CONTRASTING GLACIMARINE SEDIMENTARY ENVIRONMENTS OF 2 ARCTIC FJORDS ON DISKO, WEST GREENLAND

Two fiords, Kangerluk and Akulliit, on the island of Disko, central We st Greenland have very different sedimentary regimes caused by differe nces in the characteristics of their drainage basins and in the exposu re of their waters to the open sea of Baffin Bay. Their insular locati on also results in much lower input of water and sediment than in near by fiords on the mainland of Greenland that are affected by glaciers f rom the Greenland Ice Cap, Akulliit has a small drainage basin and low input of water and sediment; it is directly exposed to the higher ene rgy wave environment of Baffin Bay. As a consequence, the mean thickne ss of Holocene glacimarine sediment assessed in acoustic records is le ss than 6 m in the inner and middle reaches of the fiord (mean Holocen e accumulation, 0.4 mm/a) and about 11 m (1 mm/a) near the mouth. Date d core sediment indicates that rates are less than 0.5 mm/a in the out er fiord in the last 2 ka. The larger, more glacier-covered drainage b asin of Kangerluk contributes much larger loads of sediment to a fiord environment protected from the open sea, As a result, Holocene glacim arine sediment is more than 80 m thick in the inner fiord (mean Holoce ne accumulation up to 5 mm/a), decreasing to 10-40 m (about 1 mm/a) in the middle reaches. Accumulation rates in Kangerluk are within the ra nge of arctic fiords, including those of Baffin Island, but those in A kulliit are near the lower limit. The decrease in thickness distally i n Kangerluk is typical of arctic fiords, but the opposite trend in Aku lliit is probably due to erosion and re-distribution of sediment in th e higher energy environment there. (C) 1998 Elsevier Science B.V. All rights reserved.