Late Oligocene terrestrial sediments from a small basin in the Little Minch

Synopsis Borehole 80/14 in the Little Minch recovered grey, carbonaceous clays with sandy horizons and abundant plant remains from a small basin adjacent to the Minch Fault. Pollen from the sediment is characterised by a verus-vestibulum association that demonstrates a Late Oligocene (Chattian) age and indicates a terrestrial floodplain environment with arborescent swamps and fens. Both the age and lithology of the deposit are therefore similar to other terrestrial Oligocene basins found in the western British Isles. Petrological studies confirm the environment of deposition, and suggest that the sediment was predominantly derived from metamorphic basement, although there was also reworking of Jurassic sediments. The source was probably the Lewisian to the west of the Minch Fault; the progression in clay and heavy mineral assemblages suggests, unroofing of less deeply weathered material with time.