Syndepositional tectonism in the Kvamshesten district (Old Red Sandstone), western Norway

Abstract

Summary Continental Middle Devonian sediments of the Kvamshesten district have recently been interpreted as a thrusted block. However, although basal contacts in the E of the district are mylonitized, contacts in the W can be interpreted as depositional unconformities. Coarse alluvial-fan breccias (Markavatn Formation) in the district's northern margins interdigitate with fluviatile sandstones (Heilefjell Formation) towards the basin's centre. Syndepositional tectonism is demonstrated by the geometry of the coarse marginal deposits.