蒙古塔木察格坳陷白垩系震积岩特征及其地质意义

Characteristics of Cretaceous Seismite in the Tamuchage Depression,Mongolia,and Its Significance

通过岩芯观察,结合构造背景研究,在蒙古塔木察格坳陷白垩纪地层中识别出震积岩。震积岩的主要标志有微同沉积断裂、同沉积塑性变形构造、液化脉、震积枕状及伴生构造等。通过对塔21-9井、塔19-43井等岩芯的系统观察,建立了蒙古塔木察格坳陷白垩系震积岩的垂向序列。震积岩的垂向序列自下而上依次为砂岩脉(砂火山)层段、水塑性褶皱变形层段、斧式构造层段、滑塌构造层段、阶梯状微断层和震裂缝层段、准原地沉积湖泊津浪丘状层理和内碎屑角砾岩层段、异地沉积震浊积岩层段,对应于地震由强变弱的一个变化过程。震积岩的发现具有重要的研究意义,有助于分析盆地边界断裂的强烈活动时期。

Based on observation of drilling cores and study of tectonic setting, seismite was recognized in the Cretaceous strata of the Tamuchage depression. Seismite is mainly characterized by various soft-sediment deformation structures such as synsedimentary faulting and microfractures, liquefaction vein, pillow structure, and accompanying structures, etc. Based on observation of drilling cores from Ta 21-9 and Ta 19-43 wells, a vertical succession of seismites was established, which is in ascending order, liquefied veins, hydroplastic deformation, axe-formed, slump, ladder-shaped microfracture, and shatter fissure, and so on, which correspond to a change process of earthquake with an intensity from strong to weak. The discovery of seismites is of great significance and will be conducive to understanding of intense action period of basin-controlling boundary fault.