济阳坳陷古近系碎屑岩地层中震积岩识别标志研究

在陆相湖盆中，地震引起的各种作用力可以对各种先成沉积物进行改造而形成震积岩，建立准确可信的识别标志是震积岩研究中最关键的问题之一。应用大量岩心、薄片和成像测井分析资料，对济阳坳陷古近纪沙河街组砂泥质沉积中地震灾变事件的：典型识别标志及其成因进行了研究。结果表明，震积作用可以形成特殊的构造标志（层内阶梯状微断层、震裂缝、混合层构造等）、沉积和成岩标志（液化砂、泥岩岩脉和泄水构造、串珠状构造、震积砂枕及砂球构造、液化卷曲变形构造等）及特殊的岩石类型（震褶岩、震裂岩、震塌岩及液化角砾岩等）。研究区未固结富含孔隙水的软沉积物以地震液化序列为主，半固结或固结的沉积物以断裂和破碎变形的震积序列为主，序列的完整性取决于剖面位置、地震震级及地震持续时间，特别是发生地震处的岩性。此研究可识别陆相湖盆地震事件沉积，提供判断储集砂体成因的对比标准，为正确判断储集砂体的“多元”性提供地质理论依据。

Study on the distinguishing marks of seismites in clastic rock strata of Paleogene in Jiyang depression

The seismites are developed through the formed sediments reformed by seismic forces in lacustrine basin.Establishing the accurate and reliable distinguishing marks is one of the most critical problems of researching seismites.Based on core observation,thin section and imaging logging analysis,the typical distinguishing marks and genesis of seismic disaster event in arenaceous-pelitic sediments,Shahejie formation of Paleogene in Jiyang depression were discussed.During earthquake,some deformation structures(step microfault,microfissure and mixed layers),sedimentary and diagenitic structures(liquefied sandstone vein,liquefied mudstone vein,water-escape structure,pillow structure,ball structure,pinch-and-swell structure and convolute lamination) and special rocks(seismic corrugated rock,shattering rock,seismic fall-masses and liquefied breccia) are formed.The seismic liquefied sequence of unconsolidated soft sediments with high content of pore water and seismic sequence of semi-consolidated or consolidated sediments dominated by fracture and broken deformation were summarized.The feature and integrity of sequences depend on the location of section,magnitude of earthquake and duration time,especially lithologic characters of seismic area.The research about distinguishing marks of lacustrine seismite cores and genesis provide geologists with one of correlation standards for identifying the event deposition of lacustrine basin and judging the genesis of reservoir sandbody as well as theoretical foundations for judging the 'polygenesis' of reservoir sandbody in Jiyang depression.