The timing of coversand deposition in northwest Norfolk, UK: a cautionary tale

摘要

Coversand deposits, consisting largely of reworked fluvial and glaciofluvial sediments, blanket the landscape in discrete areas of northern and eastern England. A newly discovered zone of coversand deposits has been found in northwest Norfolk, which shows stratigraphic evidence of episodic sand accretion. The presence of involutions within the coversand at Leziate signifies the occurrence of post-depositional periglacial activity. Infra-red stimulated luminescence (IRSL) dating of feldspars has been undertaken on five samples from four sites within the new coversand zone. Three of the samples were insufficiently zeroed at deposition to provide accurate dates for deposition of the sand sheets, challenging the assumption that coversands are all well bleached, with consequent implications for existing thermoluminescence (TL) dates on UK coversands. An IRSL age of 12,825 +/- 1910 yr for well-bleached sands at Leziate shows that sand accretion occurred during the period of rapid climate transition at the end of the Last Glacial. Late Holocene aeolian activity resulted in sand emplacement at Ling Common. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 35]