NIVATION FORMS AND PROCESSES IN UNCONSOLIDATED SEDIMENTS, NE GREENLAND

In the periglacial unconsolidated sediment landscape of Zackenberg in High Arctic NE Greenland, perennial and seasonal snowpatches dominate the geomorphological development in large areas and control the distri bution of the vegetation. The existence and distribution of snowpatche s and their associated landforms are mainly controlled by the dominati ng winter wind direction and the amount of snow precipitation, with as pect exerting much less influence. This makes them an important source of information on past environmental change, and knowledge of the com bination of geomorphological processes and forms that result from thei r existence is thus essential. The main nivation processes are backwal l failure, sliding and flow, niveo-aeolian sediment transport, supra- and ennival sediment flows, niveo-fluvial erosion, development of pron ival stone pavements, accumulation of alluvial fans and basins, and pr onival solifluction. The importance of failure, sliding and flow in th e continuous retrogressive extension of nivation hollows and niches is emphasized under the term backwall failure. A morphological assemblag e of landforms clearly demonstrates the direct nival sediment transfer link between the eroded nivation hollows, their associated meltwater eroded channels and the pronival alluvial fans or basins. All landform elements and their formative processes are integrated into a comprehe nsive model. (C) 1998 John Wiley & Sons, Ltd.