Sedimentary environments and coal accumulation patterns of the Lower Cretaceous Shahai Formation in Fuxin Basin，Liaoning Province
Cai Hou′an1,2, Li Baofang2, Shao Longyi1, Xu Debin2, Shao, Kai1, Zhou Yuanyuan1
1 State Key Laboratory of Coal Resources and Safe Mining，China University of Mining and Technology (Beijing)，Beijing100083 2 School of Energy， China University of Geosciences(Beijing)，Beijing100083
Abstract：The research on sedimentary environment and coal accumulation pattern of the Lower Cretaceous Shahai Formation in Fuxin Basin is relatively insufficient.Based on field observation and combines the observation and description of borehole cores and outcrop sections，across well profile analysis and well logging curves, the authors analyzed the sedimentary environments and coal accumulation pattern of the Shahai Formation in Fuxin Basin.The result shows that alluvial fan-fan delta sedimentary systems and lacustrine sedimentary system were developed in the Shahai Formation of the Fuxin Basin.The Shahai Formation can be divided into 3 third-order sequences and each sequence can be further subdivided into transgressive systems tract and highstand systems tract.Among them，the Members 1 and 2 of the Shahai Formation belong to Sq1，the Member 3 of Shahai Formation belongs to Sq2 and the Member 4 of the Shahai Formation belongs to Sq3.Coal seams of the Shahai Formation are mainly distributed in Sq2.Coal accumulation centers of transgressive systems tract of Sq2 are distributed in the Qinghemen-Yimatu County，South Dongliang County and Jiudaoling County，while those of highstand systems tract in Sq2 are located in the Qinghemen County and Jiudaoling County.Depositional models of coal formation in the Shahai Formation include inter-fan paludification coal formation in the transgressive systems tract and deltafront coal formation in highstand systems tract，among which the former is better than the latter.
