Local glaciation in West Greenland linked to North Atlantic Ocean circulation during the Holocene

Abstract

Recent observations indicate that ice-ocean interaction drives much of the recent increase in mass loss from the Greenland Ice Sheet; however, the role of ocean forcing in driving past glacier change is poorly understood. To extend the observational record and our understanding of the ocean-cryosphere link, we used a multi-proxy approach that combines new data from proglacial lake sediments, 14 C-dated in situ moss that recently emerged from beneath cold-based ice caps, and 10 Be ages to reconstruct centennial-scale records of mountain glacier activity for the past ~10 k.y. in West Greenland. Proglacial lake sediment records and 14 C dating of moss indicate the onset of Neoglaciation in West Greenland at ca. 5 ka with substantial snowline lowering and glacier expansion at ca. 3.7 ka followed by additional ice expansion phases at ca. 2.9, ca. 1.7, and ca. 1.4 ka and during the Little Ice Age. We find that widespread glacier growth at ca. 3.7 ka in West Greenland coincides with marked cooling and reduced strength of the West Greenland Current in Disko Bugt. The transition to cooler ocean conditions at ca. 3.7 ka identified in Disko Bugt is registered by marine proxy data farther afield in East Greenland and on the northwestern Icelandic shelf, implying large-scale paleoceanographic changes across the North Atlantic during this interval. The similarity between glacier change on West Greenland and multiple marine and terrestrial records across the North Atlantic suggests that glaciers are strongly influenced by changes in ocean circulation and consequently implies that the ocean-cryosphere teleconnection is a persistent feature of the Arctic system.

Quantifying Provenance and Transport Pathways of Holocene Sediments From the Northwestern Greenland Margin

“…During the late Holocene, glacier growths were observed in West Greenland following the regional Holocene Thermal Maximum (Briner et al, 2016; Schweinsberg et al, , ), while in core 204, an increase of very coarse silt concentration (Figure f) and of the presence of IRDs (Figure ) was observed after 4.8 cal ka BP. Interestingly, the highest contribution of basalts (WGMC#2, up to 30 wt.%) in core 204 is found between 2.0 and 2.4 cal ka BP, at the same time as a relatively high sea‐ice cover duration (~7 months/year; Caron, Rochon, et al, 2019) and a peak of reworked palynomorphs and freshwater indicator Halodinium (Figure g).…”

Local ice caps in Finderup Land, North Greenland, survived the Holocene Thermal Maximum

“…Lake records from two other studies from Sukkertoppen Iskappe in southwest Greenland and a local ice cap at Nuussuaq in west Greenland were less conclusive (Schweinsberg et al . , ). The Sukkertoppen Iskappe and the local ice cap on Nuussuaq were smaller than at present from ~9.0 to 5.0 cal.…”

“…In southwest Greenland, proglacial lake records also demonstrate that three local ice caps completely melted away during the HTM and that their formation during the Neoglacial was controlled by their respective altitudes (Larsen et al 2017). Lake records from two other studies from Sukkertoppen Iskappe in southwest Greenland and a local ice cap at Nuussuaq in west Greenland were less conclusive (Schweinsberg et al 2017(Schweinsberg et al , 2018. The Sukkertoppen Iskappe and the local ice cap on Nuussuaq were smaller than at present from 9.0 to 5.0 cal.…”

Evolution of sea‐surface conditions on the northwestern Greenland margin during the Holocene

“…Regionally, the Late Holocene is characterized by a cooling trend which corresponds to the neoglacial period associated with glacier growth and subsurface cooling along the west Greenland coast (e.g., Briner et al, 2016;Perner et al, 2013;Schweinsberg et al, 2017). This neoglacial cooling period has been recorded over the last ca.…”