Geoscience Reference
In-Depth Information
The Gawler Craton in South Australia is one such example of a mineral-
rich geological terrane that extends offshore. The Gawler Craton hosts the
giant Olympic Dam orebody, an important source for copper (and gold and
uranium).
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Although not a massive sulfide deposit
sensu stricto
, there has
been significant land-based exploration in the Gawler Craton for deposits
of its class, so called iron oxide-copper-gold deposits. Off shore exploration
has included drilling of magnetic and gravity features below relatively shal-
low water (
<
5-10 m) in Spencer Gulf but so far without success.
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7. Conclusions
Growing commercial activity for high value seafloor massive sulfides in
neighboring countries such as Papua New Guinea and New Zealand
may lead companies to focus their attention on fossil sulfide deposits in
Australian waters. With pending changes to maritime boundaries, Australia
will have one of the largest maritime jurisdiction in the world, but its exten-
sive seabed is grossly under explored with respect to mineral resources gen-
erally, and metallic sulfides in particular.
An initial analysis of sulfide mineral potential in Australian water indi-
cates a number of possible areas of prospectivity, and include the following:
(1) Volcanogenic copper-lead-zinc-gold-silver mineralization associated
with fossil volcanic arcs and back arcs in eastern Australian waters,
including Norfolk Ridge, Lord Howe Rise and Three Kings Ridge.
(2) Mississippi Valley-type lead-zinc-silver mineralization in the NW Shelf
area.
(3) Ophiolite-hosted copper mineralization associated with the major strike
slip fault in the Macquarie Ridge Complex.
(4) Submerged extensions of prospective land based terranes, for exam-
ple, the iron oxide-copper-gold potential in the Gawler Craton, South
Australia. It is a reasonable assumption that a similar pattern of min-
eral occurrences and more significant deposits would be found offshore,
if exploration were to proceed in that environment.
Prospective terranes for other styles of mineralization also extend off-
shore and offer potential for new mineral discoveries in the future. The areas
highlighted in this contribution would benefit from pre-competitive surveys
utilizing detailed swath bathymetry mapping, and other appropriate search
techniques such as side scan sonar, detailed magnetics and gravity and
“ground truthing” by dredging, grabs and sediment coring.
