内蒙古西部额济纳旗雅干地区二叠系哈尔苏海组沉积环境

摘要

The sedimentary environment of Permian Haersuhai Formation in Yagan area of Ejin Banner was analyzed and the evidence for evaluation of oil/gas geologic conditions of Carboniferous-Permian was provided. The sedimentary environment was studied on the basis of lithology, paleontology and sedimentary structure, in combination with the content and ratios of trace elements as well as geochemical parameters of saturated hydrocarbon by gas chromatography. The study shows that there was a large-scale regression in Yingen-Ejin Banner basin in late Middle Permian period. Marine deposits of the Upper Permian Haersuhai Formation are mainly developed in Ejin Banner -Yangan -Hangwula area. Sediments consist of pyroclastic rock and clastic rock intercalated with a small amount of carbonate rock. It is concluded that the Permian Haersuhai Formation in Yagan area was formed in an offshore -epeiric sea- continental/oceanic alternate environment characterized by brackish water.%根据地层与古生物、沉积构造、岩性特征、成岩作用,结合微量元素组分含量和某些元素的比值、饱和烃气相色谱地球化学参数,综合研究额济纳旗雅干地区二叠系哈尔苏海组的沉积环境,为研究区石炭系—二叠系油气地质条件评价提供依据.研究结果表明,银-额盆地中二叠世末期发生过大范围的海退,晚二叠世哈尔苏海组海相沉积主要发育于额济纳旗—雅干—杭乌拉一带,以火山碎屑岩-碎屑岩夹少量碳酸盐岩沉积为主.说明额济纳旗雅干地区二叠系哈尔苏海组形成于半咸水的浅海-滨海-海陆交替的环境.