积环境和成熟度指示意义。研究表明：下侏罗统曲色组烃源岩具有较高的（C₂₁+C₂₂）/（C₂₈+C₂₉）、Ts/Tm、C₃₁藿烷S/R及重排甾烷/规则甾烷比，以腐泥型、腐殖腐泥型海相有机质输入为主，呈成熟烃源岩特征；中侏罗统布曲组烃源岩以相对较低的Pr/Ph和C₁₉/C₂₃三环萜烷比区别于其他2套烃源岩，沉积于较强的海相还原环境，呈腐殖腐泥型、腐泥型有机质输入和低熟-成熟烃源岩特征；中侏罗统夏里组烃源岩沉积于低盐度海陆过渡环境，有机质类型以腐殖型和腐泥腐殖型为主，显示低成熟烃源岩特征。

Biomarker characteristics of Jurassic source rocks in Angdarco area in Qiangtang Basin and their significance

The characteristics of biomarkers for three sets of main source rocks in Angdarco area of the Qiangtang Basin were studied, and the significance for sedimentary environment and thermal maturity was discussed, based on the analyses of saturated hydrocarbon chromatogram and mass spectrometry. Thermally mature source rocks from the Lower Jurassic Quse Formation have relatively higher ratios of (C₂₁+C₂₂)/(C₂₈+C₂₉), Ts/Tm, C₃₁ homohopane S/R, and rearranged sterane/regular sterane. The main sources were sapropelic and humic-sapropelic marine organic matter. Source rocks from the Middle Jurassic Buqu Formation were deposited in a reducing environment, and were distinguished from the other two source rocks by relatively lower ratios of Pr/Ph and C₁₉/C₂₃ tricyclic terpane, which indicated sapropelic and humic-sapropelic organic matter inputs, at low mature to mature stage. Source rocks from the Middle Jurassic Xiali Formation were deposited in a marine-terrestrial transitional environment with a lower salinity, presenting humic and sapropelic-humic organic matter inputs, and low thermal maturity.