Rapid Ice-Sheet Growth and Initiation of the Last Glaciation

• Published in: Quaternary Research
• Main Authors: Johnson, R.G., Andrews, J.T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1979
• Subjects: Baffin Bay; Baffin Island; Barents Sea; Greenland; Norwegian Sea; Baffin; Fennoscandian; Ice Sheet; North Atlantic
• Online Access: http://dx.doi.org/10.1016/0033-5894(79)90093-0; http://api.elsevier.com/content/article/PII:0033589479900930?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:0033589479900930?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400030155

Calculations based on temperature-corrected oxygen-isotope ratios from deep-sea cores yield a glacioeustatic sea-level fall in excess of 50 m during the first 10,000 yr of the last glaciation, and generally support the local regression of about 70 m inferred from tectonically rising New Guinea beaches. We propose that this rapid glacial buildup depended on high-latitude cooling, and large increases of high-latitude regional winter precipitation in the Laurentide and the Fennoscandian-Barents Sea areas, and that these factors were caused by a critical alteration of North Atlantic Drift currents and their associated subpolar atmospheric circulation. In support of this, faunal data from northeast North Atlantic deep-sea cores show that the glacial buildup was accompanied by a sudden loss of most of the North Atlantic Drift from the Greenland-Norwegian Sea, a factor favoring reduced heat input into the higher latitudes. Subpolar mollusk and foraminifera fauna from elevated marine deposits on the Baffin Island coast, and northwest North Atlantic core data suggest a continuation or an associated restoration of subpolar water west of Greenland as far north as Baffin Bay, a factor favoring precipitation in the northeast Canadian region. Heat transport and atmospheric circulation considerations suggest that the loss of the northeast North Atlantic Drift was itself a major instrument of high-latitude climate change, and probably marked the initiation of major new ice-sheet growth.