Mineral Deposits The Proterozoic rocks of Australia are endowed with substantial mineral resources, containing significant deposits of iron ore, manganese, uranium, gold, copper, lead, z
Trang 1the Palaeozoic Lachlan Orogen Extensive eruption of
continental flood basalts (Kalkarinji large igneous
pro-vince) of the 510-My-old Antrim Plateau Volcanics
and the Table Hill Volcanics in northern and western
Australia may reflect further mantle plume activity
coincident with this collision
Mineral Deposits
The Proterozoic rocks of Australia are endowed with
substantial mineral resources, containing significant
deposits of iron ore, manganese, uranium, gold,
copper, lead, zinc, silver, nickel, and diamond
(Figure 8) (see Mineral Deposits and Their Genesis)
World-class hematite deposits (Mount Whaleback,
Tom Price) have been produced by enrichment of
the banded iron formations of the Hamersley Basin
during the Palaeoproterozoic The highest grade
low-P deposits (62–69% Fe), have been interpreted as the
product of burial metamorphism of original
super-gene enrichment prior to 1840 Ma More recently,
they have been reinterpreted as the product of
hypo-gene processes related to the expulsion of fluids
into the foreland of the Ophthalmian Orogeny
(2200 Ma) Proterozoic iron ore deposits have also
been mined in the Palaeoproterozoic iron formations
of the Hutchison Group in the Gawler Craton, and
from enrichment of ferruginous placer deposits in the
upper Kimberley Group in the Kimberley Basin
(Koo-lan Is(Koo-land) Manganese has been mined from
super-gene deposits (Woodie Woodie) associated with
Palaeoproterozoic karst developed on dolomites in
the eastern Hamersley Basin
‘Unconformity-related’ uranium ( Au platinum
group elements) deposits (Rum Jungle, Alligator
River) are found in Palaeoproterozoic sedimentary
successions overlying predominantly Archaean
base-ment rocks in northern Australia, and may be related
to interaction of highly oxidized, acidic and Ca-rich
meteoric brine with reduced basement fluids Similar
deposits have been found elsewhere in the Australian
Proterozoic, including Kintyre, where
Neoprotero-zoic metasedimentary rocks overlie
Palaeopro-terozoic basement Metasomatic U deposits and the
metamorphic-related Mary Kathleen deposit occur in
Palaeoproterozoic rocks of the Mount Isa Inlier
Gold is found in a number of settings throughout
the Proterozoic, and historic production is related to
generally small lode-gold occurrences and associated
alluvial deposits Major gold (Cu) mines have been
developed at Telfer in the Yeneena Basin, and at
The Granites in the Granites–Tanami Complex
Min-eralization is centred on metasedimentary rocks in
structural domes and is hypogene, related to the
emplacement of granitic pluton(s) near a periodically
reactivated, regional-scale, fluid-focusing structure, often a strike–slip fault ‘Proterozoic Cu–Au deposits’ are found associated with iron oxide in the Tennant Creek Inlier, at Olympic Dam in the northern Gawler Craton, and in the Mount Isa Inlier (Ernest Henry) There is usually a spatial and temporal relationship between this style of deposit and granite intrusion (e.g., Olympic Dam and the 1590-My-old Hiltaba Suite) Cu mineralization at Mount Isa is regarded
as syn-deformational, late metamorphic, and is a separate event from Pb–Zn–Ag mineralization The Mount Isa orebody is a world-class example of strati-form sediment-hosted Pb–Zn–Ag mineralization, pro-duced by oxidized fluids moving through the sediment pile and being deposited either by seafloor exhalative processes or within the sediments A similar orebody
is present at McArthur River The Broken Hill ore-body is generally regarded as a metamorphosed example of stratiform sediment-hosted minerali-zation, although syn-metamorphic, skarn-type pro-cesses may have modified it Volcanic-hosted massive sulphide (VHMS) Pb–Zn mineralization has been found at Koongie Park in the Halls Creek Orogen Nickel mineralization in the Proterozoic, together with platinum group elements, Cu, and V, is generally associated with layered mafic–ultramafic intrusions such as those in the Halls Creek Orogen (Sally Malay) Large, layered intrusions are also present in the Musgrave Complex (Giles Complex–Nebo and Babel deposits), the Albany–Fraser Orogen (Fraser Complex), and the Arunta Inlier
The Argyle diamond mine, which is the world’s largest, is developed on the 1200-My-old AK1 lamproite pipe intruded into the Halls Creek Orogen Proterozoic diamondiferous kimberlites from 815 Ma are present in the Kimberley Basin (see Igneous Rocks: Kimberlite)
See Also Igneous Processes Igneous Rocks: Kimberlite Large Igneous Provinces Mantle Plumes and Hot Spots Metamorphic Rocks: Classification, Nomenclature and Formation Mineral Deposits and Their Genesis Mining Geology: Exploration; Hydrothermal Ores Plate Tectonics Sedimentary Environments: Depositional Systems and Facies Sedimentary Rocks: Mineralogy and Classification; Banded Iron Formations.Tectonics: Mountain Building and Orogeny.Time Scale
Further Reading Australian Geological Survey Organisation (1998) Geology and mineral potential of major Australian mineral pro vinces AGSO Journal of Australian Geology and Geophysics 17(3): 1 260
AUSTRALIA/Proterozoic 221