Permo-Carboniferous coal measures in the Qinshui Basin: lithofacies palaeogeography and its controls on coal accumulation
Shao Longyi, Xiao Zhenghui, Luo Wenlin, He Zhiping, Liu Yongfu, Zhang Pengfei
Key Laboratory of Coal Resources of Chinese Ministry of Education and the Department of Resources and Earth Sciences, China University of Mining and Technology, Beijing, 100083
The Qinshui Basin in southeastern Shanxi Province is an important base for coalbed methane exploration and production in China. The methane reservoirs in this area are the Carboniferous and Permian coals and their thickness are strongly controlled by the depositional environments and palaeogeography. In this paper, sedimentological researches were conducted on the outcrop and borehole sections of the Taiyuan and Shanxi Formations in the Qinshui Basin and the basin-wide lithofacies palaeogeography maps for these two formations have been reconstructed. The Taiyuan Fomation is composed of limestones, aluminous mudstones, siltstones, silty mudstones, sandstones, and mineable coal seams, with a total thickness varying from 44.9 m to 193.48 m. The coal seams have a thickness ranging between 0 and 16.89 m, averaging 7.19 m. During deposition of the Taiyuan Formation, the northern part of the study area was dominated by the lower deltaic depositional system, the central and southern parts were dominated by the lagoon environment, the southeastern corner was occupied by the carbonate platform setting. Coal is relatively thick in the northern part and the southeastern corner. The Shanxi Formation consists of sandstones, siltstones, mudstones and coals, with the limestones being locally developed. The thickness of the Shanxi Formation is from 18.6 m to 213.25 m, with the thickness of coal seams being from 0 to 10 m and averaging 4.2 m. During deposition of the Shanxi Formation, the northern part of the Qinshui Basin was mainly dominated by lower deltaic plain distributary channel environment, the central and southern parts were mainly the inter-distributary bay environment, and the southeastern part was occupied by the delta front mouth bar environment. The thick coals are distributed in the central and southern parts where the inter-distributary bay was dominated. It is evident that the distribution of thick coal zones of the Taiyuan Formation is consistent with the distribution of sand-rich belts, mainly located in the areas of northern lower deltaic plain and southeastern barrier bar environments, while the distribution of the thick coal zones of the Shanxi Formation coincides with the distribution of mudstone-rich belts, located in the areas of the central and southern inter-distributary bay environment.
About author: Shao Longyi, born in 1964, graduated and obtained his Ph.D. degree from China University of Mining and Technology (Beijing) in 1989. Now he is a professor of geology in the Department of Resources and Earth Sciences of China University of Mining and Technology (Beijing), with main research interests in Sedimentology and Palaeogeography of fossil fuel deposits.
Cite this article:
. Permo-Carboniferous coal measures in the Qinshui Basin: lithofacies palaeogeography and its controls on coal accumulation[J]. JOURNAL OF PALAEOGEOGRAPHY, 2005, 7(4): 535-548.
. Permo-Carboniferous coal measures in the Qinshui Basin: lithofacies palaeogeography and its controls on coal accumulation[J]. JOPC, 2005, 7(4): 535-548.