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and slate, originally deposited on the eo-Permian ocean floor, and later weathered to
form residual replacement concentrations. In Tasmania, small amounts of Au and Sn
were concentrated by water action in basal conglomerate (Banks & others, 1989).
Recent palomagnetic studies in the Flinders Ranges of South Australia have
suggested that uraniferous quartz-hematite breccias at Mount Painter may be Permo-
Carboniferous in age, although a latest Cretaceous age is also possible (Idnurm &
Heinrich, 1989).
The Early to middle Permian saw the beginning of a shift in the locus of the main
metallogenesis to the New England Orogen. In New South Wales, stratiform Cu, Pb,
Zn, and Ag was developed in felsic volcanics at Halls Peak. In Queensland, the
important Cracow gold and silver deposit was formed in an epithermal vein system in
penecontemporaneous andesites. North of Cracow, the andesites contain some
disseminated copper mineralisation. Volcanogenic massive sulphide orebodies occur
at Mt Chalmers (Au and Cu) and Silver Spur (Ag, Pb and Cu), in silicic volcanics and
graphitic slate respectively. Podiform chromite was emplaced with its host serpentinite
along the suture zone bounding the western Curtis Terrane when the latter was
welded to the central Queensland mainland towards the end of the Early Permian.
The serpentinite also accommodates gold-bearing quartz reefs in two localities. The
major Gympie gold field, in the Gympie Terrane, has no obvious source for its gold;
the metal was precipitated preferentially in a favorable redox environment where quartz
reefs cut across marine carbonaceous shales in volcaniclastics. Uranium was
scavanged by the reducing environment of black pyritic marine shale in the lower
Aberfoyle Formation near Rossarden, Tasmania, to form a low grade sedimentary
uranium occurrence (Banks & others, 1989). In the Blair Athol and western Bowen
Basin region, gold was eroded and concentrated in placer lodes at the base of the
Permian fluvial sequence.
The Late Permian metallization is, once again, not always easy to differentiate from that
of the adjoining Period. In the New England Orogen during this interval it is somewhat
similar in style to that of northern Queensland at the start of the Permian, in that a wide
variety of metals and types of metallogenesis are represented, as numerous deposits
in granitic and volcanic rocks. Au, Sn, As, Sb, and minor W collected in veins and
greisen zones in granitoids and nearby country rock; some intrusives, such as the
Barrington Tops Granodiorite at the southern end of New England, acted as a heat
source for mobilising the metals in surrounding sediments into hydrothermal fluids.
The Au and Sb lodes in the region east of Armidale (e.g. the notable Hillgrove deposit)
had such a metamorphic-hydrothermal origin, with the fluid flow being focussed into
major shear zones. Although most individual ore bodies are small, the collective
production from vein and fracture occurrences has been substantial. Many porphyrystyle
Cu- and Mo-bearing granitoids were also emplaced, but all are sub-economic at
present. Subvolcanic plutonism provided Ag, Au, and lesser Cu, Pb, Zn and Sn in
veins and disseminated mineralization in subaerial to shallow marine intermediate-silicic
volcanics in the Drake region (Markham, 1974; Herbert, 1983; Perkins, 1988). Small
intrusions of gabbro in southeastern Queensland differentiated in place to yield
cumulate magnetite in layers, but the Ti content is high.
Non-metallic economic minerals are few in the Australian Permian. Related to igneous
activity is hydrothermal alunite in fractures and small disseminations in the earliest
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