EARLY CRETACEOUS TECTONIC EVOLUTION OF LINGSHAN ISLAND IN SHANDONG PROVINCE AND ITS GEOLOGIC SIGNIFICANCE

Many structures, such as faults, folds, dykes, joints, have been found at the Lingshan Island. According to these structures, there were at least three compressional periods and two extensional periods from the Late Laiyang to Late Qingshan stages. Tectonically the study area suffered a NWW-SEE compression in the Late Laiyang stage, a NW-SE extension from the Late Laiyang stage to Early Qingshan stage, a nearly E-W to NE-SW extrusion after the Early Qingshan stage, a later NW-SE extension and a NW-SE extrusion. It is obvious that the tectonic stress field of this area is more complicated than that in the Jiaolai Basin. The clarification of tectonic stress mechanism and the evolution of stress field orientation are significant to restore the pro-type basin and the continental dynamics.