Quaternary geology of the area between Frederikshåbs Isblink and Ameralik

Abstract

The margin of the Inland lce between Frederikshåbs Isblink and Ameralik is nearly stationary. An estimate of the average ablation is higher here than that reported from Disko Bugt 700 km farther north. The Pleistocene history of this area indicates at least one complete glaciation of the coastland with the Inland lce cover reaching to the offshore banks. This must predate or be contemporaneous with the Early Wisconsin. Recession of the Inland lce margin behind the extent of the Frederikshåbs Isblink took place around 22000 RP. Undisturbed shell beds at Sanerata tima with an age of 13 380 B.P. indicate the possibility that parts of the outer coasts were ice-free during the Late Wisconsin. In the early parts of the Holocene time there was a recession of the Inland Ice from the coastland. The most important moraine stage is here dated to 8300 B.P. (the Fjord stage) and in a small sector at Marraq - Sanerata tima this stage marks the maximum extent of the Inland Ice during the Late Wisconsin. The Holocene recession continued beyond the present extent of the Inland Ice, and subsequent stabilisation took place, presumably at 6000-5000 B.P., involving limited sectorial readvances. It is possibie that the lobe of Frederikshåbs Isblink was first formed during this stabilisation.