Early to middle Holocene valley glaciations on northernmost Greenland

• Published in: Quaternary Science Reviews
• Main Authors: Möller, Per, Larsen, Nicolaj Krog, Kjær, Kurt H., Funder, Svend Visby, Schomacker, Anders, Linge, Henriette, Fabel, Derek
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2010
• Subjects: Constable Bugt; Greenland; Johannes V. Jensen Land; Moraine Ridge; Peary; Peary Land; glacier; Johannes V. Jensen land; North Greenland; polar desert; Sea ice
• Online Access: https://curis.ku.dk/portal/da/publications/early-to-middle-holocene-valley-glaciations-on-northernmost-greenland(4dd172aa-c0ab-4727-ba0f-1588fd531cab).html; https://doi.org/10.1016/j.quascirev.2010.06.044

This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18e22 cal ka BP) into the Holocene. It records the history of a shelf-based glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine limit formed at w45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from onlapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14C dating results, the youngest ice advance phase can be narrowed down to 14C ages between w5.5e5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of w2500 years during which the north coast of Greenland e as opposed to today e experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose ...