鄂尔多斯盆地三叠系延长组震积岩特征研究

Discovery and Significance of Seismites in Late Tertiary Yanchang Formation of 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。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。

Seismites is a kind of catastrophic event rock. By the observation of drilling cores, there are many special structures which were generated by ancient widespread earthquake recorded in the seismites of the Triassic Yangchang Formation in Ordos Basin, such as liquefaction sandstone vein, fault-graded, vibrational liquefaction deformation structure, pillow structure, ball structure, tearing mudstone fragment and slumps. The vertical sequence of seismites in Triassic Yangchang Formation, from bottom to top, included 7 units： underlying unshocked layer, shattered layer, ladder-shaped faulted layer, vibrational liquefaction deformation structure bed, liquefied sandstone vein bed, pillow structure and partner structure layer,homogenized bed and overlying unshocked layer. The first discovery of seismites could be used to analyze the intensively active period of basin-controlling boundary, and the seismites themselves were a kind of potential reservoir.