Sedimentary Facies and Coal Accumulation of the Northern Type Longtan Formation in Central Hunan,Southern China

摘要

The northern type Longtan Formation of the Late Permian in central Hunan is dominated by an assemblage of greyish black mudstone,siltstone, sandy mudstone,fine sandstone and coals,and contains a variety of sedimentary structures such as thin sandstone-mudstone interbedded bedding,flaser beddings,lenticular beddings,horizontal