浅析龙门山前陆盆地须家河组二段软沉积物变形

Analysis of soft sediment deformation of the second member of Xujiahe Formation in Longmenshan foreland basin

龙门山前陆盆地是中国典型的前陆盆地,在晚三叠世早期该盆地位于扬子板块西缘。在龙门山晚三叠时期的造山运动中,导致了龙门山地区的抬升。乐地1井位于龙门山前陆盆地南侧,通过对乐地1井岩芯的观察,结合前人对四川盆地晚三叠统须家河组地层的研究,在须家河组二段地层中识别出大量沉积物变形,包括液化砂岩脉、包卷层理、火焰状构造、震裂结构、丘状交错层理等。通过对比现今事件沉积物,结合前人研究成果,将须家河组二段中形成的软沉积物变形划分为四个沉积事件,将其中第二次事件沉积为地震海啸成因。

The Longmenshan foreland basin is a typical foreland basin in China.In the early Late Triassic,the basin was located in the western margin of the Yangtze plate.The Late Triassic orogeny in the Longmen Mountain resulted in the uplift of the Longmen Mountain area.To 1 well is located in the longmen mountain,the south foreland basin,through the observation of the music to 1 well core,combining previous to the sichuan river basin in the late Triassic xujiahe formation in the study,the river in the xujiahe group 2 large amount of sediment is identified in the deformation,including liquefied sandstone veins,lapped bedding,flame structure,shatter structures,hummocky cross-bedding,etc.By comparing the present event sediments and combining the previous research results,the soft sediment deformation formed in the second member of Xujiahe Formation was divided into four sedimentary events,among which the second event was deposited as the cause of earthquake and tsunami.