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Wilkes Land Glacial History (WEGA)

Entry ID: ASAC_1044

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Summary

Abstract: A collaborative Italian/Australian marine geoscience research voyage to the George Vth Land sector of the East Antarctic continental margin was carried out between 11th February and 20th March, 2000, on board the of the RV Tangaroa. The cost of the expedition was shared jointly by the Italian and Australian National Antarctic Research Programs. Twenty four scientific personnel from 13 ... institutions participated in the expedition.

The geophysical data collected includes a total of 1827 km of multi-channel seismic data and 562 km of Chirper sonar data. A total of 11 gravity cores, 28 piston cores, 18 surface grabs and 11 short trigger cores were collected on the voyage. Water profile (CTD) measurements and water samples were collected at nine stations and seabed bottom photographs were made at 11 stations.

The expedition discovered and mapped a shelf sediment drift deposit covering about 400 km2 lying in an >800m deep section of the George Vth basin west of the Mertz Glacier. It is a true 'drift' deposit, since these sediments exhibit a patchy distribution, large-scale bedforms, contain foreset bedding and display a depositional architecture indicative of contour-parallel sediment transport. A significant observation is that the drift thins to the north into an acoustically-transparent veneer; this observation implies that the drift is sourced from the outer continental shelf, with sediment being transported landwards, across the shelf and into an 850m deep inner shelf basin. The 'Mertz Drift' is over 35 m thick and core samples demonstrate that it is composed of laminated, anoxic, gelatinous olive green, silicious mud and diatom ooze (SMO). Preliminary shipboard counts of the laminae suggest a thickness of from 4 to 20mm, with a mean of about 7mm. While the lower sediments are laminated, there is a 20 to 50cm thick sandy drape at the surface over the whole of the drift. This suggests that a recent (late Holocene) change in the depositional environment has occurred, possibly related to changes in the extent of the nearby Mertz Glacier tongue, current regime and/or to the persistence of sea ice over the shelf area.

Multi-channel seismic data show the occurrence of foreset beds at the shelf break, interpreted as having been deposited by ice streams that grounded on the outer shelf during glacial maxima. On the shelf, the seismic character of the seafloor exhibits highly reflective, parabolic reflectors suggestive of crystalline basement, cropping out at the seafloor. Northwards of these basement outcrops, the water depth increases to over 1,100 m which is the George Vth Basin. The basin coincides with an abrupt transition in seismic character from acoustic basement in the south to seaward (northeasterly) dipping reflectors. On the continental rise, seismic sections were taken across a contourite drift deposit and submarine canyon system in 2500 to 3500 m water depth. Piston cores were collected along the profile of one drift deposit which gave a preliminary Mid-Pliocene age to truncated strata that crop out on the drift's steeper lee side. These data will provide useful site-survey information in support of a proposal sent to the Ocean Drilling Program under the auspices of the SCAR-ANTOSTRAT project for drilling key sites along the Antarctic margin.

Description: Italian metadata record for the same project

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

	N: -64.0	S: -67.5	E: 146.0	W: 142.0

Min Depth: 100 Max Depth: 3500

Temporal Coverage

Start Date: 2000-09-30

Stop Date: 2001-03-31

Paleo Temporal Coverage

Chrono Unit:

PHANEROZOIC > CENOZOIC

Location Keywords

OCEAN > SOUTHERN OCEAN

GEOGRAPHIC REGION > POLAR

Science Keywords

OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY

OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > WATER DEPTH

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

ELEVATION

GEOSCIENTIFIC INFORMATION

OCEANS

Quality Values provided in temporal coverage are approximate only.

Note by Dave Connell, Scientific Data Coordinator, Australian Antarctic Division, 2008-11-06
Despite repeated attempts, data have not been able to be recovered from the investigator of this project. I suggest looking at the Italian record held at the Antarctic Master Directory (see URL given below) for further information and possible access to data.

Access Constraints Data may be accessible from the Italian Antarctic record for this project. See the URL below for the link to the Italian metadata record at the Antarctic Master Directory.

Use Constraints This data set conforms to the PICCCBY Attribution License
(http://creativecommons.org/licenses/by/3.0/).

Please follow instructions listed in the citation reference provided at the URL below when using these data.

Ancillary Keywords

WEGA

seismic

Cenozoic

Data Set Progress

COMPLETE

Originating Center

AGSO

Data Center

Australian Antarctic Data Centre, Australia

Data Center URL: http://data.aad.gov.au

Data Center Personnel
Name: DATA OFFICER AADC Phone: +61 3 6232 3244 Fax: +61 3 6232 3351 Email: metadata at aad.gov.au Contact Address: Australian Antarctic Division 203 Channel Highway City: Kingston Province or State: Tasmania Postal Code: 7050 Country: Australia

Personnel

PETER TOWNSEND HARRIS

Role: INVESTIGATOR

Role: TECHNICAL CONTACT

Role: DIF AUTHOR

Phone: +61 3 6226 2504

Fax: +61 3 6226 2973

Email: P.Harris at utas.edu.au

Contact Address:

Churchill Avenue

Antarctic CRC University of Tasmania

City: Sandy Bay

Province or State: Tasmania

Postal Code: 7005

Country: Australia

Publications/References

Brancolini, G., Harris, P. T., and party, s. b. (2000). Post-Cruise Report: Joint Italian/Australian Marine Geoscience Expedition Aboard the R.V. Tangaroa to the George Vth Land Region of East Antarctica during February-March, 2000. Australian Geological Survey Organisation Record No. 2000/19.

Creation and Review Dates

DIF Creation Date: 2000-08-09

Last DIF Revision Date: 2008-11-07

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