北山—阿拉善地区侏罗纪盆地构造特征及其演化

The Structural Characteristics of Jurassic Basins and Their Evolution in Beishan--Alaxa Area

北山—阿拉善地区侏罗纪盆地受近东西向断层的控制 ,为东西向展布的断陷湖盆 ;盆地经历了早、中侏罗世断陷、晚侏罗世坳陷及其以后的改造三大阶段。目前控制侏罗系展布的断层有正断层、逆冲断层和反转断层等。白垩纪盆地受北东向断层的控制 ,对侏罗纪盆地进行了叠合改造。两个时代的盆地在空间上存在翘倾叠合、叠合保存、部分叠合改造三种干涉方式。盆地的叠合保存区对侏罗系烃源岩埋藏较好 ,对油气形成有利。

Jurassic basins are controlled by near EW--trending faults in Beishan--Alaxa area, and the faulted basins extend in EW direction. The basins experienced extending faulted depression in Early and Middle Jurassic, depressing in Late Jurassic and reformation. The Jurassic strata are controlled by normal faults, reverse faults and inverted faults. Cretaceous basin superposed on Jurassic basin is controlled by NE--trending faults. There are three superposed manners between Jurassic and Cretaceous basins existed in space. Jurassic source rocks are preserved well in superposed area and is favorable for oil and gas formation.