通过巴楚—麦盖提地区(巴麦地区)钻井和地震资料的详细分析,结合前寒武纪区域构造、沉积演化,将前寒武系顶面不整合划分为角度不整合、非整合、超覆不整合和平行不整合,这4类不整合分别揭示了裂谷、基底隆起、隆起斜坡和沉积坳陷等。进一步分析了不整合在平面上的分布特征,表明具有从非整合、超覆不整合向整合逐级过渡的分布规律。认为基底古隆起北缘以吐木休克断裂一带为界,南缘可能以铁克里克地区为界,其中基底古隆起的主体位于麦盖提地区和巴楚地区南缘,基底隆起的构造斜坡位于现今塔里木西南坳陷区、巴楚地区北部。基底古隆起演化上可分为前寒武纪平缓古陆阶段、前寒武纪末隆升加强阶段和早—中寒武世沉降埋藏阶段。总体上古隆起在前寒武纪具有南缓北陡特征,早—中寒武世具有南陡北缓特征,分别控制了南华纪—震旦纪和早—中寒武世地层发育和分布。
An unconformity analysis method is provided to study the basement paleo-uplift of Bachu-Markit area,Tarim basin. On the basis of regional tectonic and sedimentary evolution of previous research,we divided the Precambrian top surface to angle unconformity,nonconformity,overlap unconformity and parallel unconformity through the recognition of well data and seismic data. The four types of unconformity reflect rift,basement paleo-uplift,slope and depression,respectively. Furthermore,the distribution of unconformity has a gradual transition pattern,which is arrangement from nonconformity,overlap unconformity to conformity. We consider that the north boundary of basement paleo-uplift is Tumuxiuke fault zone and that the south boundary is possibly Tiekelike zone. Therefore,it could be affirmed that the main part of paleo-uplift is located in Markit area and the southern Bachu area; that the slope of paleo-uplift is distributed in present southwestern Tarim depressionand the northern Bachu area. The tectonic evolution of basement paleo-uplift can be divided into 3 stages,which are gentle Precambrian archicontinent stage,final Precambrian uplifting stage and Early-Middle Cambrian subsidence stage. As a whole,the paleo-uplift is gentle at the south and steep at the north in Precambrian;while it is contrary in Early-Middle Cambrian,which controls the strata development and distribution of Nanhuaian-Sinian and Early-Middle Cambrian.