陆相断陷盆地的构造层序地层分析

Tectono-sequence stratigraphic analysis in continental faulted basins

陆相盆地层序地层构型是构造运动、古气候、古湖平面变化与沉积物补给等动力学要素对沉积基准面控制的综合效应。其中,构造运动对盆地层序界面形成与层序内部充填起至关重要的作用。因此,陆相盆地层序地层研究须以构造层序地层为主线,即通过构造对层序形成与演化的控制分析解释层序地层构型,预测其内部充填特征。经研究,断陷盆地构造运动对层序地层的控制主要表现在:(1)断裂活动通过控制基底升降运动直接制约着盆地沉积物堆积的可容纳空间的变化及至层序地层构型;(2)构造转换带或调节带控制盆地主体物源补给方向和沉积体系分布;(3)断裂活动及其塑造的古地貌控制着沉积体系与砂体分布特征。

The sequence stratigraphic configuration in continental basins responds to base-level change controlled by integrated dynamic process, such as tectonics, paleoclimate, lake-level, sediment supply and so on. In continental basin, tectonic movements are extremely important to both the formation of sequence boundaries and the filling characters of sequence. The control of tectonic on sequence stratigraphic configuration in faulted basin can be summarized mainly as follows： （1） basement subsidence directly controls the change of accommodation for sediments accumulation and therefore, the change of sequence stratigraphic configuration; （2） tectonic transfer zones control the position of the source areas and the sedimentary system development; （3） palaeogeomorphology modified by tectonics/faulting influences the distribution of sedimentary system and sand bodies. Therefore, the sequence stratigraphic study in continental basins should focus on tectono-sequence analysis.