Ice-free conditions in Novaya Zemlya 35,000 to 30,000 cal years BP, as indicated by radiocarbon ages and amino acid racemization evidence from marine molluscs

Mangerud, Jan and Kaufman, Darrell and Hansen, Jesper and Svendsen, John Inge (2008) Ice-free conditions in Novaya Zemlya 35,000 to 30,000 cal years BP, as indicated by radiocarbon ages and amino acid racemization evidence from marine molluscs. Polar Research, 27 (2). pp. 187-208. ISSN 1751-8369

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Abstract

Novaya Zemlya was covered by the eastern part of the Barents-Kara ice sheet during the glacial maximum of marine isotope stage 2 (MIS 2). We obtained (14)C ages on 37 samples of mollusc shells from various sites on the islands. Most samples yielded ages in the range of 48-26 (14)C Ky. Such old samples are sensitive to contamination by young (14)C, and therefore their reliability was assessed using replicate analyses and amino acid geochronology. The extent of aspartic acid racemization (Asp D/L) indicates that many of the (14)C ages are correct, whereas some are minimum ages only. The results indicate that a substantial part of Novaya Zemlya was ice-free about 35-27 (14)C Kya, and probably even earlier. Corresponding shorelines up to > 140 m a.s.l. indicate a large Barents-Kara ice sheet during early MIS 3. These results are consistent with findings from Svalbard and northern Russia: in both places a large MIS 4/3 Barents-Kara ice sheet is postulated to have retreated about 50 Kya, followed by an ice-free interstadial that lasted until up to ca. 25 Kya. The duration of the MIS 2 glaciation in Novaya Zemlya was calculated by applying the D/L values to a kinetic equation for Asp racemization. This indicates that the islands were ice covered for less than 3000 years if the basal temperature was 0(o)C, and for less than 10 000 years if it was -5 degrees C.

Item Type:	Article
ID number or DOI:	10.1111/j.1751-8369.2008.00064.x
Keywords:	Amino acid racemization; Barents Sea ice sheet; eastern svalbard; Eurasian ice sheet; Holocene; kara seas; kyr bp; Last Glacial Maximum; Last Glacial Maximum; Marine molluscs; postglacial emergence; Russia; sea-level history; sheet; Spitsbergen
Subjects:	Q Science > QE Geology
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	College of Engineering, Forestry, and Natural Science > School of Earth Sciences and Environmental Sustainability
Date Deposited:	21 Oct 2015 22:39
URI:	http://openknowledge.nau.edu/id/eprint/1679

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