云南楚雄盆地西缘晚三叠世地震软沉积变形及灾变事件分析

    The Late Triassic seismic soft sedimentary, deformation and its event significance in the west margin of Chuxiong Basin

    • 摘要: 震积岩是古地震事件的重要记录,笔者在滇西楚雄盆地西缘斜坡浊流相罗家大山组中识别出震积岩体系。通过对罗家大山组剖面宏观露头和岩石薄片微观构造观察,总结了楚雄盆地西缘晚三叠世震积岩的识别标志,分为原地相脆性震积构造和软沉积变形震积构造,包括固结层脆性变形和疏松层软沉积变形,以及微断层、褶皱组合形成脆韧性构造、撕裂构造、自碎角砾岩、混滑层、液化卷曲变形、枕状构造、碟状构造、液化(角)砾岩、液化脉、沙火山、火焰状构造、负载构造、串珠状构造等。根据罗家大山组的震积岩特征,建立了斜坡相地震-海啸沉积序列。对这些震积岩的研究有利于对楚雄盆地西侧断陷盆地形成大地构造背景、活动时限的约束,并且可以指导在楚雄盆地内开展油气勘查。

       

      Abstract: Seismites are the important recorder of ancient earthquake. Seismites were recognized from foreslope turbidity facies Luojiadasha Formation rocks, in west margin of Chuxiong Basin. Based on the observation of field outcrop and thin section of the Luojiashan Formation, the identification marks of the Late Triassic seismites in the western margin of the Chuxiong Basin were summarized. The seismicity structure of the in-situ phase is divided into brittle seismotectonic type and soft deformable seismotectonic type, including stepmicro-faults, seismo-folds, brittle, brittle ductile structure, tearing structure, self-fragmental breccia, mixed slip layer, liquefied curl deformation, pillow structure, disc structure, liquefied, liquefied veins, sand volcano, flame-shaped structure, load structure and bead structure flow seismites rocks. Based on the study of stratigraphic column, seismite sequence has been created. It is of important significance for the study of tectonic evolution and the times of faulting basin and guarding the exploration of oil-gas in the Chuxiong Basin.

       

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