Abstract

The Harris Greenstone Belt in the central Gawler Craton of South Australia has potential for Archaean Ni-Cu-PGE sulphide and Archaean-Proterozoic lode-Au mineralising systems. This map is a preliminary interpretation of the Precambrian basement geology based on aeromagnetics, gravity, and diamond drilling. It highlights the extensive distribution of poorly exposed Archaean komatiites and associated rocks (green) that have a strike extent of at least 300 km. The regional pattern of linear komatiitic sequences associated with ovoid granitic plutons and province-wide shear systems, is very similar to the economically important Eastern Goldfields Province in the Yilgarn Craton, Western Australia. The ca. 2520 Ga Lake Harris Komatiite in the central Gawler Craton of South Australia is the first documented komatiite outside the West Australian Craton and the easternmost occurrence of such primitive ultramafic rocks in Australia. The steeply dipping ultramafic sequence consists of komatiite cumulates, high- to low-Mg komatiite, komatiitic and tholeiitic basalt, and pyroxenite cumulates. The komatiitic rocks display a range of quenched and cumulus textures defined by the different habits of olivine and its alteration products. Trace sulphides form very small (0.01-0.2 mm) single-phase disseminated grains and coarser disaggregated grains. Thick ponded lava lake and distal composite sheet flow facies have been identified in the magmatic environment. Systematic whole rock and mineral chemical trends indicate that despite the effects of recrystallisation and re-equilibration during amphibolite-facies metamorphism, the original magmatic geochemical profiles are largely preserved. The whole-rock data for the Lake Harris Komatiite does not show any obvious Ni depletion during fractionation but indicate a strong olivine control in dominantly S-undersaturated environments. The Lake Harris Komatiite has chemical and initial Nd isotope characteristics similar to typical Al-depleted Archean komatiites.
Google map showing geographic bounding box with values North bound -29.0 East bound 138.0 West bound 133.0 South bound -34.0
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Product Type/Sub Type

dataset - PowerPoint

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2002

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

PowerPoint
geochemistry
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-29.0
East bound
138.0
West bound
133.0
South bound
-34.0

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

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

Metadata File Identifier

a05f7892-db4d-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

2008-11-19

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays