山东省莱西地区白垩纪王氏群地层中的滑塌构造及其成因

Slump Structures and the Origin of Cretaceous Wangshi Group in Laixi Area in Shandong Province

摘要:

滑塌构造不仅具有沉积学意义，同时能为区域大地构造背景研究提供沉积学证据。在莱西地区进行野外地质调查中，首次在白垩纪王氏群林家庄组底部地层中识别出滑塌构造。在对该滑塌构造进行观察、描述和分析的基础上，将整个滑塌构造自上而下划分为弱变形层、阶梯式断裂发育层、软沉积变形层、未变形层。滑塌体主要由各种类型的滑塌褶皱、滑塌面、同沉积断层、砂岩球枕体、负载构造等组成。结合区域构造背景分析认为，其成因可能是在火山活动引发的地震触发下，半固结的沉积物在斜坡地带沿膨润土化流纹质凝灰岩构造薄弱界面发生滑塌，向盆地中心方向滑动形成。

Abstract:

Slump structures not only have sedimentological significance, but also provide sedimentary evidence for the restoration of regional geotectonic setting. In the field investigation in Laixi area, the slump structures have been identified for the first time in the bottom strata of Cretaceous Linjiazhuang formation of Wangshi group. Based on the observation, description and analysis, the slump structures can be divided into weakly deformed layer, stepped fault layer, soft-sediment deformation layer, and undeformed layer according to the deformation strength and the way of deformation of the profile. The whole slump body is mainly composed of various types of slump folds, slump surface, syn-sedimentary faults, sandstone ballandpillow, and load structures. According to the analysis of regional tectonic background, the origin of the slump structures may be due to the earthquake caused by volcanic activity. The semi-consolidated sediments slide along the weak interface and toward the center of the basin.