Late Quaternary stratigraphy and sedimentation patterns in the western Arctic Ocean

Polyak, Leonid; Bischof, Jens; Ortiz, Joseph D.; Darby, Dennis A.; Channell, James E T; Xuan, Chuang; Kaufman, Darrell S.; Løvlie, Reidar; Schneider, David; Eberl, Dennis D.; Adler, Ruth E

doi:10.1016/j.gloplacha.2009.03.014

Cited by 154 publications

(164 citation statements)

References 79 publications

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“…Recent geophysical mapping in the Arctic, however, has led to a re-evaluation of large floating Arctic ice shelves during the Pleistocene. Various mechanisms have been proposed to account for the mapped submarine features, including the drifting of ice-shelf remnants or mega-bergs trapped in multi-year sea ice, or a transient surge or brief grounding of a floating ice shelf (Polyak et al, 2001(Polyak et al, , 2009Engels et al, 2008;Dowdeswell et al, 2010;O'Regan et al, 2010;Gebhardt et al, 2011;Niessen et al, 2013;Dove et al, 2014). Age control for many of the features remains enigmatic, often relying on stratigraphic correlation and biostratigraphy; for example, identification of diagnostic MIS 5e nannofossils gives a likely, or minimum, MIS 6 age estimate for features on Morris Jesup Rise, Lomonosov Ridge, Yermak Plateau, Hovgaard Ridge, Mendeleev Ridge, and Arlis Plateau (Jakobsson, 1999;Polyak et al, 2001;Matthiessen and Knies, 2001;Kristoffersen et al, 2004;Spielhagen et al, 2004;Jakobsson et al, 2008Jakobsson et al, , 2010Jakobsson et al, , 2016Arndt et al, 2014;L€ owemark et al, 2016).…”

Section: The Global D 18 O:sea-level/ice-volume Relationshipmentioning

confidence: 99%

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

Rohling

Hibbert

Williams

et al. 2017

Quaternary Science Reviews

100

115

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Arctic ice shelf Last Interglacial Glacioisostatic adjustment a b s t r a c t Studies of past glacial cycles yield critical information about climate and sea-level (ice-volume) variability, including the sensitivity of climate to radiative change, and impacts of crustal rebound on sealevel reconstructions for past interglacials. Here we identify significant differences between the last and penultimate glacial maxima (LGM and PGM) in terms of global volume and distribution of land ice, despite similar temperatures and radiative forcing. Our analysis challenges conventional views of relationships between global ice volume, sea level, seawater oxygen isotope values, and deep-sea temperature, and supports the potential presence of large floating Arctic ice shelves during the PGM. The existence of different glacial 'modes' calls for focussed research on the complex processes behind ice-age development. We present a glacioisostatic assessment to demonstrate how a different PGM ice-sheet configuration might affect sea-level estimates for the last interglacial. Results suggest that this may alter existing last interglacial sea-level estimates, which often use an LGM-like ice configuration, by several metres (likely upward).

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Section: The Global D 18 O:sea-level/ice-volume Relationshipmentioning

confidence: 99%

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

Rohling

Hibbert

Williams

et al. 2017

Quaternary Science Reviews

100

115

View full text Add to dashboard Cite

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“…The sediments in 01A-GC and in the Holocene part of 05JPC/TC (0-1300 cm) and 06JPC (0-935 cm) consist predominantly of homogeneous clayey silt (fine-grained unit). This unit of cores 05JPC and 06JPC is underlain by a more complex lithostratigraphy with laminations and coarse ice-rafted debris indicative of glaciomarine environments affected by glacial/deglacial processes ("glaciomarine unit"; McKay et al, 2008;Lisé-Pronovost et al, 2009;Polyak et al, 2009).…”

Section: Coring and Samplingmentioning

confidence: 99%

Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

et al. 2017

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Abstract. The Beaufort Gyre (BG) and the Bering Strait inflow (BSI) are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz / feldspar and chlorite / illite ratios in three sediment cores from the northern Chukchi Sea, providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz / feldspar ratio, interpreted as a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with an orbitally controlled decrease in summer insolation. We propose that the BG rotation weakened as a result of the increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz / feldspar ratio (the BG circulation) is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximation by the chlorite / illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified in a proxy-based BSI record characterized by the highest age resolution.

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“…The most likely candidate for this is shoaling of isolated water in the deep central Arctic Ocean (see SOM), connected to the Nordic Seas via Fram Strait, with a volume of ~1.2 x 10 7 km 3 below 1 km water depth (22), approximately four times greater than the deep (>1 km) Nordic Seas. Because the Arctic Ocean (and AM as a whole) is a semi-enclosed basin, that was further restricted during the last glacial with the closure of the Bering Strait, it was susceptible to isolation and the development of a poorly ventilated water mass.Previous studies have suggested that there was thick ice-cover across much of the Arctic during the last glacial maximum, leading to minimal or no sedimentation in the central Arctic of either terrigenous or biogenic material (20,23). With no appreciable surrounding continental shelf area there was probably also only a minor contribution to the deep from brine-enhanced shelf water (24).…”

mentioning

confidence: 99%

“…2 and Supporting Online Materials and Methods, SOM). Core sites from within the central Arctic were not chosen because of the low abundance of benthic foraminifera, and the extremely low glacial sedimentation rate (20) would further increase the uncertainty in the stratigraphic age of samples, and hence the reconstruction of  14 C. Table 1 and Fig. 2 show that, in contrast to the well ventilated deep waters and small benthic-planktic (B-P) 14 C offset (~100 years) of the Holocene and present day, much of the late glacial and deglacial Norwegian Sea was characterized by extremely poorly ventilated deep waters, with benthic ventilation ages of ~7000-10,000 years (and B-P 14 C offsets of a similar magnitude).…”

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confidence: 99%

A warm and poorly ventilated deep Arctic Mediterranean during the last glacial period

Thornalley

Bauch

Gebbie

et al. 2015

Science

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Changes in the formation of dense water in the Arctic Ocean and Nordic Seas (the 'Arctic Mediterranean', AM) likely contributed to the altered climate of the last glacial period. We examine past changes in AM circulation by reconstructing 14 C ventilation ages of the deep Nordic Seas over the last 30,000 years. Our results show that the deep glacial AM was extremely poorly ventilated (ventilation ages of up to 10,000 years). Subsequent episodic overflow of aged water into the mid-depth North Atlantic occurred during deglaciation. Proxy data also suggest the deep glacial AM was ~2-3°C warmer than modern; deglacial mixing of the deep AM with the upper ocean thus potentially contributed to melting sea-ice and icebergs, as well as proximal terminal icesheet margins.One Sentence Summary: New proxy data reveals the extremely poor ventilation of a warmer, glacial deep Arctic Mediterranean, which overflowed into the Northeast Atlantic during the last deglaciation. Main Text:The Atlantic meridional overturning circulation (AMOC) plays an important role in Earth's climate because it redistributes ocean heat and helps control the storage of carbon in the deep ocean. The primary northern hemisphere sources of dense water supplied to the AMOC are produced in the Arctic Mediterranean (1). Here, warm surface waters from the Atlantic flow northwards and circulate around the AM via several different pathways, gradually cooling, thereby releasing heat to the atmosphere, and becoming denser. Much of this water mass transformation is thought to occur in the Nordic Seas via intermediate and deep open ocean convection, with a smaller contribution from the Arctic that also involves the addition of dense waters from brine-2 enhanced shelf water production (1, 2). The dense water produced by these processes overflows the Greenland-Scotland Ridge (GSR), ultimately forming lower North Atlantic Deep Water (NADW), as part of the deep southward return flow of the AMOC.Because of the northward heat transfer associated with the flow of warm surface water to convection sites, changes in deep water formation in the North Atlantic and Nordic Seas are thought to be associated with the altered climate of the last glacial maximum (LGM) and the abrupt climate events of the last deglaciation (~19 to 7 thousand years ago, ka), such as the northern hemisphere cold intervals Heinrich Stadial 1 (HS1) and the Younger Dryas (YD) (3-5), which affected global climate (6,7). In this study we investigate circulation changes over the past 30 ka in the deep Norwegian Sea (and by inference, the broader AM) by reconstructing radiocarbon ventilation age and deep ocean temperature. Our results reveal an absence of deep convection within the AM throughout much of the last glacial and deglaciation and instead suggest the presence of a relatively warm and extremely poorly ventilated water mass in the glacial deep AM that subsequently overflowed southward into the North Atlantic during the deglaciation.North Atlantic radiocarbon reconstructions. Several studies...

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Late Quaternary stratigraphy and sedimentation patterns in the western Arctic Ocean

Cited by 154 publications

References 79 publications

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

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

Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

A warm and poorly ventilated deep Arctic Mediterranean during the last glacial period

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