From Australian Oceans Data Network
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Evidence of an exhalative origin for deposits of the Cobar district, New South Wales

Created 21/12/2025

Updated 21/12/2025

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Evidence is presented to show that a strong mineralogical/chemical zoning exists in seven deposits of the Cobar-Nymagee area. Characteristically, the within-deposit zoning, perpendicular to bedding, consists of a siliceous chalcopyrite-pyrrhotite eastern side with diffuse contacts against adjacent siltstone-shale host rocks, and a relatively massive sulphide, banded, pyrite-sphalerite-galena western side with sharp contacts against host rocks. Features such as these are typical of those in exhalative deposits in volcanic terrain and are taken here to indicate a similar origin in this essentially non-volcanic environment. The deposits are contained in distal turbidite facies of the Devonian Cobar Supergroup, deposited in a meridional trough bounded on its eastern flank by a possible penecontemporaneous growth fault separating the trough from an adjacent shelf area on which were deposited shallow-water marine sediments and terrestrial and marine volcanics. This volcanism and the Cobar sedimentary-exhalative deposits may be related through rifting in the area which produced the proposed growth faults and the subsequent Cobar Trough. The deposits, now in 20° discordancy to bedding, are considered to have been transposed into the prominent regional cleavage during post-ore deformation. Using the syn-sedimentary exhalative concept, two mineralised horizons and a possible tight syncline may be recognised in the CSA mine.

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Field Value
Title Evidence of an exhalative origin for deposits of the Cobar district, New South Wales
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/ae0878fd-8b36-455e-a038-87e4ced8427a
Contact Point
Australian Ocean Data Network
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
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        145.25,
        -32.5
      ],
      [
        146.75,
        -32.5
      ],
      [
        146.75,
        -30.75
      ],
      [
        145.25,
        -30.75
      ],
      [
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      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Australian Oceans Data Network

Data Source

This dataset was originally found on Australian Oceans Data Network "Evidence of an exhalative origin for deposits of the Cobar district, New South Wales". Please visit the source to access the original metadata of the dataset:
https://catalogue.aodn.org.au/geonetwork/srv/eng/csw/dataset/evidence-of-an-exhalative-origin-for-deposits-of-the-cobar-district-new-south-wales1