Boehm, Gualtiero et al. (2009): West Antarctic ice sheet evolution; new insights from a seismic tomographic 3D depth model in the eastern Ross Sea (Antarctica)

Leg/Site/Hole:
DSDP 28
DSDP 28 271
Identifier:
2010-017942
georefid

10.1016/j.margeo.2009.07.016
doi

Creator:
Boehm, Gualtiero
Istituto Nazionale di Oceanografia e Geofisica Sperimentale-OGS, Trieste, Italy
author

Ocakoglu, Neslihan
Istanbul Teknik Universitesi, Turkey
author

Picotti, Stefano
author

De Santis, Laura
author

Identification:
West Antarctic ice sheet evolution; new insights from a seismic tomographic 3D depth model in the eastern Ross Sea (Antarctica)
2009
Marine Geology
Elsevier, Amsterdam, Netherlands
266
1-4
109-128
This work presents the results of the research project WISE (West Antarctic Ice Sheet Evolution) the main aim of which is to provide new insights about WAIS (West Antarctic Ice Sheet) evolution in the Eastern Ross Sea (Antarctica) since the late Miocene times, from morphological and geophysical analysis of glacial sediments. A square grid of 1230 km high-resolution multi-channel seismic reflection data, multi-beam bathymetry data and nine Sound Velocity Profiles (SVP) were collected in January 2006 from the northwestern sector of the Glomar Challenger Basin (Eastern Ross Sea), and tied to Deep Sea Drilling Program site 271. This work provides a detailed seismic stratigraphic analysis of the Miocene-Quaternary Ross Sea Sequences (RSS) 5-8, previously mapped using regional lower-resolution seismic profiles. Eight seismic units are identified on WISE high-resolution seismic profiles. These units and their boundaries in most of the cases match with previously published stratigraphy, although three new horizons have been identified as reflecting lateral and time-transgressive facies changes. We applied travel time reflection tomography to obtain a detailed 3D model of the investigated area, defined by a depth-seismic velocity volume and by the geometry of 5 selected surfaces. The resulting model is used to reconstruct the geomorphological and depositional history of this sector of the outer continental shelf and to infer ice sheet dynamics during Miocene to Quaternary times. A high velocity anomaly observed in units below the Ross Sea Unconformity 2 (RSU2) of Pliocene age (3-3.7 Ma) is interpreted as indicative of glacial sediments over-compacted by large scale grounding ice sheet expansion. The low velocity of the unit above RSU1 (ca. 0.7 Ma), is associated with normally compacted sediments. Contour depth and isopach maps show migration of the sediment depocenter from RSS-6 to RSS-8, indicating a change in the direction of grounding ice advance over the continental shelf. Acoustic facies and seismic velocity changes occurred during deposition of RSS-8, possibly reflecting a major change in the WAIS dynamics in late Pliocene-Quaternary times. Abstract Copyright (2009) Elsevier, B.V.
English
Serial
Coverage:Geographic coordinates:
North:-75.0000
West:-178.0000East: -173.0000
South:-77.0000

Oceanography; Applied geophysics; acoustical methods; Antarctic ice sheet; Antarctica; bathymetry; Cenozoic; continental shelf; Deep Sea Drilling Project; DSDP Site 271; geophysical methods; geophysical profiles; geophysical surveys; glacial extent; glacial geology; glacial sedimentation; glaciomarine sedimentation; high-resolution methods; ice movement; ice sheets; Leg 28; lithofacies; marine sedimentation; marine sediments; Neogene; outer shelf; Quaternary; reflection methods; Ross Sea; sedimentation; sediments; seismic methods; seismic profiles; seismic stratigraphy; Southern Ocean; surveys; Tertiary; three-dimensional models; tomography; West Antarctic ice sheet;

.