桂西北二叠纪灰岩墙(脉)的地震成因解释

Interpretation of the seismic origin of Permian limestone dikes in northwestern Guangxi

广西西北部的泥盆纪灰岩中发育大量产状直立的二叠纪茅口组的碳酸盐岩岩墙,其成因一直引起地质学家的兴趣。本文尝试用地震灾变事件解释这一奇特的地质现象,即:二叠纪强地震发生时,茅口组未成岩的软沉积物中产生的液化沉积物流借助上覆沉积物的压力,贯入下伏已成岩的坚硬的泥盆系灰岩的裂隙(断层、节理等)中,形成具直立层理的灰岩墙(脉)。上述过程反映一次强地震灾变事件作用在软沉积物与坚硬岩层中的不同响应。

Many vertical limestone dykes of the Permian Maokou Formation are developed in Devonian limestone in northwestern Guangxi.Their origin has long attracted the interest of geologists.In this paper an attempt is made to use the seismic catastrophic event to interpret this unique geological phenomenon.When a strong earthquake took place in the Permian,the liquefied deposit flow produced in unlithified soft deposits of the Maokou Formation penetrated into fissures,faults or cleavages in the underlying Devo-nian lithified hard limestones under the pressures of the overlying deposits,forming limestone dikes with vertical bedding.The aforesaid process reflects different responses of soft deposits and hard rocks to a strong seismic catastrophic event.