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

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 14C ages on 37 samples of mollusc shells from various sites on the islands. Most samples yielded ages in the range of 48–26 14C Ky. Such old samples are sensitive to contamination by young 14C, 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 14C 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 14C 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 0oC, and for less than 10 000 years if it was −5oC.

Pink marine sediments reveal rapid ice melt and Arctic meltwater discharge during Dansgaard–Oeschger warmings

“…The present study provides clear evidence of a significant northern component to the millennial timescale sea-level changes. Our observations also support emerging evidence of a much more dynamic Eurasian ice sheet than previously recognized, with retreat and advance closely linked to the Greenland interstadials and stadials 39,40 .…”

“…During MIS 4, c. 70-60 kyr BP, the Barents-Kara Sea (including Svalbard) and Scandinavia were covered by a huge confluent ice sheet [37][38][39][40][41] . The glaciation was followed by a rapid deglaciation, and from c. 55 to 25 kyr BP, the ice sheets on Svalbard and Scandinavia were apparently separated by an ice-free Barents Sea 37,40,41 . During the warmest period of MIS 3, 40-35 kyr BP, the Scandinavian ice sheet was most likely limited to the central part of Norway and Sweden 39,41 .…”

“…The evidence is lacking in temporal ARTICLE resolution, but two rapid advances beyond the coastline of Norway seem well-documented 39,40,43 . The first advance is correlated with Greenland interstadial 10 and dated to B41 kyr BP on the GICC05 timescale.…”

Past ice-sheet flow east of Svalbard inferred from streamlined subglacial landforms

“…2), but it does not necessarily preclude the presence of an additional ice dome southeast of Kong Karls Land in the Barents Sea. We have no evidence for such a dome, and the relatively low Holocene raised shorelines on Novaya Zemlya do not imply the presence of thick LGM ice farther east (Mangerud et al, 2008). There must have been an ice crest somewhere in the Barents Sea, probably located over the shallow Storbanken (~78°N).…”

“…Forman et al (2004) concluded that the pattern of postglacial emergence around the Barents Sea implied that the maximum ice load during the late Weichselian was located over the northern Barents Sea and eastern Svalbard. In addition, raised beaches of Holocene age in Novaya Zemlya are only 10-18 m above sea level, implying that LGM ice was thin here (Mangerud et al, 2008). On Franz Josef Land the maximum Holocene raised beaches are at 49 m (Forman et al, 1996), also suggesting that the greatest LGM ice loading was in the northwestern Barents Sea.…”