Insect faunas of the last glaciation from the Tame Valley, Warwickshire

Abstract

Lenses of peaty sand occurring at the base of terrace gravels resting upon Keuper Marl in the Tame Valley, Warwickshire, England, have yielded large numbers of insect remains. Carbon-14 dating of the organic material gives an age of 32160 +1780 -1450 y B.P. The terrace gravels are broadly correlated with Avon No. 2 Terrace and the Main Terrace of the Severn each of which has organic deposits with comparable faunas and 14 C dates. The name Upton Warren Interstadial Complex is proposed for deposits of this period. Approximately 100 fossil insect species are listed, most of which represent living forms but 26 are now extinct in Britain. A local environment acceptable to this fauna has been reconstructed; of particular interest are the climatic implications suggesting a depression of the mean July temperature of about 4 °C and a greater degree of continentality of climate than exists in Britain today. An attempt is made to estimate the likely annual range of mean monthly temperatures from these data, a mean annual temperature of about – 2 °C is suggested. These climatic conclusions provide a means of reconciling the apparently conflicting association of contemporaneous involution of the deposits, possibly indicating subzero mean annual temperatures, with an insect fauna which is clearly not typically arctic and indicating, at most, subarctic conditions.