Abstracts of Symposium 55 and some papers from other related Symposia.

The Loess of Britain: Distribution, Stratigraphy and Origin

John A. CATT, IACR-Rothamsted, Harpenden, Herts, AL5 2JQ, England

Loess > 1 m covers only 0,4% of the area of England, occurring mainly in north Kent, south-east Essex and the west Sussex coastal plain. However, soil mapping by the Soil Survey and Land Research Centre (previously Soil Survey of England and Wales), which offers complete coverage of England and Wales at 1:250,000 scale and more detailed information at 1:25,000 - 1:63,360 scales for about 25% of the country, shows that very thin loess (30-100 cm) occupies a further 12,7% of England and Wales. These surface deposits are entirely Late Devensian (TL ages of 10-25 ka), and their mineralogical compositions shows that they are mainly derived from glacial outwash deposits of the southern North Sea basin. However, some minor occurrences in the extreme west have a mineralogically different silt component, which is probably from outwash in the Irish Sea area. In south-east England the loess overlies various substrata, but the isolated patches in western and northern areas are confined to limestone and other Ca-rich bedrock surfaces. An originally more extensive cover all Late Devensian loess was irregularly eroded by Late Devensian gelifluction and Holocene collaviation and fluvial activity; preservation on limestone surfaces is attributed to an earlier episode of secondary carbonate cementation. Isolated pockets of older loess, with TL age estimates usually of 100-150 ka, are quite widespread in south-east England. The most extensive are on gravel terraces of the River Avon in the New Forest, south-west Hampshire. These suggest the earlier existence of a Wolstonian loess sheet of similar thickness and extent to the Late Devensian loess, which was even more extensively eroded before the Late Devensian. Some pockets (e.g. infilled dolines) are associated with Paleolithic industries. The Wolstonian loess is mineralogically different from the Devensian, but it has been more strongly weathered and its origin is uncertain. A yet older (Anglian?) loess is known from at least three sites.

	Back to the Table of Content
	Back to the Abstracts list