Contrasting glacial/interglacial regimes in the western Arctic Ocean as exemplified by a sedimentary record from the Mendeleev Ridge

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

“…The input of ice-rafted debris (IRD) allows reconstruction of ice sheet dynamics, ice source, and iceberg-melt location (Ruddiman, 1977;Bond and Lotti, 1995;Hemming, 2004). The marine record of Eurasian glacial episodes (e.g., Spielhagen et al, 2004;Sejrup et al, 2005;Toucanne et al, 2009;Obrochta et al, 2014;L€ owemark et al, 2016) and geophysical mapping (e.g., Polyak et al, 2001Polyak et al, , 2004Jakobsson et al, 2010;Niessen et al, 2013;Dove et al, 2014), indicate differences between the LGM and PGM glaciations, with suggestions that the PGM/MIS 6 glaciation was one of the more extensive glacial episodes. Conversely, IRD from North America (Hudson Strait) does not seem to have reached the North Atlantic IRD belt during the penultimate glacial cycle (Obrochta et al, 2014), while it still occurred in the Labrador Sea, in close proximity to the eastern North American margin (Channell et al, 2012).…”

Methods

“…Previous coring in the deep Arctic Ocean has yielded abundant data on ostracodes from the last few glacial and interglacial cycles of the Quaternary (Cronin et al, 1994(Cronin et al, , 1995Polyak et al, 2004). These studies show that ostracodes are highly sensitive to oceanographic changes related to Arctic water mass and seaice conditions.…”

“…Shallow-water, high-latitude benthic foraminifers from Baffin Island, Greenland, and the North Sea have been extensively studied by Feyling-Hanssen and colleagues (e.g., Feyling-Hanssen et al, 1983;Feyling-Hanssen, 1990;Knudsen and Asbjørnsdottir, 1991). Quaternary calcareous foraminifers from central Arctic Ocean deep-sea cores have been studied by Scott et al (1989), Ishman et al (1996), and Polyak et al (2004). Taken together, calcareous benthic foraminifers provide a means to correlate Pleistocene sediments from the central Arctic Ocean with those from adjacent regions.…”

Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

“…Marine sediments deposited during the last glacial maximum are uncommon in the central Arctic Ocean due to the extensive sea ice and ice shelf cover. For example, Polyak et al (2004) documented a hiatus between 19 and 13 ka in several cores from the western Arctic. In a compilation of 199 new and published calibrated radiocarbon dates from the central Arctic Ocean, Poirier et al (2012) found similar results: no dates at 21-22 ka, 4 total from 19 to 15 ka, 4 dates from 14 to 15 ka, 5 dates from 13 to 14 ka, and a spike up to 13 dates between 12 and 13 ka.…”

“…It is especially important to investigate the SLR history of this region in light of recent submarine geophysical and sediment core evidence for extensive ice shelf and iceberg scouring during glacial periods in Marine Isotope Stage (MIS) 6, 4, and 2. Submarine evidence comes from across much of the Arctic Ocean, including the Hovgaard RidgeArctic Ocean (Arndt et al, 2014), the Beaufort Sea (Engels et al, 2008), the Chukchi Sea (Polyak et al, 2007; and East Siberian Sea (Niessen et al, 2013) margins, Lomonosov Ridge, the Arlis Plateau, and the slope off Herald Canyon in the East Siberian Sea (Jakobsson et al, 2010(Jakobsson et al, , 2016. These new glacial discoveries suggest the need for a reevaluation of basic assumptions that underpin sea level reconstructions based on geophysical models, marine planktic and benthic oxygen isotopes, and coral reefs.…”