Abstract

Pisolitic bauxite containing between 40 and 50 per cent available alumina was discovered on islands off the north-east coast of Arnhem Land in 1949, and after preliminary reconnaissance in 1951 a thorough exploration of the deposits on Marchinbar Island, Wessel group was undertaken by the Australian Aluminium Production Commission. The island is composed of a gently titled alternating sequence of sandstone, siltstone and shale of upper Proterozoic age bearing remnants of a lateritized surface which includes the bauxite occurrences. Bauxite has developed by lateritization of a sericite-quartz siltstone containing rather more than 50 per cent sericite. The rock contains 65 per cent total silica, 19 per cent alumina and 6 per cent potash. Economic bauxite is mainly confined to the Pisolitic zone which has a maximum depth of 16.5 feet and rests upon red or red and black tubular and massive laterite. Over limited areas high alumina values persist downwards into the red tubular zone for a few feet. The deposits were proved by sampling pits sunk at intersections of rectangular grids spaced at 400 feet by 200 feet, except for one deposit (Fox), which was tested on a wider scale. Proved reserves are given in the following table, but the figures for Fox deposits are of a lower order of accuracy and should be regarded as indicated reserves. [See record for full details]. The total is equivalent to 4,500,000 tons of available alumina or 2,380,000 tons of aluminium metal.
Google map showing geographic bounding box with values North bound -10.5 East bound 137.0 West bound 135.5 South bound -12.5
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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)

1953-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

9258 Product http://www.ga.gov.au/metadata-gateway/metadata/record/9258/

Keywords

GA Publication
Record
mineral deposits
geology
resource assessment
AU-NT
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-10.5
East bound
137.0
West bound
135.5
South bound
-12.5

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

Metadata File Identifier

a05f7892-8095-7506-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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