Gilmore Project GIS - Geoscience In Land management and Ore System Research for Exploration
Dataset Identification:
Resource Abstract:
The GILMORE project is a pilot study designed to test holistic systems approaches to mapping mineral systems and dryland salinity
in areas of complex regolith cover.The project is coordinated by the Australian Geological Survey Organisation, and involves
over 50 scientists from 14 research organisations. Research partners include: Cooperative Research Centres for Advanced Mineral
Exploration Technologies (CRC AMET), Landscape Evolution and Mineral Exploration (CRC LEME), the CRC for Sensor Signal and
Information Processing, and the Australian Geodynamics Cooperative Research Centre (AGCRC) Land and Water Sciences Division
of Bureau of Rural Sciences (BRS)NSW Department of Land & Water Conservation and the NSW Department of Mineral Resources.
Various universities including the Australian National University, University of Canberra, Macquarie University, Monash University,
University of Melbourne, and Curtin University of Technology, and Australian National Seismic Imaging Resource (ANSIR).The
project area lies on the eastern margin of the Murray-Darling Basin in central-west NSW. The project area was chosen for its
overlapping mineral exploration (Au-Cu) and salinity management issues, and the availability of high-resolution geophysical
datasets and drillhole materials and datasets made available by the minerals exploration industry.The project has research
agreements with the minerals exploration industry, and is collaborating with rural land-management groups, and the Grains
Research and Development Corporation.The study area (100 x 150 km), straddles the Gilmore Fault Zone, a major NNW-trending
crustal structure that separates the Wagga-Omeo and the Junee-Narromine Volcanic Belts in the Lachlan Fold Belt. The project
area includes tributaries of the Lachlan and the Murrumbidgee Rivers, considered to be two of the systems most at risk from
rising salinities. This project area was chosen to compare and contrast salt stores and delivery systems in floodplain (in
the Lachlan catchment) and incised undulating hill landscapes (Murrumbidgee catchment). The study area is characteristic of
other undulating hill landscapes on the basin margins, areas within the main and tributary river valleys, and the footslopes
and floodplains of the Murray-Darling Basin itself.Studies of the bedrock geology in the study area reveal a complex architecture.
The Gilmore Fault Zone consist of a series of subparallel, west-dipping thrust faults, that juxtapose, from west to east,
Cambro-Ordovician meta-sediments and granites of the Wagga Metamorphics, and further to the east, a series of fault-bounded
packages comprising volcanics and intrusions, and siliciclastic meta-sediments. Two airborne electromagnetic (AEM) surveys
were flown in smaller areas within the two catchments. Large-scale hydrothermal alteration and structural overprinting, particularly
in the volcanics, has added to the complexity within the bedrock architecture.
Citation
Title Gilmore Project GIS - Geoscience In Land management and Ore System Research for Exploration
AIRBORNE ELECTROMAGNETICS (AEM) SURVEYData Acquisition and ProcessingWorld Geoscience Corporation (WGC), now Fugro Airborne
Surveys, flew the airborne electromagnetic survey under contract from January to March 1999 utilising the TEMPEST system developed
by CRC AMET. The survey was flown at 150m line spacing along east-west lines. The nominal terrain clearance was 120m for the
transmitter. The three component dB/dt towed bird receiver was towed 100 m behind and 5m below the aircraft. The TEMPESTsystem
operated at a 25 Hz base frequency with a square waveform, 10 ms pulse width and average moment of 27,900 Am2. The sample
rate of the receiver was 13 microseconds, giving the system a bandwidth of 25 Hz to 37.5 kHz. Streamed 13 microsecond data
were recorded and later stacked into 0.2s (12 m) samples during processing. The stacked data were deconvolved using the high
altitude reference waveform and the primary field was removed. These deconvolved ground response data were transformed to
an equivalent B-field response for a perfect 100% duty cycle square wave. These data were binned into 15 windows with centres
ranging from 13 microsecond to16.2 ms.AIRBORNE GEOPHYSICAL DATAData have been compiled from 6 separate surveys.Magnetic and
Gamma-ray Spectrometric DataThe total magnetic intensity (TMI) point located data and each of the four channel (TC,K,U,TH)
point located data for each survey were gridded separately at the optimal grid cell size of one fifth of the line spacing.From
the composite TMI grid, the following grids were derived;-TMI reduced to the pole-First vertical derivative of TMI-RTP-Horizontal
gradient of TMIREGOLITHRegolith landform units were compiled at 1:50 000 from interpretation of 1:60000 and 1:80 000 scale
RC9 panchromatic aerial photographs and four weeks fieldwork. Subsidiary data was derived by analysis of drilling materials,
down-hole geophysics, and airborne gamma-ray spectrometrics.
Metadata standard for this record:
ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata
standard version:
1.1
Metadata record identifier:
a05f7892-b617-7506-e044-00144fdd4fa6
URI for dataset described:
> http://www.ga.gov.au/metadata-gateway/metadata/record/34652/
Metadata record format is ISO19139-2 XML (MI_Metadata)