The early Middle Jurassic was an major coal-forming period in the region, when the Lower Yaopo Formation of lacustrine-deltaic and swampfacies was deposited.
中侏罗世早期是全区重要的成煤期，下窑坡组为湖泊—三角洲及沼泽相。
2
In terms of molecular geochemistry indexes, the hydrocarbon source rocks both in lower Jurassic and middle Jurassic can be classified as lake facies and swampfacies.
根据分子地球化学指标，下侏罗统和中侏罗统烃源岩都可划分为湖相和沼泽相两类。
3
Sediments in basins consist of grey coal-bearing formation composed of fluvial alluvial, proluvial fac ies, lacustrine-swampfacies. The material composition of sedim…