东营凹陷盐-泥构造的样式和成因机制分析

Study on structural styles and genetic mechanism of salt-mud tectonics in Dongying Depression

以地震剖面的精细解释为基础,借鉴典型盐或泥构造的研究成果,文中确立了东营凹陷盐-泥构造样式:盐-泥枕构造、盐-泥滚—滑脱断层簇—滚动背斜构造、盐-泥核背斜—拱顶断层簇构造。区域伸展作用下的重力滑动作用是东营凹陷盐-泥构造的主导成因机制。重力滑动作用表现为触发盐-泥层的聚集—隆升和引起薄皮滑脱作用。由此文中将盐-泥构造演化历程划分为盐-泥枕发育期和滑脱断层—盐-泥滚—盐-泥核背斜发育期。最终建立了东营凹陷盐-泥构造的成因-演化模式。

Salt-mud tectonics is a kind of tectonics resulted from the distortion of salt-mud bed flow, which is significantly different from pure salt or mud tectonics. Based on the detailed interpretation of seismic profiles with a seismic net spacing of almost 2 km, we have distinguished and defined the following salt-mud tectonic styles in the Dongying Depression= salt-mud pillow, salt-mud roller-detachment fault-rollover anticline and salt-mud core anticline-keystone fault family. The triggering mechanism for the salt-mud tectonics was gravita- tional gliding accompanying regional extension. Salt-mud bed accumulation and upwelling and thin-skinned detachment led to gravitational gliding. Consequently, the evolution of salt-mud tectonics may be divided into two stages： （1） a salt-mud pillow developing stage （before SB6＇）; （2） a detachment fault, salt-mud roller and salt-mud-core anticline developing stage （after SB6＇）.