Effects of Short and Long Term Climatic Changes on Permafrost - Sedimentological Data

Abstract

Permafrost or perennially frozen ground, is defined as ‘the thermal condition in soil or rock of having temperatures below 0°C persist over at least two consecutive winters and intervening summer’ (Brown and Kupsch 1974). It currently underlies approximately one fifth of the earth’s terrestrial surface. During the cold stages of the Quaternary, permafrost extended equatorwards and developed in areas which currently enjoy relatively temperate climates. Consequently it is a phenomenon which has intrinsic interest for palaeoclimatologists, yet in comparison with the prominence given to glaciological reconstructions in the generation of G.C.M.s it has received relatively little attention. This assumes, of course, that its former presence and hence extent, can be identified via the evidence provided by the geological record. It has to be conceded that this is often a more difficult task in the field than the recognition of former glaciation limits and patterns.