High resolution sequence stratigraphy of the Late Permian coal measures in southwestern China

The Late Permian coal measures in southwestern China consist of a series of coal seams and sedimentary rocks formed in environments ranging from non-marine, paralic, to fully marine. In this paper, depositional environments of these coal measures have been discussed and a further analysis is made on high resolution sequence stratigraphy of typical paralic coal measures in western Guizhou. In each of the 17 fourth-order sequences, coal seams at base represent a transgressive systems tract and overlying limestone and siliciclastic successions represent a highstand systems tract, and the base of the limestone bed overlying coal seams represents a fourth-order maximum flooding surface. These fourth-order sequences have stacked into three third-order composite sequences in which lowstand, transgressive and highstand sequence sets can be distinguished based on stacking patterns of fourth-order sequences. These sequence sets can also be recognized through tracing landward distribution of coal seams and limestone beds which are believed to represent third-order marine flooding zones.