EP13A-0920
Multichannel Seismic Investigations of Sediment Drifts off West Antarctica and the Antarctic Peninsula: Preliminary Results from Research Cruise JR298
Monday, 14 December 2015
Poster Hall (Moscone South)
Robert D Larter1, Alastair G. C. Graham2, Javier Hernandez-Molina3, James E T Channell4, Claus-Dieter Hillenbrand5, Kelly A Hogan1, Gabriele Uenzelmann-Neben6, Karsten Gohl6, Michele Rebesco7, David A Hodell8 and JR298 Shipboard Party, (1)NERC British Antarctic Survey, Cambridge, United Kingdom, (2)University of Exeter, College of Life and Environmental Sciences, Exeter, United Kingdom, (3)Royal Holloway University of London, Earth Sciences, London, United Kingdom, (4)Univ. Florida, Gainesville, FL, United States, (5)British Antarctic Survey, Cambridge, United Kingdom, (6)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (7)National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy, (8)University of Cambridge, Cambridge, United Kingdom
Abstract:
The West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula Ice Sheet (APIS) have exhibited significant changes over recent decades but there is still great uncertainty about how rapidly and how far they will retreat in a warmer climate. For example, it remains unclear whether or not the marine-based WAIS “collapsed” during the last interglacial period, resulting in a global sea-level rise contribution of more than 3 m. Previous studies, including Ocean Drilling Program (ODP) Leg 178, have shown that sediment drifts on the continental rise west of the Antarctic Peninsula contain a rich high-resolution archive of Antarctic margin paleoceanography and APIS history that extends back to at least the Late Miocene. The potential of existing ODP cores from the drifts is, however, compromised by the fact that composite sections are incomplete and lack of precise chronological control. A new drilling proposal (732-Full2) has been scientifically approved and is with the JOIDES Resolution Facilities Board of the International Ocean Discovery Program for scheduling. The main aims of the proposal are to obtain continuous, high-resolution records from sites on sediment drifts off both the Antarctic Peninsula and West Antarctica (southern Bellingshausen Sea) and to achieve good chronological control on them using a range of techniques. We present preliminary results from a recent site survey investigation cruise on RRS James Clark Ross (JR298) that obtained high-resolution multichannel seismic reflection data over the proposed sites and adjacent working areas. The new data provide a basis for interpretation of (i) sedimentary processes that operated during the development of the drifts, and (ii) links between depositional systems on the continental rise, paleo-ice-sheet dynamics and paleoceanographic processes. Through further analyses of seismic and other geophysical data, in combination with marine sediment cores retrieved from the proposed sites, we aim to provide insight into polar margin sediment delivery, Antarctic ice-sheet history and stability, and Antarctic margin paleoceanography. Subsequently, the proposed drilling campaign will allow a detailed chronology to be established on extended records that will provide a basis for high-resolution interpretations extending back through the Pliocene.
