[Parameters: Topic='OCEANS', Term='MARINE SEDIMENTS', Variable_Level_1='STRATIGRAPHIC SEQUENCE']
Wilkes Land Glacial History (WEGA)Entry ID: ASAC_1044
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.
Start Date: 2000-09-30Stop Date: 2001-03-31
Paleo Temporal Coverage
OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY
OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > WATER DEPTH
OCEANS > COASTAL PROCESSES > SEDIMENT TRANSPORT
OCEANS > COASTAL PROCESSES > SEDIMENTATION
OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > CONTINENTAL MARGINS
OCEANS > MARINE SEDIMENTS > SEDIMENT COMPOSITION
OCEANS > MARINE SEDIMENTS > SEDIMENT TRANSPORT
OCEANS > MARINE SEDIMENTS > SEDIMENTATION
OCEANS > MARINE SEDIMENTS > STRATIGRAPHIC SEQUENCE
OCEANS > MARINE SEDIMENTS > TERRIGENOUS SEDIMENTS
OCEANS > MARINE SEDIMENTS > TURBIDITY
OCEANS > OCEAN CIRCULATION > OCEAN CURRENTS
OCEANS > OCEAN CIRCULATION > THERMOHALINE CIRCULATION
OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE
OCEANS > SALINITY/DENSITY > CONDUCTIVITY
PALEOCLIMATE > OCEAN/LAKE RECORDS > MICROFOSSILS
PALEOCLIMATE > OCEAN/LAKE RECORDS > PALEOMAGNETIC DATA
PALEOCLIMATE > OCEAN/LAKE RECORDS > RADIOCARBON
PALEOCLIMATE > OCEAN/LAKE RECORDS > SEDIMENTS
PALEOCLIMATE > OCEAN/LAKE RECORDS > STRATIGRAPHIC SEQUENCE
SOLID EARTH > TECTONICS > EARTHQUAKES > SEISMIC PROFILE
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
Please follow instructions listed in the citation reference provided at the URL below when using these data.
Data Set Progress
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 3 6226 2504
Fax: +61 3 6226 2973
Email: P.Harris at utas.edu.au
Churchill Avenue Antarctic CRC University of Tasmania
City: Sandy Bay
Province or State: Tasmania
Postal Code: 7005
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.
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2000-08-09
Last DIF Revision Date: 2014-01-10