Alluvial channel bank-collapse phenomena in the Old Red Sandstone Hitra Group, Western Central Norway

Abstract

AbstractThe Old Red Sandstone (ORS) on the island of Hitra forms an approximately 1350 m thick succession of alternating continental mudstones, sandstones and conglomerates of possibly latest Silurian to Devonian age. Within the middle part of this succession, just above a major, scoured surface, a spectacular slump feature was observed. The phenomenon is interpreted as a unit of overbank/channel bank mudstones which, because of undercutting and liquidization, caved into a low sinuosity river channel. The Hitra sequence is the only one in the Norwegian ORS where such phenomena have as yet been identified.