The buried channels of the Exe

Abstract

Seismic refraction surveys of the buried channels of the Exe near Exmouth indicate the presence of an early period of channelling into New Red Sandstone breccias to a base in excess of −52 m* followed by a period of gravel infilling of these channels and then their partial re-excavation to a base in excess of −30 m. Terraces formed during stillstands within the early regression occur at depths of −25, −31·4, and −36 m and within the later regression at −5·8, −10.4, −13.7, −17·1, −22 and −27·1 m. Control of the orientation of the channels by fault planes within the New Red Sandstone is also indicated. Correlation of the periods of channelling with early and late Weichselian sea-level lows is suggested, indicating a middle Weichselian (Paudorfian) age for the gravels. Similarities with buried channels occurring in Southern Ireland are noted and wider correlations attempted.