TY - JOUR
T1 - Glacial history of Inglefield Land, north Greenland from combined in situ 10Be and 14C exposure dating
AU - Søndergaard, Anne Sofie
AU - Larsen, Nicolaj Krog
AU - Steinemann, Olivia
AU - Olsen, Jesper
AU - Funder, Svend
AU - Egholm, D.L.
AU - Kjær, Kurt Henrik
PY - 2020/10
Y1 - 2020/10
N2 - Determining the sensitivity of the Greenland Ice Sheet (GrIS) to Holocene climate changes is a key prerequisite for understanding the future response of the ice sheet to global warming. In this study, we present new information on the Holocene glacial history of the GrIS in Inglefield Land, north Greenland. We use 10Be and in situ 14C exposure dating to constrain the timing of deglaciation in the area and radiocarbon dating of reworked molluscs and wood fragments to constrain when the ice sheet retreated behind its present-day extent. The 10Be ages are scattered ranging from ca. 92.7 to 6.8ka, whereas the in situ 14C ages range from ca. 14.2 to 6.7ka. Almost half of the apparent 10Be ages predate the Last Glacial Maximum and up to 89% are to some degree affected by nuclide inheritance. Based on the few reliable 10Be ages, the in situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced at ca. 8.6-8.3kacalBP in the western part and ca. 7.9ka in the central part, following the opening of Nares Strait and arrival of warm waters. The ice margin reached its present-day position at ca. 8.2ka at the Humboldt Glacier and ca. 6.7ka in the central part of Inglefield Land. Radiocarbon ages of reworked molluscs and wood fragments show that the ice margin was behind its present-day extent from ca. 5.8 to 0.5kacalBP. After 0.5kacalBP, the ice advanced towards its Little Ice Age position. Our results emphasize that the slowly eroding and possibly cold-based ice in north Greenland makes it difficult to constrain the deglaciation history based on 10Be ages alone unless they are paired with in situ 14C ages. Further, combining our findings with those of recently published studies reveals distinct differences between deglaciation patterns of northwest and north Greenland. Deglaciation of the land areas in northwest Greenland occurred earlier than in north Greenland, and periods of restricted ice extent were longer, spanning the Middle and Late Holocene. Overall, this highlights past ice sheet sensitivity to Holocene climate changes in an area where little information was available just a few years ago.
AB - Determining the sensitivity of the Greenland Ice Sheet (GrIS) to Holocene climate changes is a key prerequisite for understanding the future response of the ice sheet to global warming. In this study, we present new information on the Holocene glacial history of the GrIS in Inglefield Land, north Greenland. We use 10Be and in situ 14C exposure dating to constrain the timing of deglaciation in the area and radiocarbon dating of reworked molluscs and wood fragments to constrain when the ice sheet retreated behind its present-day extent. The 10Be ages are scattered ranging from ca. 92.7 to 6.8ka, whereas the in situ 14C ages range from ca. 14.2 to 6.7ka. Almost half of the apparent 10Be ages predate the Last Glacial Maximum and up to 89% are to some degree affected by nuclide inheritance. Based on the few reliable 10Be ages, the in situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced at ca. 8.6-8.3kacalBP in the western part and ca. 7.9ka in the central part, following the opening of Nares Strait and arrival of warm waters. The ice margin reached its present-day position at ca. 8.2ka at the Humboldt Glacier and ca. 6.7ka in the central part of Inglefield Land. Radiocarbon ages of reworked molluscs and wood fragments show that the ice margin was behind its present-day extent from ca. 5.8 to 0.5kacalBP. After 0.5kacalBP, the ice advanced towards its Little Ice Age position. Our results emphasize that the slowly eroding and possibly cold-based ice in north Greenland makes it difficult to constrain the deglaciation history based on 10Be ages alone unless they are paired with in situ 14C ages. Further, combining our findings with those of recently published studies reveals distinct differences between deglaciation patterns of northwest and north Greenland. Deglaciation of the land areas in northwest Greenland occurred earlier than in north Greenland, and periods of restricted ice extent were longer, spanning the Middle and Late Holocene. Overall, this highlights past ice sheet sensitivity to Holocene climate changes in an area where little information was available just a few years ago.
UR - http://www.scopus.com/inward/record.url?scp=85095602177&partnerID=8YFLogxK
U2 - 10.5194/cp-16-1999-2020
DO - 10.5194/cp-16-1999-2020
M3 - Tidsskriftartikel
SN - 1814-9324
VL - 16
SP - 1999
EP - 2015
JO - Climate of the Past
JF - Climate of the Past
IS - 5
ER -