摘要
中国大陆科学钻探松科1井南孔青山口组二、三段岩心中发育有4段深水震积岩,赋存在青二段底部到青三段底部的深湖砂岩薄夹层中。标志性震积构造有阶梯状断层、震裂缝、角砾状构造、重荷构造、砂球-砂枕构造(假结核)、液化扭曲变形构造、肠状构造、液化砂岩脉、假泥裂,均属同生-准同生期的软沉积变形构造,缺少震浊积岩表明是原地震积岩。青山口组震积岩展示了震积岩的一个发育模式和沉积序列,该序列由地震作用强烈时期发育的液化变形下部单元和地震作用衰减时期发育的塑性变形上部单元构成。松科1井南孔青山口组中火山物质与火山灰夹层共生。在金6井、金65井相当层位有橄榄粗安岩、火山角砾岩发育,乾124井、乾109井有玄武岩发育,这些井均位于孙吴-双辽超壳断裂一线,表明在青山口期有构造-火山事件的发生,震积岩是构造-火山事件引发的地震在深水环境中的记录。松辽盆地青山口期有构造-火山事件的发生,显示坳陷阶段也存在相当规模的断裂活动和火山喷发。
Drilling core from Chinese Continental Scientific Drilling-SK-I(s) presents four sets of deep lake seismite from the lower part of the second member to the bottom of the third member of Qingshankou Formation.Typical structures of the seismites include step micro-fault,seismic fissure bed,autoclastic brecciated structure,load structure,ball-and-pillow structure(pseudonodule),vibration-induced liquefaction structure,enterolithic structure,liquefaction sand dyke and pseudo-mud crack.All of these synsedimentary-penecontemporaneous soft-sediment deformation and absence of seismo-turbidite indicate that the seismites in Qingshankou Formation are previous soft sediment reconstruction related to earthquake.Seismites of Qingshankou Formation exhibit typical developmental pattern and sedimentary sequence of seismite.This seismic sequence consists of the lower unit of liquefaction deformation corresponding to strong earthquake and the upper unit of plastic deformation corresponding to earthquake attenuation.Mudstone with few altered glass shards and volcanic ash interlayers simultaneously developed in Qingshankou Formation from SK-I(s).Mugearite and volcanic breccia developed in well Jin6 and Jin65 and basalt developed in well Qian124 and Qian 109 during corresponding geological time of volcanic ash in SK-I(s).These four wells containing volcanic rock in Qingshankou Formation distribute along the Sunwu-Shuangliao transcrustal fault,which indicates that tectonic-volcanic activities occurred during Qingshankou period in Songliao Basin and seismites recorded earthquake activities induced by tectonic-volcanic event in deep water.Existence of tectonic-volcanic event in Qingshankou Formation suggests that fault activities and volcano eruptions should be normal phenomena during the sag stage in Songliao Basin.