Authors / CoAuthors
Hill, P.J.
Abstract
In January 2000, the Australian Geological Survey Organisation (AGSO) completed a major, 25-day seabed swath-mapping and geophysical survey off southeast Australia for the National Oceans Office (NOO) and Environment Australia (EA). The survey, named AUSTREA-l and designated as AGSO Cruise 222, used the 85-m French oceanographic and geoscience research vessel L 'Ata/ante, departing Noumea on 18 December 1999 and ending in Hobart on 11 January 2000. The survey covered 11,000 km and mapped about 120,000 km2 of seabed - an area about 1.5 times the size of Tasmania. The work was done for marine zone planning and management, for assessment of seabed living and non-living (petroleum and mineral) resources, and geological and biological research, as a major step towards implementation of Australia's Oceans Policy and Australia's Marine Science and Technology Plan, and in particular, the development of the Southeast Regional Marine Plan by the National Oceans Office. Data collected included Simrad EM 12D swath-bathymetry and backscatter imagery, 6- channel GI-gun seismic, digital 3.5 kHz sub-bottom profiles, gravity and total field magnetics. Also collected was oceanographic information - XBTs to 1800 m depth and underway ADCP (current), sea surface temperature and salinity measurements. Weather and sea conditions were generally favourable, though stormy conditions with 30-35 knot winds and associated rough seas were encountered at times. Data quality was mostly excellent. The survey mapped the volcanic slopes of Lord Howe Island and Ball's Pyramid to the 12 nautical mile outer limits of a proposed Marine Protected Area, revealing a rugged terrain of volcanic cones, flows and canyons likely to harbour diverse benthic communities. The steep and narrow rifted continental margin off the NSW South Coast was shown to be deeply dissected by canyons and to contain gigantic continental fauit blocks fuld ?syw-ift volcanic seamounts and ridges. The survey completed mapping of the huge Bass Canyon complex off southeast Victoria, revealing detailed morphology of tributary canyons up to 1000 m deep adjacent to the Gippsland oil fields. Important fishing grounds of the Southeast Trawl Fishery were mapped off Tasmania, including volcanic and carbonate pinnacle terrain off St Helens, volcanic seamounts of the Southern Hills, and the heads of canyon systems incised into the sedimented upper slope off west Tasmania. Mapping of the Tasmanian Seamounts Marine Protected Area, south of Hobart, was completed, with thirty additional volcanic seamounts found just east and north of the MP A. The seismic profiles confirmed the existence of potential frontier petroleum basins off the east, southern and west coasts of Tasmania. Parts of the deeply-canyoned upper and mid slope of the Otway Basin were mapped off northwest Tasmania, Victoria and South Australia. The Great Australian Bight Benthic Protected Area of the GAB Marine Park was fully surveyed below the 500 m isobath and was shown to be generally a uniform slope, with the gigantic Nullarbor Canyon crossing its southeastern comer, gouged into deformed Late Cretaceous sediments. A full set of shipboard maps was provided to the National Oceans Office; copies of the digital swath-data are held for NOO at AGSO. All data from the cruise will be jointly managed by AGSO, NOO and EA.
Product Type
document
eCat Id
58026
Contact for the resource
Custodian
Owner
Custodian
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GA PublicationRecord
- ( Theme )
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- geophysics
- ( Theme )
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- continental margins
- ( Theme )
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- marine
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- AU-NSWAU-TASAU-VIC
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
2000-01-01T00:00:00
Creation Date
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Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Record 2000/006
Lineage
Unknown
Parent Information
Extents
[-47.0, -30.0, 128.0, 160.0]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Source data not available.