Paleo-fires and Atmospheric Oxygen Levels in the Latest Permian:Evidence from Maceral Compositions of Coals in Eastern Yunnan,Southern China  

作　　者：SHAO Longyi WANG Hao YU Xiaohui LU Jing ZHANG Mingquan 

机构地区：[1]State Key Laboratory of Coal Resources and Safe Mining,and School of Geosciences and Survey Engineering,China University of Mining and Technology [2]Institute of Disaster Prevention [3]Coal Geology and Prospecting Institute of Yunnan Province

出　　处：《Acta Geologica Sinica(English Edition)》2012年第4期949-962,共14页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(41030213);the Major National S&T Program of China(2011ZX05033-002 and 2011ZX05009-002);the Fundamental Research Funds for the Central Universities in China(2010YD09)

摘　　要：Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian- Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the 02 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the PermianTriassic boundary crisis.Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian- Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the 02 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the PermianTriassic boundary crisis.

关 键 词：coal maceral INERTINITE paleo-atmospheric oxygen level WILDFIRE Permian-Triassic boundary 

分 类 号：P534.46[天文地球—古生物学与地层学] TQ536[天文地球—地质学]