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as they were infilled; a hiatus occurred before coal deposition resumed towards the
end of the Permian. Mid-Permian hiatuses occurred in the Galilee, Gloucester, and
northern Perth Basins, and the Roma Shelf, before the onset of paralic and/or nonmarine
deposition. In the case of the northern Perth Basin, only token amounts of
coal were formed. The southern Perth and Collie Basins were unusual in that coal
accumulation continued uninterrupted there throughout most of the Permian. The
small Mount Mulligan, sub-Laura, Blair Athol, and Oaklands Basins began collecting
their coaly sequences with no related precursor sediments. Harrington & others
(1989) describe the eastern Australian basins in greater detail. Both eustatic and
tectonic controls interacted to produce the features of many basin sequences. Arditto
(1987) has interpreted the Illawarra Coal Measures in terms of the response of an
essentially non-marine system to changes in base level.
MINERALS
Metalliferous deposits in the Australian Permian are virtually confined to the Tasman
Fold Belt System of eastern Australia, especially the New England Orogen and
northern Queensland igneous province. Gold, wolfram, molybdenum, bismuth,
copper, lead, zinc, silver, tin, antimony, and arsenic were emplaced by plutonisnn either
in the intrusives themselves, or in the adjacent skarn and hydrothermal zones.
Volcanism has led to gold, silver, molybdenum, and some uranium mineralization.
Many of the Permian reef ores were the source of gold and tin in Cainozoic alluvial
placers. Some Permian placer gold and tin deposits, and syngenetic manganese and
uranium in marine sediments, also occur. The following resume is largely derived from
the reviews by Murray (1986) and Degeling & others (1986), except where otherwise
indicated.
The earliest Permian mineralisation is often difficult to distinguish from that of the Late
Carboniferous, because of poor age constraints on much of the nnetallogenesis, and
apparently continuous magmatic activity in the orogenic zones during that time.
Undoubtedly the most important region for ores of this age is northern Queensland,
inland from Cairns, where numerous small, but high-grade, occurrences have been
worked. These were formed in connection with the large volumes of felsic magma
related to kinematic extension (Oversby, 1987; Mackenzie, 1987b). Granitoid
intrusives carried with them Au, Ag, Cu, Pb, Sn, W, Mo, and Bi, which were deposited
in veins; Cu, Mo, and Ag, emplaced as porphyry-style deposits; and Pb, Cu, Ag, and
W, lodged in contact skarns where lime-rich sediments were intruded. Volcanics and
their associated sediments came to host volcanigenic, bulk-tonnage, low-grade Au, Ag,
Cu, Zn, U and Mo in breccia pipe, vein stockwork, and skarn bodies. Relatively little
contemporaneous mineralisation was taking place in the New England Orogen,
possibly in Queensland because of a plate transform margin setting interpreted by
Murray & others (1987). Minor tin in sheeted veins is associated with the Bundarra
Plutonic Suite in western New England, and the Hillgrove Plutonic Suite bears locally
substantial Au, Ag, As, and Sb. The serpentinites along the Peel Fault hold cumulate
chronnite deposits, but although an age on nephrite has established Early Permian
tectonism, there is evidence that the serpentinite itself (and hence the chromite)
represents the remains of a pre-Early Devonian ocean floor (Blake & Murchey, 1988).
The Gympie Terrane contains numerous Mn occurrences in quartzite, chert, jasper,
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