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Few areas in the world may be a better sentinel for climate change than the Baffin Bay region, where ocean circulation and ice sheet dynamics are tightly linked. For instance, varying inflow of the West Greenland Current entering Baffin Bay from the southeast will play a key role in the stability of the Greenland Ice Sheet and its vast outlet glaciers like Jakobshavn Isbræ. However, internal ice sheet dynamics are also a major factor in ice sheet stability. The dramatic and accelerating loss of the Greenland ice illustrates the urgent need to understand both external and internal processes that steer the mass balance of a major ice sheet such as that on Greenland, but also of both former and extant ice on the Canadian side of Baffin Bay.

Baffin Bay, surrounded by the most heavily glaciated landscapes in the Northern Hemisphere, is a major recipient of sediment eroded by large Quaternary ice sheets (e.g., Laurentide, Innuitian, and Greenland ice sheets). Thus, sediment archives extracted from Baffin Bay record the history and dynamics of ice sheets under varying climatic forcings and boundary conditions. Consequently, much research has been done in the marginal areas of Baffin Bay, in the direct vicinity of major glacial outlets. Building on previous work on long cores collected during the 1980s and early 1990s, the retrieval of several long, deep-sea cores during two recent expeditions to central Baffin Bay (CCGS Hudson HU2008-029 in 2008, RSS James Clark Ross JR175 in 2009) has fostered further state-of-the-art research of the Pleistocene-to-Holocene glacial history of Baffin Bay. The themed collection of four papers in this issue of the Journal of Quaternary Science presents important, new records of ice sheet change from Baffin Bay sediments that make use of sedimentary fingerprints to better understand ice sheet dynamics against the background of environmental changes.

By applying the technique of sediment-source differentiation for the last 115,000 years in central Baffin Bay, Simon et al. (2014) reveal that the Laurentide and Innuitian ice sheets responded to high-frequency climate fluctuations such as the Dansgaard-Oeschger events. Conversely, ice margin dynamics of the Greenland Ice Sheet were more strongly controlled by large-scale climatic and oceanographic variability such as warm water advection intensity. Andrews et al. (2014) use a similar approach to focus on the depositional activity of the ice sheets surrounding Baffin Bay during the last glacial (marine isotope stage 3 and 2). They illustrate how a dominantly West Greenland-sourced sedimentary record is punctuated by prominent depositional events of northern-sourced detrital carbonate. Despite difficulties with radiocarbon age models, Andrews et al. (2014) reveal that these so-called Baffin Bay Detrital Carbonate (BBDC) events are not coeval with the calcite-dominated Heinrich Events known from the Labrador. They conclude that there were differing causal mechanisms for these prominent depositional events.

On more recent timescales, Jennings et al. (2014) and St-Onge and St-Onge (2014) focus on the record of deglaciation and subsequent changes in Baffin Bay during the Holocene. Jennings et al. (2014) use multiple proxies to examine the western Greenland shelf during ice-margin retreat into DiskoBugt during the last deglaciation. They illustrate the interplay between climate conditions and ice sheet meltwater during deglaciation, and document the ensuing development of sea surface conditions during the Holocene. Finally, St-Onge and St-Onge reconstruct the Holocene paleoenvironment of northern and eastern Baffin Bay by means of the physical and magnetic properties of sediments. Thus, they validate a valuable alternative for traditional reconstructions of paleoenvironmental variability based on microfossils, which are often hard to come by in these harsh arctic settings.

References

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  2. References
  • Andrews JT, Gibb OT, Jennings AE, Simon Q. 2014. Variations in the provenance of sediment from ice sheets surrounding Baffin Bay during MIS 2 and 3 and export to the Labrador Shelf Sea: site HU2008029-0008 Davis Strait. Journal of Quaternary Science 29: 313.
  • Jennings AE, Walton ME, Ó Cofaigh C, Kilfeather A, Andrews JT, Ortiz JD, de Vernal A, Dowdeswell JA. 2014. Paleoenvironments during Younger Dryas-Early Holocene retreat of the Greenland Ice Sheet from outer Disko Trough, central west Greenland. Journal of Quaternary Science 29: 2740.
  • Simon Q, Hillaire-Marcel C, St-Onge G, Andrews JT. 2014. North-eastern Laurentide, western Greenland and southern Innuitian ice stream dynamics during the last glacial cycle. Journal of Quaternary Science 29: 1426.
  • St-Onge M-P, St-Onge G. 2014. Environmental changes in Baffin Bay during the Holocene based on the physical and magnetic properties of sediment cores. Journal of Quaternary Science 29: 4156.