The timing of last-glacial periglacial and aeolian events,Twente, eastern Netherlands

Sequences of last-glacial age contain valuable palaeoclimatic information but are often difficult to date because the environment has been unfavourable for deposition of datable organic material. This paper presents age-estimates, determined by optically stimulated luminescence, for sediments from the type site of the so-called ‘coversands’ (periglacial aeolian deposits) in The Netherlands. These improve the chronology of this type site considerably, allowing age limits (22–17 kyr BP) to be set, for the first time, for the important phase of widespread permafrost degradation and aeolian deflation recorded in these deposits. Aeolian deposition occurred intermittently for most of the Last Glacial Maximum and the Late-glacial phases. Based on luminescence dating, sand-sheet deposition was concentrated between ca. 17–14 kyr ago, and dune formation was dominant during the Younger Dryas. The Younger Dryas was sufficiently cold to allow the first stages of ice-wedge-cast development in The Netherlands. Copyright © 1999 John Wiley & Sons, Ltd.