Citation

Rollet, N., Fellows, M., Struckmeyer, H.I.M. & Bradshaw, B.E., 2001. Seabed Character Mapping in the Great Australian Bight. Record  2001/042. Geoscience Australia, Canberra.

Abstract

This report presents the results of a regional seafloor mapping study carried out during 2000/2001 as part of Geoscience Australia's South and Southwest Regional Project. The aim was to support future Regional Marine Planning in the Great Australian Bight (GAB) by underpinning biological, environmental and economic assessments with basic information on geomorphology and the seabed character. Four major geomorphological features are present on the margin in the South and Southwest (SSW) region: a continental shelf, marine terraces (including the Eyre and Ceduna Terraces in the GAB), a continental slope and a continental rise. The boundaries of these geomorphological features have been delineated and captured in a Geographical Information System (GIS). The GIS also includes the location of sedimentary basins, plateaus, terraces and canyons previously mapped in the region. Seabed character mapping was carried out for the GAB area only. Five echo facies have been defined in the GAB area based on the interpretation of available 3.5kHz echo-sounding records and high-resolution seismic profiles in terms of acoustic facies, and their groundtruthing against seafloor samples. The interpretation of these facies has been digitised and captured into a GIS. The GIS includes key attributes for every echo facies. The acoustic facies distribution on the GAB margin and offshore in the South Australian abyssal plain shows the importance of geological inheritance to the geomorphology and sea-bed character of the region. Facies I, which represents undisturbed, layered sediments is mainly localised on the shelf, the Eyre and Ceduna Terraces, and in the greater part of the abyssal plain. Facies II, which may represent more disturbed sediments, is confined to the Ceduna Terrace and along two elongated E-W trending areas on the abyssal plain near the continent-ocean boundary. Facies III, associated with extreme (IIIA), moderate (IIIC) and low (IIID) topography, underlies scarps, canyons, and depressions on the continental slope and the abyssal plain. The distribution of acoustic facies from the upper slope down to the abyssal plain indicates that the major sedimentary process in the deep water GAB is deposition of pelagic sediments. Reworking of sediments by both bottom currents and gravity flows is probably limited to submarine canyons.
Google map showing geographic bounding box with values North bound -32.0 East bound 135.0 West bound 125.0 South bound -38.0
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Product Type/Sub Type

dataset - GA Publication - Record

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2001

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

GA Publication
Record
marine
continental margins
geophysics
bathymetry
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-32.0
East bound
135.0
West bound
125.0
South bound
-38.0

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a05f7892-b644-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2001-09-27

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays