Abstract

Deep seismic refraction and vertical reflection recordings have been made in the southern McArthur Basin, over the Bauhinia Shelf and Batten Trough between Daly Waters and the H .Y.C. mineral deposit, and over the Wearyan Shelf between Borroloola and Westmoreland. In the Batten Trough, McArthur Group rocks have a velocity of 5.81 km/s; no velocity contrast was detected between them and basement. Over the Bauhinia Shelf, 100--200 m of Cainozoic, Mesozoic, and perhaps Cambrian sediments, overlie ?Roper Group sediments (P-wave velocity, V = 4.6 km/s). Below these are probable Tawallah Group rocks (V = 5.8-5.9 km/s). Magnetotelluric measurements define a resistivity contrast, possibly basement, at 6-9 km depth. On the Wearyan Shelf at Borroloola, 370 m of Roper Group (V = 3.58 km/s) overlies 2.9 km of Tawallah Group (V = 5.55 km/s). At Robinson River, 650 m of Cainozoic, thin McArthur Group, and, perhaps, upper units of Tawallah Group (V = 4.81 km/s) were detected. Tawallah Group rocks (V = 5.44 km/s) crop out northwest of Robinson River and are about 2.8 km thick. Basement velocity is 6.04 km/s. Between Robinson River and Westmoreland, basement is 3.5-2.7 km deep. At Westmoreland the McArthur Basin sequence thins against the Murphy Ridge . A layer 260 m thick (V = 3.50 km/s) lies on top of a 2.4 km thick layer (V = 5.44 km/s), and the basement velocity of 5.99 km/s increases to 6.06 km/s towards Robinson River. At mid-crustal depths velocities are 5.9--6.9 km/s , and in the lower crust, to depths of 43 km in the west and 40 km in the east, 6.8-7.5 km/s. Below this, a velocity gradient is interpreted until upper mantle velocities are reached at 43-53 km depth in the west (V = 7.5-8.4 km/s) and 44 km in the east (V = 7.9 km/s). Generally, the crustal structure of the North Australian Craton is characterised by high lower-crustal velocities, broad velocity gradients, and thick crust, which probably evolved from an Archaean continental crust during Proterozoic tectonism.
Google map showing geographic bounding box with values North bound -16.0 East bound 136.5 West bound 135.0 South bound -16.5
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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)

1983-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

81131 Product http://www.ga.gov.au/metadata-gateway/metadata/record/81131/

Keywords

GA Publication
Journal
NT
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-16.0
East bound
136.5
West bound
135.0
South bound
-16.5

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

fae9173a-7048-71e4-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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