鄂尔多斯盆地三叠系延长组震积岩特征及其地质意义

Seismite Characteristics and its Geological Significance of Triassic Yanchang Formation in Ordos Basin

震积岩是具有古地震记录的岩层。根据大量岩心观察，鄂尔多斯盆地三叠系延长组广泛发育震积岩沉积标志，如液化砂岩脉、阶梯状小断层、液化卷曲变形、砂球枕构造、泥岩撕裂屑、滑揉构造等。本文详细分析了各种震积岩特征及其分布，初步建立了鄂尔多斯盆地延长组震积岩垂向沉积序列，包括：A段为下伏未震层；B段为微同沉积断裂层；C段为振动液化卷曲变形层；D段为液化砂岩脉和砂岩墙段；E段为砂球枕及碎块层；F段为液化均一层和G段上覆未震层。震积岩的首次发现为研究盆地周边构造演化强度和期次提供了佐证。同时震积岩也是一种潜在的有利储层．

According to large core observation, seismite deposition signs are widely developed in the Triassic Yan-chang Formation, Ordos Basin, such as liquefied sandstone dykes, small ladder-like faults, liquefied curly deformation, sand baH-pillow structures, tearing shale debris, sliding-kneading structure, etc. In this paper, a detailed analysis of various seismite characteristics and distribution is presented, and a vertical sedimentary sequence of the seis- mite in the Yanehang Formation of the Ordos Basin is initially established, including： section A, the unshocked un- derlying layers; section B is the slight-synsedimentary fractured formation; section C is the vibratedly liquefied curly deformation layers; section D is the liquefied sandstone dykes and sand dikes; section E is the sand ball-pillow and fragments layers; section F is liquefied uniform layers and section G the overlying unshocked layers. The first time discovery of seismite provides an evidence for studies of the strength and period of time of the basin＇s surrounding tectonic evolution. At the same time the seismite is a potentially favorable reservoir.