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Project name: Coompana Gravity
Project leader: Philip Heath
Project group: Laszlo Katona
Gary Reed
Program:Far West Discovery Program

Synopsis

Map showing location of Coompana Gravity project

The Coompana Province straddles the South Australian – Western Australian border in the state’s far west, located between the western Gawler Craton to the east, the Musgrave Province to the north and the Madura Province (Western Australia) to the west.

There has been little to no exploration that has directly targeted the bedrock of this region, largely because the depth to basement is poorly constrained and the geological characteristics and prospectivity of the region is poorly known.

The Coompana Gravity Survey has been specifically designed to address critical geological and structural uncertainties that exist in the region the by providing a new, exploration-grade geophysical data set. The area also includes the enigmatic Coompana magnetic feature and margins with previous interpretations suggesting parallels with nickel-copper sulfide mineral geological systems such as those seen in Western Australia (eg the Nova Prospect immediately to the west).

The collection of this detailed new gravity dataset will complement the recent and ongoing data and research in the area including the Coompana Airborne Magnetic and Radiometric survey, the Eucla–Gawler Seismic and Magnetotelluric (MT) transects, the AusLAMP regional MT survey and the Eucla–Gawler biogeochemistry survey. The data will be vital in the interpretation and targeting phase of the Coompana Drilling Project.

Background/Aims

The Coompana Province is completely covered by Neoproterozoic to Cenozoic sediments of the Officer, Denman, Bight and Eucla basins and there are no known records of outcropping basement. Drilling records show that there are no more than 12 existing drill holes that intersect basement in the region, affirming the Coompana Province as a true geological and mineral exploration frontier.

The current gravity coverage in the Coompana area is minimal. Existing stations have been collected over a regular grid at 7 km spacing (in some areas 4 km spacing). This resolution is only suitable for very regional studies and is not suitable to image the bedrock geology to a detail required for exploration activities.

Because of these factors the geology and mineral prospectivity of the region is largely unknown.

The primary objective of this project is to acquire gravity at a resolution suitable to generate exploration interest in the Coompana area. The survey will comprise approximately 14,000 new gravity stations at a nominal 2000, 1000, and 500 metre station spacing over an area of approximately 19,895 square kilometres.

The gravity geophysical technique measures the acceleration due to gravity. Typically an instrument is carried to a specific site, placed on the ground, and a measurement acquired before moving to the next site. For the Coompana Gravity survey, each station will be accessed by helicopter to minimise environmental disturbance.

The data will be made freely available via SARIG, and a MESA Journal article will be written covering the geological highlights uncovered by the survey. The data will also feed into future state grid products, to be released via SARIG.

This project is being undertaken in partnership with Geoscience Australia (a Division of the Commonwealth Department of Innovation and Science) under the National Collaboration Framework promoting State–Federal precompetitive geoscientific collaborative programs.

Key outcome

  • 500 m, 1 km and 2 km spaced gravity sampling throughout the Coompana region. This data will be pivotal in generating exploration interest in the region, as well as acting as an economic boost for service providers in the state.

Schedule for information and product delivery

DeliverableTimeframe
Delivery of final data to the Department of State DevelopmentMarch 2017
Data released through SARIGApril 2017
New state-wide gravity image December 2017
Delivery of final data through SARIG April 2017