A Compilation of Radiocarbon Dates from Disko Bugt, Central West Greenland/Meteorological Observations in 1996 at the Arctic Station, Qeqertarsuaq (Godhavn), Central West Greenland/A Discussion on Pingos in Mellemfjord, Disko, Central West Greenland/Open System Pingos in Mellemfjord, Disko, Central West Greenland: A Reply to Gurney and Worsley

Abstract

188 new and previously published radiocarbon dates on Holocene material from Disko Bugt, central West Greenland, are presented together with relevant informations (laboratory number, place name, dated material, geografic coordinates, altitude and δ13C-value) about the dates. In October 1990 an automatic weather station was established at the Arctic station (65 °15′N,53 °31′W), Qeqertarsuaq (Godhavn), Central West Greenland. The Station register parameters each 20 min., and the parameters have been described in an earlier paper in this journal by Nielsen et al. (1995). The present paper summarises main points of the climate during 1996. Open system, or more correctly, hydraulic pingos, are genetically poorly understood. A continuing problem concerns their need for a perennial groundwater supply (intra- or sub-permafrost). This has to be maintained despite the existence of continuous permafrost in many areas where they are located. Recent work on Disko Island has suggested a new type of hydraulic pingo developing only in a “marsh environment”. It is argued that the marsh setting is not relevant to the formation of these features and that they are simply hydraulic pingos. A group of marsh initiated open system pingo remnants from the Iterdlagssûp kûgssua valley mouth, in Mellemfjord, Disko Island, Central West Greenland was described in Christiansen (1995). Gurney and Worsley (1997) state that the location of this group of pingo remnants in the Iterdlagssûp kûgssua valley mouth is of no relevance to their genesis, and that they presumably were the result of an assumed late Holocene sea level regression, causing permafrost to be established in the valley bottom. In this reply the arguments by Gurney and Worsley (1997) on the Iterdlagssûp kûgssua valley pingos are commented, and it is argued by way of sea level information, frost penetration and water supply that the special setting must indeed have caused pingo initiation and growth. Furthermore, the area has experienced a relative sea level rise during the late Holocene.