The coal-bearing strata comprise clastic-carbonate mixed shore zone sediments, delta sediments and fluvial sediments, with fluvial sediments predominating.

• 该区的含煤地层虽包括碎屑-碳酸盐混合滨岸沉积、三角洲沉积及河流沉积三大类,但以河流沉积为主。