Authors / CoAuthors
Wellman, P.
Abstract
In eastern Australia free-air anomalies and altitudes averaged over 1° x 1° areas show a positive correlation of +0.059 ± .004 mGal. m^-1. lsostatic compensation of topography and crustal masses is thought to be mainly at the base of the crust, but partly deeper in the mantle, and to be almost complete for 1° x 1° areas. In central and western Australia free-air anomalies and altitudes have a zero or slightly negative correlation with a larger scatter; isostatic compensation is thought to be complete only for 3° x 3° areas and to be predominantly at the base of the crust. The deeper compensation in eastern Australia is thought to be related in some way to the youth of the crust and the presence of a low velocity zone at about 130 km. Elsewhere in the world Phanerozoic areas have a positive free-air anomaly altitude correlation, and Precambrian areas a negative correlation; so the different modes of isostatic compensation found in Australia may apply to crust of similar age elsewhere in the world. In Australia the residual 1° x 1° area anomalies found by removing altitude, long wavelength and sedimentary effects generally have an amplitude of 30 mGal and a wavelength of 6°; they are thought to be due to isostatically compensated variations in crustal density. Using these anomalies, variations in crustal thickness are predicted.
Product Type
document
eCat Id
80895
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GA PublicationJournal
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- AUS
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1976-01-01T00:00:00
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unknown
Topic Category
geoscientificInformation
Series Information
BMR Journal of Australian Geology and Geophysics 1:4:297-302
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Unknown
Parent Information
Extents
[-44.0, -9.0, 110.0, 156.0]
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