| The Upper Permian Longtan Formation is a complete 2nd-order parasequence that includes fifteen 3rd-order subsequences in the northeast Jiangxi province. The paleogeographic chacracteristics of Longtan sediments in vertical and lateral is described according to sedimentary system tract that is divided into 7 stages. Three phases of barriers formed during Longtan age, which are the upper Guanshan Member, Shizishan Member and the upper Yupanli Member. Environments of coal formation are commonly relative with tidal hydrodynamics and different sorts of coals that formed under different tidal flat environments are of quitely different hydrocarbon-generating conditions. The best quality of coal
that can generate hydrocarbon is the Leping bark coal, which only developed in the middle zone of degrading gentling tidal fat. |
