古地理学报2009，Vol.11Issue(6)：689-696,8.
四川盆地东部上三叠统须家河组层序地层及聚煤特征研究
Sequence stratigraphy and coal accumulation of the Upper Triassic Xujiahe Formation in eastern Sichuan Basin
摘要
Abstract
The Xujiahe Formation of the Upper Triassic in the eastern Sichuan Basin is subdivided into seven members. The first member is correlated to the Xiaotangzi Formation of the western Sichuan Basin, but they have different facies. The first, third, fifth and seventh members are coal-bearing intervals, while the second, fourth and sixth members are sandstone-rich intervals. Four sequence boundaries represented by regional tectonic unconformities and the erosional base of the fluvial channel incised valley filling are recognized in the Xujiahe Formation based on outcrop and borehole data analysis. A total of four third-order sequences are subdivided in the Xujiahe Formation, and they are subcorrelated to the intervals of Member 1, Member 2 to Member 3, Member 4 to Member 5, and Member 6 to Member 7, respectively. Each sequence is further subdivided into lowstand systems tract(LST), lacustrine transgressive systems tract(TST) and highstand systems tract(HST)according to variation in lithology and lithofacies. The LST is characterized by widely distributed channel sandstones, the TST and HST are featured with the lacustrine-deltaic interbedded fine sandstones, siltstones, mudstones and coals. The further analysis of coal accumulation in the sequence stratigraphic framework reveals that, sequence 3 is the most favorable sequence for coal accumulation,followed by sequence 4,sequence 2 is the worst. Within sequence 3, the coal-accumulation in HST is better than in the TST. Thickness of coal seams is controlled by the balance between the peat accumulation rate and the accumulation creation rate,and the thick coals tend to be formed in the early HST when the peat accumulation rate is well balanced with the accumulation creation rate.关键词
四川盆地东部/层序地层/聚煤作用/须家河组Key words
eastern Sichuan Basin/sequence stratigraphy/coal accumulation/Xujiahe Formation分类
天文与地球科学引用本文复制引用
高彩霞,邵龙义,李长林,徐晓燕,许海涛..四川盆地东部上三叠统须家河组层序地层及聚煤特征研究[J].古地理学报,2009,11(6):689-696,8.基金项目
国家973项目(编号:2006CB202202)、国家油气重大专项(编号:2009ZX0509009-002)及国家自然科学基金项目(编号:40172050,40672103)联合资助 （编号:2006CB202202）
