Geomorphology of the Australian Margin and Adjacent Seafloor

Authors / CoAuthors

Heap, A.D. | Harris, P.T.

Abstract

For the first time, the distribution of seafloor geomorphic features has been systematically mapped over much of the Australian margin and adjacent seafloor. Each of 21 feature types was identified using a new, 250 m spatial resolution bathymetry model and supporting literature. The total area mapped was 48.9 million km2 and included the seafloor surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie and Norfolk Islands. Of this total mapped area, the shelf is 41.9 million km2 (21.92%), the slope 44.0 million km2 (44.80%) and the abyssal plain/deep ocean floor 42.8 million km2 (32.20%). The rise covers 97 070 km2 or 1.08% of the mapped area. A total of 6702 individual geomorphic features were mapped. Plateaus have the largest surface area and cover 1.49 million km2 or 16.54%, followed by basins (714 000 km2; 7.98%), and terraces (577 700 km2; 6.44%), with the remaining 14 types each making up 55%. Reefs, which total 4172 individual features (47 900 km2; 0.54%), are the most numerous type of geomorphic feature, principally due to the large number of individual coral reefs of the Great Barrier Reef. The geomorphology of the margin is most complex where marginal plateaus, terraces, trench/troughs and submarine canyons are present. Comparison with global seafloor geomorphology indicates that the Australian margin is relatively under-represented in shelf and rise and over-represented in slope area, a pattern that reflects the mainland being bounded on three sides by rifted continent ocean margins and associated large marginal plateaus. Significantly, marginal plateaus on the Australian margin cover 20% of the total world area of marginal plateaus. The mapped area can be divided into 10 geomorphic regions by quantifying regional differences in diagnostic assemblages of features, and these regions can be used as a starting-point to infer broad-scale seafloor habitat types.

Product Type

nonGeographicDataset

eCat Id

69597

Contact for the resource

Custodian

EGD

Owner

Commonwealth of Australia (Geoscience Australia)

Custodian

Commonwealth of Australia (Geoscience Australia)
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Digital Object Identifier

http://dx.doi.org/10.1080/08120090801888669

Keywords

External PublicationScientific Journal Paper

( Theme )

bathymetry

( Theme )

continental margins

( Theme )

geomorphology

( Theme )

mapping

( Theme )

marine

AU-EEZ

Australian and New Zealand Standard Research Classification (ANZSRC)

Earth Sciences

Published_External

Publication Date

2008-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence

Access - license

Use - license

Status

Purpose

Maintenance Information

unknown

Topic Category

geoscientificInformation

Series Information

Lineage

Unknown

Parent Information

Extents

[-60.9232, -8.472063, 93.4123, 171.8011]

Reference System

Spatial Resolution

Service Information

Associations

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