Abstract

Three separate till units are recognized on Orkney deposited during the last ice sheet glaciation: the Digger, Scara Taing and Quendal Till members. The Digger Till records an ice advance from the south that extended on to the Atlantic shelf. The Scara Taing Till records a later period of full ice cover when ice moved from the SE out of the Moray Firth and reached Last Glacial Maximum (LGM) limits on the shelf edge. The Quendal Till records a late phase of ice sheet flow from the SE to limits c. 20 km west of Orkney. No till unit or flow set has been identified to confirm the presence of a local ice cap on southern Orkney during the last glaciation. Whilst the blocking presence of the Fennoscandian Ice Sheet (FIS) and the Shetland Ice Cap may have contributed to the deflection of ice flow over Orkney, similar flow patterns also occurred before and after the LGM. Scandinavian erratics on northern Orkney are probably reworked and provide no direct support for the passage of the FIS. Middle to Late Carboniferous palynomorphs found in tills in eastern Orkney may have been reworked from nearby Permian mudstones.

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