Abstract
We made structural analysis for the gravitational tilting structures of steeply dipping cleavages in the Upper Permian alternating beds of siliceous slate and tuffaceous slate, and revealed their geological factors and formative process. The gravitational tilting has occurred due to two distinctive movements; creep as shearing along cleavage planes and topple as rotation of completely separated blocks. During the gravitational tilting deformation, creep has preceded, and continuously creep and topple have occurred simultaneously. Cleavage fractures have been selectively formed in tuffaceous slate, while rarely in red siliceous slate. Abundant quartz veins exist in red siliceous slate perpendicular or oblique to cleavages. These quartz veins prevent shearing along cleavage planes in red siliceous slate as anchor, and prompt formations of cleavage fractures in tuffaceous slate.
