The Quaternary deposits of the Ballaugh and Kirkmichael districts, Isle of Man

Abstract

During the Last Glaciation ice advanced against the Isle of Man from the north, depositing in the north-west of the island large amounts of drift up to an altitude of 150 ft, and smaller isolated amounts of drift up to an altitude of 650 ft. These deposits are well seen in section at Orrisdale Head, and are described as an Orrisdale Series of deposits. Much of the island projected above the ice of the Last Glaciation as a nunatak. In the coastal cliffs west of Kirkmichael another series of drifts, also derived from the north, is seen below the Orrisdale Series, and since these drifts are similar to the glacial deposits of Gipping age known farther south in the Irish Sea basin, they are regarded as Gipping in age. They are well exposed at Jurby Head and at Ballateare, and are described as a Ballateare Series. The whole island may have been overridden by ice during the Gipping Glaciation. During the retreat of the Orrisdale ice, marginal lakes, outwash fans, and morainic ridges were formed. Late-glacial deposits accumulated in enclosed basins on the ridges, and these have been given carbon-14 dates ranging from 10 200 to 8300 b.c . When the permafrost melted at the end of late-glacial time, large quantities of sand and gravel, which had been built up into terraces in a marginal lake impounded in Glen Wyllin, south of Kirkmichael, were set free. These sands and gravels moved down and built up an early post-glacial alluvial fan at the mouth of the Glen, burying the late-glacial deposits to a depth of 40 ft.