Ice shelf grounding zone features of western Prydz Bay, Antarctica sedimentary processes from seismic and sidescan images  

Authors / CoAuthors

O'Brien, P.E. | De Santis, L. | Harris, P.T. | Domack, E. | Quilty, P.G.

Abstract

Several grounding zone wedges were left on the floor and flanks of Prydz Channel in western Prydz Bay by the Lambert Glacier during the last glacial cycle. Seismic profiles indicate that vertical accretion at the glacier bed was the most important depositional process in forming the wedges, rather than progradation by sediment gravity flows. Sidescan sonographs reveal extensive development of flutes on the sea floor inshore from the wedges, indicating deformable bed conditions beneath the ice. The region inshore of the east Prydz Channel wedge features extensive dune fields formed by currents flowing towards the grounding zone. This orientation is consistent with models of circulation beneath ice shelves in which melting at the grounding line generates plumes of fresher water that rise along the base of the ice shelf, entraining sea water into a circulation cell. The Lambert Deep is surrounded by a large composite ridge of glacial sediments. Internal reflectors suggest formation mostly by subglacial accretion. The sea floor in the Lambert Deep lacks dune fields and shows evidence of interspersed subglacial cavities and grounded ice beneath the glacier. The absence of bedforms reflects sea floor topography that would have inhibited the formation of energetic melt water-driven circulation.

Product Type

nonGeographicDataset

eCat Id

61483

Contact for the resource

Digital Object Identifier

http://dx.doi.org/10.1017/S0954102099000115

Keywords

• External PublicationScientific Journal Paper

( Theme )

• Antarctic data

( Theme )

• marine

( Theme )

• seabed

• AQ

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_External

Publication Date

1999-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

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Purpose

Maintenance Information

unknown

Topic Category

geoscientificInformation

Series Information

11(1)

Lineage

Unknown

Parent Information

Extents

[-70.0, -65.0, 68.0, 80.0]

Reference System

Spatial Resolution

Service Information

Associations

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