Mesozoic Structure and Its Tectonic Setting in the Western Shandong Block

Abstract

Based on some results of 1∶50000 regional mapping in the western Shandong block, this paper mainly describes the Mesozoic deformation, basin prototype and their relation in the western Shandong block. Vertically, the Mesozoic structural levels in this block are divided into the lower, middle and upper levels, which are unconformably overlain by the Mid—Upper Jurassic, the Upper Jurassic—Lower Cretaceous and the Upper Cretaceous, respectively. In plan view, the deformation style shows three types, i.e. the E—W-striking open to tight folds and the related reverse faults of the Indosinian, the NNE- or NS-striking box fold and propagating thrust fault system of the middle Yanshanian movement, and the NE-striking slip fault and high-angle reverse fault system of the late Yanshanian movement. However, the deformation styles and basin prototypes in different parts of the western Shandong block varied evidently. This variation is derived from that of structural framework of the basement and the multiple-stage structural superimposition. The comprehensive study shows that the structure in the western Shandong block was formed in the dynamic setting of the continental marginal arc of the west Pacific, and under combined processes of the continental subcrust delamination and the continental intracrust extrusion.