Sedimentological Charateristics And Palaeoenvironmental Bearings Of The Late Permian Coals In Eastern Yunnan And Western Guizhou Of Southwestern China

The sedimentological characteristics and palaeo-environmental bearings of the Upper Permian coal measures in sw China are studied employing sedimentology, coal petrology, signal analysis and isotopic geochemistry of carbon and sulfur. High resolution sequence stratigraphic analyses delineate the Upper Permian into three 3rd-order composite sequences and sixteen 4th-order sequences. Inertinite, which is largely the by-product of palaeo-fire, accounts for a significant portion of the coal macerals, suggesting the temporal atmosphere was enriched in O2 and the peatland was suffered from frequent wildfires. Spectral analysis of geophysical loggings, which reflects the ash varations in the coal, reveals that the coal deposition was influenced by Milankovitch cycles. Calculations of NPP and carbon accumulation rate of coal-forming peatland support that the productivity in the peatland was strongly influenced by the high content of the temporal O2. A13Corg and?34Sorg of Late Permian coals show shifts which are correlative with the phenomenon in global marine and terrestrial sections, suggesting inherent links between mechanisms which perturbed the temporal C and S cycles, and the crisis on land was later than the sea. All these knowledges confirm the feasibility of using coal as a media for palacoenvironmental study, and are of great importance to improve our understanding towards the behavior of terrestrial system in the Late Permian event.