关键词: 二叠纪, 龙潭组砂岩组分, 物源分析, 安徽东南部

Abstract:

          Detrital composition analysis of  sandstone  is mainly used  to  study  the provenance of  sediments and  the  tectonic
background evolution. The Longtan Formation  is one of  the major coal-bearing strata  in South China. The characteristics of
sandstone detrital compositions of  the Permian Longtan Formation  in southeastern Anhui province show  that  the contents of
monocrystal quart is mostly 25%-40%, and the polycrystal quart 30%-65%. The quart in the fine-grained sandstone usually has
a corroded rim. The contents of feldspar show a great variation, mainly 5%-15% in the fine-grained sandstone and about 1% in
the medium- to coarse-grained sandstone; Lithic fragments are mainly 15%-25% in the fine-grained sandstone and 10%-20% in
the medium- to coarse-grained sandstone. The sandstone detrital compositions and provenance analysis indicate that the sandstone of  the Longtan Formation was derived  from  the mixed sources of  recycled orogen and subduction complex. Combining with  the  gravel characteristics and  the regional  tectonic setting,  it can be  inferred  that  the sources of  the Longtan Formation  in  the study area were mostly derived from the collision zone between the Cathaysia Plate and the Yangtze plate, namely the Jiangnan orogen

Key words: Permian, Longtan Formation, components of sandstones, provenance, southeastern Anhui Province