塔里木西南地区二叠纪沉积环境演化

Permian Sedimentary Environment Evolution in Southwest Tarim

塔里木西南地区二叠系分布广泛,认识其沉积和演化特征对分析二叠系油气资源潜力意义重大。结合前人研究成果,通过山前露头剖面观测、盆地钻测井解释、岩心观察、样品分析测试等,认为二叠系主要发育开阔台地、局限台地、潮坪、浅海混积陆棚、三角洲、冲积扇、滨浅湖相等多种沉积相类型。分析塔里木西南地区二叠系下、中、上统发育的主要沉积相类型,认为从早二叠世至晚二叠世,其为一个从海洋到陆地的演化过程,演化受控于海平面变化、构造活动、沉积物源供给和气候变化。不同时期,主控因素不同。下二叠统的形成受控于海平面处于相对高水位;中二叠统的形成受控于海平面下降和火山活动,海平面下降导致气候逐渐炎热干燥;上二叠统的形成受控于构造活动,构造活动导致地形变化和沉积物源的供给。

Permian in Southwest Tarim widely distributed,analyze its sedimentary characteristics and evolution as a whole regionally is significant for prediction of oil-gas resource potential.Through of foreland outcrop observation, drilling and well logging interpretation, core observation and sample analysis, combined with previous known results, 7 main developmental facies （open platform facies, restrcted platform facies, tidal-flat facies, shallow clasolite-carbonatite continental shelf , delta facies, alluvial fan facies, shore-shallow lake facies） are recognized in Permian. The main development types of sedimentary facies of the lower, middle and upper Permian in southwestern Tarim are analyzed, from the early Permian to late Permian, it is a process of evolution from marine sediments to the continental sediments, which is controlled by the sea level change, tectonics, sediment supply and climate change, in different periods, the main controlling factor is different. The formation and development of the Lower Permian is mainly controlled by sea level in a relatively high water level;The formation of Middle Permian is controlled by falling sea level and volcanic activity, sea level fall causing the climate gradually become dry and hot;the Upper Permian formation is mainly controlled by tectonic activity, which resulted the morphological changes and sediment source supply.