Ice sheets viewed from the ocean: the contribution of marine science to understanding modern and past ice sheets

Abstract

Over the last two decades, marine science, aided by technological advances in sediment coring, geophysical imaging and remotely operated submersibles, has played a major role in the investigation of contemporary and former ice sheets. Notable advances have been achieved with respect to reconstructing the extent and flow dynamics of the large polar ice sheets and their mid-latitude counterparts during the Quaternary from marine geophysical and geological records of landforms and sediments on glacierinfluenced continental margins. Investigations of the deep-sea ice-rafted debris record have demonstrated that catastrophic collapse of large (10 5 -10 6 km 2 ) ice-sheet drainage basins occurred on millennial and shorter time scales and had a major influence on oceanography. In the last few years, increasing emphasis has been placed on understanding physical processes at the ice-ocean interface, particularly at the grounding line, and on determining how these processes affect ice-sheet stability. This remains a major challenge, however, owing to the logistical constraints imposed by working in ice-infested polar waters and ice-shelf cavities. Furthermore, despite advances in reconstructing the Quaternary history of mid-and high-latitude ice sheets, major unanswered questions remain regarding West Antarctic ice-sheet stability, and the longterm offshore history of the East Antarctic and Greenland ice sheets remains poorly constrained. While these are major research frontiers in glaciology, and ones in which marine science has a pivotal role to play, realizing such future advances will require an integrated collaborative approach between oceanographers, glaciologists, marine geologists and numerical modellers.

Arctic and Antarctic submarine gullies—A comparison of high latitude continental margins

“…The significant differences in gully incision depth and shelf-indentation observed between some Arctic and Antarctic gullies may therefore reflect differences in the timing of initial glaciation and the number of Subbottom data from some high latitude margins (e.g., Storfjorden TMF, northern Barents Sea; Belgica Fan, Bellingshausen Sea, Antarctica) show that submarine gullies incise glacial debris flow deposits, suggesting that erosion of some gullies likely post-dates the last glacial advance to the shelf edge (Vorren et al, 1989;Laberg et al, 2007;Pedrosa et al, 2011;Ó Cofaigh, 2012). As the most recent episodes of gully erosion (since LGM) may obscure previously developed gullies, it is difficult to rule out gully formation over longer timescales without high resolution three-dimensional seismic datasets from glacial margins.…”

Seabed Characterization: Developing Fit for Purpose Methodologies

“…It has only been over the last two decades, however, that the principles could be adequately applied in a marine setting, where geophysical data have become sufficiently high resolution. Also, glacigenic features are often better preserved in a submarine setting as they have not been subject to millennia of subaerial erosion, and thus marine observations are critical for reconstructing the extent and flow dynamics of past glaciations (Ó Cofaigh, 2012). …”

Progress in marine geoconservation in Scotland’s seas: assessment of key interests and their contribution to Marine Protected Area network planning

“…In turn, this is enabling insights into wider Earth system processes and the coupling of ice-sheet dynamics, ocean processes, climate, the rheology of the upper mantle, glacio-isostatic adjustment and relative sea-level change (Milne et al, 2006;Bradley et al, 2011). Such understanding is not only of academic interest but is of critical importance in informing assessments of the future responses of modern marine-based ice sheets to likely 21st century climate warming, sea-level rise and possible changes in ocean circulation (Clark et al, 2012;Ó Cofaigh, 2012). For example, the British-Irish Ice Sheet may be an analogue for the marine-based West Antarctic Ice Sheet, the future stability of which is a key concern in a warmer world (Vaughan and Arthern, 2007;Lenton et al, 2008), and help to provide empirical evidence to test numerical models of dynamic, fastflowing ice sheets (Boulton and Hagdorn, 2006;Hubbard et al, 2009).…”