Abstract

Three zones of retrograded crystalline basement rocks have been delineated in central Australia. One, along the southwestern margin of the Amadeus Basin, was deformed about 600 m.y. ago during the Petermann Ranges Orogeny. Two one north of the Amadeus Basin, the other north of the Ngalia Basin were deformed during the Carboniferous Alice Springs Orogeny. Each retrograded zone is highly deformed and is flanked on one side by folded and thrust sedimentary rocks and on the other by granulite and amphibolite facies rocks. The high-grade rocks appear to have resulted from several metamorphic episodes in the Precambrian. A major gravity gradient is associated with each retrograded zone; the Bouguer anomaly highs generally occur over the areas of high-grade metamorphic rocks, and the lows over the sedimentary basins and retrograded rocks. In general, the deformed and retrograded zones are moderately to gently dipping. The gravity gradients are so wide and steep that to explain them the deformed zones must pass through the crust into the mantle beneath. The crust and mantle above each deformed zone have been upthrust, bringing granulite facies rocks to the surface and producing Bouguer gravity anomaly highs over the uplifted lower crust and mantle. The deformed zones are similar to the subduction zones that may develop on the margins of continents, but there is no evidence of continental collision in central Australia when they were formed, and they are regarded rather as possible examples of intracontinental plate reactions. They may have extended right across the continent or may terminate against strike-slip (transform) faults. A possible site for such a transform fault in Western Australia is discussed, but its existence is speculative.
Google map showing geographic bounding box with values North bound -26.0 East bound 135.0 West bound 129.0 South bound -28.0
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Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1973-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

109 Product http://www.ga.gov.au/metadata-gateway/metadata/record/109/

Keywords

GA Publication
Bulletin
structural geology
AU-SA
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-26.0
East bound
135.0
West bound
129.0
South bound
-28.0

Lineage

Unknown

Digital Transfer Options

onLine

Distributor

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

Source Description

Source data not available.

Metadata File Identifier

a05f7892-7fbb-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 SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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