Abstract
Sediment cores from 13 lakes in a 1500 km transect along the eastern North American Arctic contain up to four superposed stratified interglacial units. All 13 lakes contain one unit with sediment similar in character and mass to Holocene gyttja, with 14C ages >40 ka, luminescence ages 90 to 120 ka, and pollen assemblages that require nearly complete Laurentide deglaciation, supporting a Last Interglacial (LIG; MIS 5e) age. Two lakes preserve an older interglacial, with luminescence ages suggesting an MIS 7 age. Four adjacent lakes record a thin, stratified organic unit between the LIG and Holocene units with 14C ages >50 ka, that is probably from late in MIS 5. Temperature estimates from biotic proxies suggest LIG summer temperatures 4–6°C above mid-20th century values; pollen, chironomids and DNA document a poleward expansion of woody plants and invertebrate species during the LIG, supporting arguments that positive feedbacks native to the Arctic amplified insolation-driven summer temperature increases. The stratigraphic succession implies the Laurentide Ice Sheet remained intact with sea level below -40 m from ~115 ka to ~11 ka, and places new constraints on the interpretation of cosmogenic radionuclide inventories in erratic boulders older than the Holocene throughout this region.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 979-1005 |
| Number of pages | 27 |
| Journal | Journal of Quaternary Science |
| Volume | 37 |
| Issue number | 5 |
| DOIs | |
| State | Published - Jul 2022 |
Bibliographical note
Funding Information:We acknowledge the permission granted to us by the Qikiqtani Inuit to access their Baffin Island homeland for this research, and for their generous advice, assistance and friendship over the past 30 years. Likewise, the people of Kalaallit Nunaat (Greenland) have generously granted us access to their homeland. We also recognise assistance from many graduate and undergraduate students, acknowledged in the individual publications synthesised here, in the field and in our laboratories. The fieldwork that led to the acquisition of the sediment cores described herein, and the analyses that we report, were chiefly sponsored by the US National Science Foundation (NSF), through the Offices of Polar Programs and Atmospheric Sciences, and from sources within the Canadian Government. Initial support that was instrumental in Baffin Island lake‐coring was through the PALE (Paleoclimate from Arctic Lakes and Estuaries) initiative at NSF. Significant support came from NSF awards 9122974, 9402657, 9503279, 9526384, 9708418, 9809795, 0455025, 0909347, 1107411, 1108306, 1454734, 1737716, 1652274 and 1737712. Polar Continental Shelf Project, Government of Canada, provided essential logistical air support. Additional support came from other sources awarded directly to individual authors. All support is gratefully acknowledged.
Funding Information:
We acknowledge the permission granted to us by the Qikiqtani Inuit to access their Baffin Island homeland for this research, and for their generous advice, assistance and friendship over the past 30 years. Likewise, the people of Kalaallit Nunaat (Greenland) have generously granted us access to their homeland. We also recognise assistance from many graduate and undergraduate students, acknowledged in the individual publications synthesised here, in the field and in our laboratories. The fieldwork that led to the acquisition of the sediment cores described herein, and the analyses that we report, were chiefly sponsored by the US National Science Foundation (NSF), through the Offices of Polar Programs and Atmospheric Sciences, and from sources within the Canadian Government. Initial support that was instrumental in Baffin Island lake-coring was through the PALE (Paleoclimate from Arctic Lakes and Estuaries) initiative at NSF. Significant support came from NSF awards 9122974, 9402657, 9503279, 9526384, 9708418, 9809795, 0455025, 0909347, 1107411, 1108306, 1454734, 1737716, 1652274 and 1737712. Polar Continental Shelf Project, Government of Canada, provided essential logistical air support. Additional support came from other sources awarded directly to individual authors. All support is gratefully acknowledged.
Publisher Copyright:
© 2022 John Wiley & Sons, Ltd.
Keywords
- Arctic
- Arctic amplification
- Baffin Island
- lakes
- Last Interglacial
Continental Scientific Drilling Facility tags
- VASTB
- NWG14