江苏西南部晚侏罗世西横山组沉积特征及成因

Sedimentary Characters and Their Genesis of West Hengshan Formation in Late Jurassic Epoch in Southwest Jiangsu

江苏西南部晚侏罗世西横山组为一套粗碎屑岩—细碎屑岩及泥灰岩组成的陆相沉积岩 ,普遍含有火山物质。从地层分布、岩性特征、碎屑岩粒度统计分析表明 ,天生桥盆地和西横山盆地基本上是连续、贯通的 ,自东向西 ,由冲积扇相—河流相—湖泊相逐渐过渡 ,属于同一水中盆地中不同沉积相的产物。沉积物主要来自盆地东部 ,可能与“古茅山”隆起带有关。

The west Hengshan formation in late Jurassic epoch of southwest Jiangsu is a set of continental sedimentary rocks composed of coarse to fine clastic rocks and marl,unconformably overlying Xiangshan group in middle and lower Jurassic series and containing volcanic matters.In the lights of stratigraphic distribution,lithologic features and grain size statistic analysis,Tieshengqiao basin and west Hengshan basin are demonstrated to be continuous and run-through on the whole,transiting from alluvial fan facies to river facies and lake facies,belonging to the outcomes of uniform water basins but different sedimentary facies.The sediments are mainly from the east of the basins,probably related with the mole track of “the old Maoshan”.