Engineering geological significance of relict periglacial activity in South and East Devon

摘要

Quaternary glacial ice barely impinged on SW England with the maximum limits of the various ice advances now being reasonably well established. In SW England a probable Anglian ice front was located in Barnstaple Bay that is likely to have occupied some of the existing land surface in the area. Elsewhere the ice front does not appear to have got beyond the north coast of Devon and Cornwall, although a till has been identified on the Isles of Scilly and a possible glacial corrie has been described on Exmoor. Beyond these limits, however, the SW region will have been subject to repeated extensive and intensive periglacial activity. The effects of periglaciation will not have been removed by any subsequent ice advances, thus the region provides an excellent area to evaluate the importance of periglacial activity to engineering geology. Information on the nature and extent of periglaciation is mainly limited to detailed studies carried out in specific areas. However, the Quaternary history of SW England has recently been summarized and these summaries refer to the extent of periglacial processes. In this paper, the nature and engineering geological implications of periglacial processes and deposits from four contrasting areas of south and east Devon are discussed.