This record outlines models for the tectonic evolution of Australian Proterozoic terranes, and the mineral systems that are likely to have operated in particular regions at particular times.

The rifting history of the magma-poor conjugate margins of Australia (Great Australian Bight) and Antarctica (Terre Adélie) is still a controversial issue. In this paper, we present a model for lithosphere-scale rifting and deformation history from initial rifting to breakup, based on the interpretation of two regional conjugate seismic profiles of the margins, and the construction of a lithosphere-scale, balanced cross section, sequentially restored through time. The model scenario highlights the symmetric pattern of initial stretching resulting to pure shear at lithospheric-scale accompanied by the development of four conjugate detachments and crustal half-graben systems. This system progressively evolves to completely asymmetric shearing along a single south-dipping detachment at the scale of the lithosphere. The detachment accounts for the exhumation of the mantle part of the Australian lithosphere, and the isolation of a crustal klippe separated from the margin by a peridotite ridge. Antarctica plays the role of the upper plate with the formation of an external crustal high separated from the unstretched continental crust by a highly extended zone still active during the Australian exhumation phase. The total elongation amount of the Australian-Antarctic conjugate system reaches ~413km (61%). Elongation was partitioned through time: ~189km and ~224km during symmetric and asymmetric stages, respectively. During symmetric stage, both margins suffered relatively the same elongation accommodated by crustal stretching (~105km (45%) and ~84km (38%) for Australia and Antarctica, respectively). Again, both margins accommodated relatively the same elongation during the asymmetric stage: the Antarctic upper plate records an elongation amount of ~225km (40%) as crustal tectonic stretching, above the inferred low-angle south dipping detachment zone, whereas the Australian lower plate suffered ~206km (61%) of elongation through mantle exhumation.

Describes a suite of LREE-enriched basaltic to felsic magmas from the Maillina Basin, Pilbara Craton. Uses geochemistry and Sm-Nd isotopic data to argue for the operation of subduction (of oceanic crust) processes at c. 3.0 Ga.

The Whundo Group, in the Pilbara Craton of northwestern Australia, is exceptional amongst Mesoarchaean, or older, volcanic sequences in that it preserves geochemical characteristics that are extremely difficult to interpret in any way other than reflecting modern-style subduction processes, most likely at an intra-oceanic arc. The group includes boninites, interlayered tholeiitic and calc-alkaline volcanics, Nb-enriched basalts, adakites, and shows evidence for flux melting of a mantle wedge. The geochemical data are also consistent with geological relationships that infer an exotic terrane with no felsic basement. These data provide clear evidence for modern-style subduction processes at 3.12 Ga.

Lying off the south-west coast of Australia some 2,500 m below sea level is the broad, rectangular Naturaliste Plateau, which forms a relatively flat ledge half way between sea level and the abyssal plain. How the plateau came to be in this position, and whether its origin is continental or oceanic, are two questions relevant to the evolution of the south-east Indian Ocean.

Well-preserved volcanic sequences span the Paleoarchean to Neoarchean evolution of the Pilbara Craton, in northwestern Australia. This region provides the best physical evidence bearing on the stage of Earth's history when modern-style tectonic processes began. Paleoarchean assemblages in the eastern nucleus of the craton (the 3.51-3.24 Ga Pilbara Supergroup) show few features that can reasonably be interpreted as evidence for modern-style subduction processes. Incompatible trace element-enriched felsic volcanic horizons show geochemical evidence for the interaction between mafic magmas and crust, but this evidence, on its own, can equally well be interpreted in terms of either a subduction-enriched mantle source or local and limited assimilation of felsic crust into the voluminous tholeiitic magmas that dominate the Pilbara Supergroup. Viewed in context within the thick autochthonous and consistently upward-younging Pilbara Supergroup, these felsic units are most likely related to the same plume-dominated processes that formed the basalts that dominate the supergroup. It is very unlikely that modern-style plate tectonic processes played any role in the Paleoarchean evolution of the Pilbara Craton, although some form of nonuniformitarian (e.g. flat) subduction process may have operated. In stark contrast, the Mesoarchean units of the West Pilbara Terrane and the late-tectonic basins that cover that boundary between the West and East Pilbara Terranes, show clear evidence for modern-style convergent margin processes. Igneous rocks in this belt, which flanks the old eastern cratonic nuclei, have enriched geochemical signatures that cannot be accounted for by crustal contamination. This region is also characterised by a linear magmatic and structural fabric, by the presence of lithologically and geochronologically exotic belts, and by the presence of a broad belt of isotopically more juvenile crust. The collective strength of these arguments provides compelling evidence that a modern-style oceanic arc fringed the East Pilbara Terrane at 3.12 Ga and accreted to that terrane by 2.97 Ga. These assemblages mark the minimum age for the birth of modern-style plate subduction process.

Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. The North Australian Craton, which stretches from the Kimberley Craton, in the west, to the Mt Isa Inlier, in the east, and from the Pine Creek Orogen, in the north, to the Warumpi Province in the south, began in the late Archaean and continued through much of the Palaeoproterozoic, terminating at about 1635 Ma with accretion of the Warumpi Province during the Leibig Orogeny (Close et al., 2006). The growth of this craton was accompanied by mineral systems that produced world class lode gold (Callie), Zn-Pb-Ag (Mt Isa-type-MIT: Mt Isa, Hilton, HYC and Century; and Broken Hill-type-BHT: Cannington), unconformity U (Jabiluka), and iron oxide-copper-gold (IOCG: Ernest Henry) as well as smaller, but still economic, magmatic-related W-Mo and Sn-Ta deposits, and uneconomic volcanic-hosted massive sulphides (VHMS) and layered mafic intrusion-related Ni-Cu-PGE deposits. Over the past fifteen years workers at Geoscience Australia, the Northern Territory Geological Survey, and the Geological Survey of Western Australia have established temporally constrained geological and tectonic frameworks for the constituent parts of the North Australia Craton, into which, mineral systems can be placed. Although some of the frameworks presented here are well established, others are speculative and are presented to assess potential implications to the evolution of the North Australian Craton. <p>Related product:<a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=64764">Evolution and metallogenesis of the North Australian Craton Conference Abstracts</p>

This slide set on Australian volcanoes comprises - 12 page booklet with background information and descriptions of each image - 15 slides - student question/s for each slide Learn the history of Australia's hot spot volcanoes over 60 million years. Compare and contrast recent Australian volcanoes with those elsewhere and examine 9 Australian volcanoes in detail. Suitable for primary levels Years 5-6 and secondary levels Years 7-10

Legacy product - no abstract available

The lower part of the Pilbara Supergroup records 300 million years of voluminous basaltic magmatism from c. 3.515 to 3.24 Ga. The basalts are divided into two compositionally distinct (high-Ti and low-Ti) but contemporaneous and interbeded types. Compared to the low-Ti basalts, the high-Ti basalts (TiO2>0.8 wt%) have relatively high concentrations of HFSE and REE, are generally more Fe-rich, have very low Al2O3/TiO2 (18.7 - 8.9) and high Gd/Yb ratios (1.12-2.23) - they have affinities with Al-depleted (or Barberton-type) komatiites and komatiitic basalts that formed during high pressure melting in particularly hot mantle plumes. The composition of these basalts, and their source, did not change significantly throughout the 300 m.y. period of basalt eruption. In contrast, low-Ti basalts show distinct secular trends to lower concentrations of incompatible trace elements and lower ratios of La/Sm, La/Gd, La/Yb and Gd/Yb that reflect a source progressively more depleted than NMORB source. Gd/Yb ratios in the younger basalts are as low as 0.67, well below estimates for modern depleted mantle (0.98), and reflect a strongly depleted source. The source for the low-Ti basalts formed from the depleted residue of the plumes that produced the earliest high-Ti basalts. It remained isolated from the convecting asthenosphere throughout the 300 m.y. period of basaltic magmatism, but remelted each time one of several younger plumes (the sources for contemporaneous high-Ti basalts) impinged on the lithospheric mantle. The result was a thick pile of interbedded high- and low-Ti basalt. A complimentary, thick, depleted, and buoyant sub-continental lithospheric mantle (SCLM), developed, in situ from the Low-Ti basalt source, and also by accumulation of the plume source for the high-Ti basalts. These results support models for Palaeoarchaean protocrust formation through extensive mantle plume magmatic events, and models that suggest that the Archaean SCLM formed at the same time as early voluminous mafic magmatism. Basalts in the lower Pilbara Supergroup are typically not highly contaminated by felsic crust. Neither the degree of contamination nor the proportion of contaminated rocks appears to have increased significantly with decreasing age, despite clear evidence that the volume of co-existing felsic material increased significantly over that period. Likewise, there is no evidence for subduction modification of mantle sources until the youngest basalts of the uppermost Pilbara Supergroup erupted at c. 3.0 Ga.