Arctic ice export events and their potential impact on global climate during the late Pleistocene

Abstract

[1] Ice sheets in the North American Arctic and, to a lesser extent, those in northern Eurasia calved large quantities of icebergs that drifted through Fram Strait into the Greenland Sea several times during the late Pleistocene. These icebergs deposited Fe oxide grains (45-250 mm) and coarse lithic clasts >250 mm matched to specific circum-Arctic sources. Four massive Arctic iceberg export events are identified from the Laurentide and the Innuitian ice sheets, between 14 and 34 ka (calendar years) in a sediment core from Fram Strait. These relatively short duration (<1-4 kyr) events contain 3-5 times the background levels of Fe oxide grains. They began suddenly, as indicated by a steep rise in the number of grains matched to an ice sheet source, suggesting rapid purges of ice through Fram Strait, due perhaps to collapse of ice sheets. The larger events from the northwestern Laurentide ice sheet are preceded by events from the Innuitian ice sheet. Despite the chronological uncertainties, the Arctic export events appear to occur prior to Heinrich events.

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

“…Ocean IRD events remains difficult because of generally low sedimentation rates, it has been suggested that some events sourced from the Canadian Arctic Archipelago are broadly correlative with the North Atlantic's Heinrich events (Darby et al, 2002). The possibility of large-scale ice sheet reorganisations during Heinrich events has also been hinted at from records of terrestrial ice streams at the southern margin of the LIS (Mooers and Lehr, 1997), but this concept has received little attention.…”

“…Some studies have focussed on potential correlative events from smaller ice streams at the eastern margin of the LIS, such as those draining into Baffin Bay (Andrews et al, 1998; or the continental shelf off Nova Scotia (Piper and Skene, 1998). Further afield, IRD events have also been detected in the Arctic Ocean (Darby et al, 2002;Darby, 2003) and attributed to source areas in the Canadian Arctic Archipelago (Stokes et al, 2005) and Eurasia . Although obtaining precise ages for Arctic…”

Modeling of Polar Ocean Tides at the Last Glacial Maximum: Amplification, Sensitivity, and Climatological Implications

“…These events, during which large volumes of ice were discharged into the North Atlantic from close to the mouth of the present-day Hudson Strait, are associated with rapid climate change. The much smaller Innuitian ice sheet appears to have suffered a similar episodic instability, leading to ice discharge into the Arctic Ocean from the Queen Elizabeth Islands (Darby et al 2002). In this scenario, the largeamplitude tides of the Labrador Sea are implicated in the collapse of the Laurentide ice sheet (Arbic et al 2004b(Arbic et al , 2008, while the megatides around the Queen Elizabeth Islands are implicated in the collapse of the Innuitian ice sheet (Griffiths and Peltier 2008).…”

Changes in terrestrial organic matter input to the Mendeleev Ridge, western Arctic Ocean, during the Late Quaternary

“…Because the only source of this detrital carbonate (mostly dolomite) in the central Arctic Ocean is derived from the Laurentide part of the Canadian Archipelago (Bischof et al, 1996;Darby et al, 2002), this type may have derived by icebergs from the same source.…”

“…IRD source areas have been determined using mineral and chemical compositions (e.g., Stein et al, 1994;Bischof and Darby, 1997;Darby et al, 2002). Organic geochemistry has also been applied in such studies; the amount and quality of bulk OM have been reported for sediment cores from the Amundsen Basin (Schubert and Stein, 1996) and the Siberian continental margins (Stein et al, 2001(Stein et al, , 2004Bouscein et al, 2002).…”