Citation

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Sullivan, C.J. & Iten, K.W.B., 1952. The geology and mineral resources of the Brock's Creek District, Northern Territory. Bulletin  012. Bureau of Mineral Resources, Geology and Geophysics, Canberra.

Abstract

This Bulletin presents an account of the general geology, stratigraphy, structure, and mineral resources of the Brock's Creek district, Northern Territory. The general geological mapping of the district was carried out by the Aerial, Geological, and Geophysical Survey of Northern Australia in 1939, and a brief account of the results then obtained has been published (A.G.G.S.N.A., 1939). Some further mapping was carried out in 1950. The most important sedimentary rocks of the district are believed to be of Lower Proterozoic age and have been called the Brocks Creek Group (Noakes, 1949). They are dominantly argillaceous in type, but contain sandy formations as well as thin beds of conglomerate and limestone. Numerous sills of amphibolite, which are of igneous origin, are found within the sedimentary sequence. The sediments and interrelated amphibolites probably attain a thickness of 18,000 feet. Unconformably overlying the Brock's Creek Group is a comparatively thin formation of quartzite which is probably late Proterozoic, in age and is known as the Ruldiva Quartzite. Horizontally bedded Lower Cretaceous sandstone and shale up to 200 feet, thick is found capping mesas ill the district. In the north-eastern section of the area mapped is a concordant body of granite (Brock's Creek Granite), roughly circular in shape at the surface, and haying an average diameter of approximately six miles. A smaller area of concordant granite occurs near Mt. Shoobridge in the south-western portion of the area mapped. A discordant cross-cutting granite (Margaret Granite) cuts through the Brock's Creek sediments in the south-eastern portion of the district and exends for many miles to the south. The Buldiva Quartzite is only gently folded and is not intruded by igneous rocks, but the Brocks Creek Group has been subjected to considerable folding and faulting. The fold axes trend north-westerly or northerly, and marked cleavage has been produced parallel to the fold axes. The fine-grained sediments have been converted into schist in many places. Comparatively broad domal and basin-shape1 folds dominate the general structure of the district, but some anticlinal folds have been comparatively tightly compressed---e.g., the Howley Anticline. Within the 300 square miles of country mapped, it was found that deposits of gold and copper occur within, or close to, one formation, which may be repeated from place to place by folding and faulting. The favourable formation is a graphitic slate but is closely associated with a thin band of conglomerate and is normally associated also with sills of amphibolite. A limestone commonly occurs above or below the graphitic slate, but is lenticular in habit. Ore is commonly found in domal and anticlinal structures within these beds, especially near the more crenulated portions of the structure.
Google map showing geographic bounding box with values North bound -13.5 East bound 132.0 West bound 131.5 South bound -14.0
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dataset - GA Publication - Bulletin

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license
Creative Commons Attribution 3.0 Australia Licence

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Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1952

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dataset

Topic Category

geoscientificInformation

Keywords

GA Publication
Bulletin
mineral deposits
geology
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-13.5
East bound
132.0
West bound
131.5
South bound
-14.0

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Unknown

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onLine

DISTRIBUTION Format

pdf

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distributor
Organisation Name
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Canberra
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Postal Code
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Country
Australia
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Metadata File Identifier

a05f7892-9d0f-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 Date Stamp

1996-10-29

METADATA SECURITY CLASSIFICATION

unclassified

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pointOfContact
Organisation Name
Geoscience Australia
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Canberra
Administrative Area
ACT
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2601
Country
Australia
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Downloads
For information on acquiring this product,
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fax:
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1800 800 173 (within Australia);
 
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