Lateglacial to Holocene palaeoenvironmental change in the Muck Deep, offshore western Scotland

Shelf basins (‘glacial incisions’) can preserve a detailed record of fine palaeoclimatic changes due to their low-energy environment. The ‘Muck Deep’, a complex of glacially-overdeepened troughs on the Inner Hebrides shelf constitutes an example of such environments.
Five sediment cores from the basin, have been analysed and related to the local geomorphology and sub-surface seismic facies. The cores show an integrated sequence of sedimentary and faunal variations from the retreat of ice (~17 ka) to the present day. Glacimarine sandy muds with ice rafted debris are dated to about 11.7 cal ka BP, supporting glacial occupancy in western Scotland until the latest stages of GS-1. The transition from a paraglacial to a more stable, vegetated landscape is indicated by an erosional boundary dated between 10.8 and 11.3 cal ka BP. A sandy deposit at 200 m depth in the southern Muck Deep shows two upward-fining cycles and a mid-core erosional unconformity interpreted as bottom-current deposits. Such structures do not occur in the western Muck Deep, indicating different bottom current velocities through time. A regional signal of increasing current energy at the end of the Holocene marine transgression, is interpreted as the onset of modern oceanographic conditions.