陆相碎屑震积岩形成机理及其研究意义

Formation Mechanism and Significance of Continental Clastic Seismites

震积岩是国内近几年研究的热点之一,越来越多的震积构造在古代地层中被识别出来。通过对不同盆地陆相碎屑岩典型震积构造的研究,对不同震积岩的形成机理进行了深入分析。研究认为陆相碎屑震积岩大多与砂土的液化作用有关,同生小断层应形成于砂土液化和微褶皱发生之后的应力调整期,其垂直断距应与下伏不同粒度砂岩的差异沉陷量相当。陆相碎屑震积岩主要受控于沉积相带或者岩性,因而并不具有统一的垂向沉积序列,但在粉砂质和泥级沉积物中可以发育与碳酸盐岩震动液化地震序列相似的沉积构造组合。震积岩的研究对构造—沉积演化史分析、地震预测、油气勘探和开发以及区域地层对比都具有重要意义。

The seismites is one of the research hotspots in recent years. With the deepening of the study, more and more seismite structures have been identified in ancient strata. Based on the study of typical seis mites in different base, the paper analyzes formation mechanism of different seismite. Many continental clastic seismites＂ structures related to sand liquefaction. Micro normal fractures were formed t during stress adjustment which was occured after liquefaction of sands and micro corrugating. Vertical fault throw of mi- cro normal fractures is equal to the differential subsidence of sands that have different particle size. Conti- nental clastic seismites have no general sediment sequence because its distribution was mainly controlled by sedimentary facies or lithology. But similar sequence to vibration liquefaction in carbonate rock can be found in silt and clay size deposit. Seismites research is significant to structural-sedimentary evolvement a- nalysis,earthquake forecast, exploration and development of oil ~ gas and regional stratigraphic correlation.