Geomorphology of the Australian Margin  

Authors / CoAuthors

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

Abstract

For the first time, the distribution of seabed geomorphic features has been systematically mapped over the Australian margin. Each of 21 feature types was identified using a new, 250 m spatial resolution bathymetry model and supporting literature. The total area mapped was >8.9 million km2 and included the seabed surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie and Norfolk Islands. Of this total, the shelf is >1.9 million km2 (21.92%), the slope >4.0 million km2 (44.80%), and the abyssal plain/deep ocean floor >2.8 million km2 (32.20%). The rise covers 97,070 km2 or 1.08% of the margin. A total of 6,702 individual geomorphic features were mapped on the Australian margin. 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 <5%. Reefs, which total 4,172 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 seabed geomorphology indicates that the Australian margin is relatively under-represented in shelf, rise and abyssal plain/deep ocean floor area and over-represented in slope area, a pattern that reflects the mainland being bounded on three sides by passive continent-ocean rifted margins and associated numerous subsided marginal plateaus. Significantly, marginal plateaus on the Australian margin cover 20% of the total world area of marginal plateaus. The Australian margin can be divided into 10 geomorphic regions by quantifying regional differences in diagnostic features that can be used to infer broad-scale seabed habitats. The present study has application for the future management of Australia's ocean resources.

Product Type

nonGeographicDataset

eCat Id

65003

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Keywords

• External PublicationScientific Journal Paper

( Theme )

• bathymetry

( Theme )

• mapping

( Theme )

• geomorphology

( Theme )

• marine

• AU

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2006-01-01T00:00:00

Creation Date

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

Access - restricted

Use - license

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Purpose

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unknown

Topic Category

geoscientificInformation

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Unknown

Parent Information

Extents

[-64.0, -9.0, 92.0, 164.0]

Reference System

Spatial Resolution

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