楚雄盆地西缘下侏罗统冯家河组震积岩特征及其地质意义

    Characteristics and geological significance of seismites in the Lower Jurassic Fengjiahe Formation in western Chuxiong Basin

    • 摘要: 震积岩是古地震事件的重要记录,依托大比例尺区域地质调查,在滇西楚雄盆地西侧陆相红层冯家河组中识别出一套陆相震积岩体系。通过对宏观露头和岩石薄片微观观察,总结了该套地层的震积岩标志,主要包括微断裂、震褶岩、液化变形构造、砂岩脉、沙火山、负荷构造、火焰构造、枕状构造、球状构造、角砾岩化、地裂缝等原地相的震积构造及震浊积岩、震积泥石流等异地相震积岩。综合地层柱状结构图,建立了冯家河组陆相震积岩垂向震积岩结构序列。冯家河组震积岩的发现对研究楚雄盆地构造演化具有重要意义,并为楚雄盆地油气勘探提供了地质依据。

       

      Abstract: Seismites constitute the important recorder of ancient earthquake. By the observation of sheet geological survey and the studies of thin section, the seismites were recognized in Fengjiahe Formation, West Chuxiong Basin. The syn-sedimentary deformation serves as the main marker, the seismic structure of the in-situ phase includes such factors as stepmicro-faults, seismo-folds, fluidized soft structures, fluidized veins, sandy volcano, load casts, flame structures, pillow structures, ball structures, brecciation, seismo-cracks, whereas the dissimilarly seismites include seismoturbidite and debris flow rocks. Shock fold rock, vibrational liquefaction clay veins, flame structure, convolution beddings and pinch and swell structures. Through the study of stratigraphic column, seismite sequence was put forward. The establishment of Fengjiahe Formation seismites has important significance for the study of tectonic evolution in Chuxiong Basin, and can provide important foundation for the exploration of oil-gas in Chuxiong Basin.

       

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