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Southern Australia, is host to a ca. 1590 Ma Silicic Large Igneous Province (SLIP) that produced approximately 100,000 km3 of felsic and mafic magmas within a 20 myr timeframe. Although a minor component, the mafic magmas within the SLIP present an opportunity to investigate the composition of the mantle sources involved in SLIP formation. The mafic rocks are generally characterised by enrichment in high field strength elements (HFSE) and light rare earth element (LREE), negative Nb-Ta-Ti anomalies, and variable Nd isotopic compositions. Enriched geochemical signatures and lack of correlation with crustal proxy elements in the most primitive magmas (high Mg, Cr, Ni and ε Nd(1590 Ma)) suggest crustal contamination is not significant in the studied samples and the enrichment is a primary source region characteristic. Th/Nb ratios for the suite are mostly >0.2 and the vast majority of ε Nd(t) values are in the range 0 to −5. In the first instance this means that a large proportion of the mafic magma added to the crust during the SLIP event is effectively isotopically indistinguishable from that considered consistent with Paleoproterozoic reworking of Neoarchean crust. Therefore, continental growth occurring during this event would not be detected by methods that are solely reliant on isotopic datasets (e.g. detrital zircons or bulk sediment compositions). The mantle source for the magma is interpreted to be dominantly sub-continental lithospheric mantle (SCLM) with varying magma compositions interpreted to represent a heterogeneous SCLM. Enrichment of the SCLM is considered to be related to metasomatism during earlier subduction events with the isotopic composition of the magmas suggesting it may have been as early as the Neoarchean. • Geochemical and Nd isotopic compositions of mafic rocks related to a c. 1590 Ma SLIP. • Enriched geochemical and isotopic signatures are primary source region features. • Mantle sources include an enriched SCLM and an E-MORB-like mantle source component. • Enrichment of the SCLM via ancient subduction-related metasomatism. [ABSTRACT FROM AUTHOR]

• We contribute 38 new U–Pb ages to the data-poor north-eastern Albany–Fraser Orogen; • Low sample volumes are used to meaningfully investigate concealed basement geology and the location of major Archean–Paleoproterozoic terrane boundaries; • A new and previously unrecognised felsic igneous suite is defined—the Moonyoora Suite (ca. 2030–2010 Ma); • Zircon U–Pb magmatic ages and Lu-Hf analyses indicate that the inception of Biranup Zone extension and magmatism on the southern margin of the Yilgarn Craton began ca. 200 Myr earlier than previously documented; • Emplacement of the Moonyoora Suite occurred at the start of a widespread extensional regime across the West Australian Craton, and a period of increased mafic magmatism globally. Uranium–lead zircon geochronology, zircon lutetium–hafnium isotope analyses and whole-rock geochemistry are used to investigate concealed basement geology and the location of Archean–Paleoproterozoic terrane boundaries in the northeastern Albany–Fraser Orogen (AFO). We identify a new major component of the AFO, and the first compelling evidence for ca. 2030–2010 Ma A-type felsic magmatism in western Australia. Prior to this study, the oldest rocks in the AFO that formed by extension and reworking of the southern Yilgarn Craton margin had protolith emplacement ages of ca. 1810–1800 Ma; our results extend this record by ca. 200 Myr and provide new insights into the crustal and tectonic evolution of the AFO. This phase of magmatism marks the start of a long-lived and widespread Paleoproterozoic extensional regime that prevailed across the West Australian Craton (WAC) for ∼ 400 Myr. Extension in the WAC was coeval with localised magmatism, volcanism and volcano-sedimentary basin formation in the North and South Australian cratons. Globally, our findings also correlate with the onset of prolonged extension and the generation of a vast tract of oceanic crust around the periphery of Nuna. We posit a petrogenetic link between ca. 2030–2010 Ma felsic rocks in the AFO and age–isotope-equivalent ultramafic–mafic rocks in the eastern Yilgarn Craton that are located along-strike and are interpreted to reflect a possible far-field and late-stage magmatic expression of the ca. 2060–2055 Ma Bushveld superplume. [ABSTRACT FROM AUTHOR]

Abstract: Isotopic, geochemical and U–Pb zircon geochronological characteristics of the Nawa Domain in the South Australian Craton, Australia, have been determined to place constraints upon Palaeoproterozoic reconstruction models. U–Pb detrital zircon analysis of the Nawa Domain metasedimentary rocks indicates deposition between ca. 1740 and 1720Ma. Sedimentary rocks are shown to be enriched in REE and sourced from evolved crust (ɛ Nd(1.6Ga)=−7.0 to −4.3). The combination of geochemical, Nd-isotope and U–Pb detrital zircon age data indicate the dominant source for the studied metasedimentary rocks is likely to be the Arunta region of the North Australian Craton. This indicates the Nawa Domain crustal segment was proximal to the North Australian Craton during the period ca. 1740–1720Ma. Provenance correlations drawn between the Nawa Domain metasedimentary rocks, lower part of the Willyama Supergroup in the Curnamona (Broken Hill) region and Maronan Supergroup in the Mount Isa region suggest contiguity of these crustal terranes during the late Palaeoproterozoic. These spatial and temporal constraints negate some reconstructions of Palaeoproterozoic Australia suggested for this period, and indicate further refinement of other models is needed. Further, the intra-continental nature and Australian sourced detritus of the lower sections of these basins limits their use as piercing points between eastern Australia and possible neighbouring continents in the Palaeo- and Mesoproterozoic. [Copyright &y& Elsevier]

• Two new igneous suites are defined, the Kayilirra Suite (ca. 1500 Ma) and the Kalyukuyarra Suite (ca. 1185–1165 Ma). • Zircon Lu-Hf isotope data and Sm-Nd whole rock data indicate a mixture of crustal reworking and crustal growth during the Mesoproterozoic. • Lu-Hf isotope arrays display positive "steps" and dilution of older isotope signatures with the addition of mantle-derived magmas to the crust. • The Rudall Province, Western Australia, shares a Mesoproterozoic evolution with the west Musgrave Province suggesting they were both part of the West Australian Craton. The Rudall Province in Western Australia is a key crustal component in the amalgamation of the Rodinia supercontinent. New field observations, U–Pb zircon geochronology and geochemistry identify three previously unrecognised Mesoproterozoic magmatic events in the eastern Rudall Province. The Kayilirra Suite formed at ca. 1500 Ma and is a magnesian, calc-alkalic to alkali-calcic and weakly peraluminous suite with a limited SiO 2 range of 69–70 wt%. The suite is interpreted to have formed in either a post-tectonic or rift-related setting. The Kalyukuyarra Suite formed at ca. 1185–1165 Ma and was synchronous with a peak in magmatic activity in the along-strike Musgrave Province. The suite is magnesian to ferroan, alkali-calcic and calc-alkalic, high K and peraluminous. Abundant inherited zircon grains indicate a dominantly crustal origin for the suite with only minor interpreted mantle input. Newly identified mafic and felsic magmatism was associated with the ca. 1380–1275 Ma Parnngurr Orogeny and further establishes correlations with the Mount West Orogeny in the Musgrave Province and "Stage 1" of the Albany-Fraser Orogeny. The new data support the progressive, final amalgamation of the Australian-Antarctic crustal fragments during the period ca. 1380–1250 Ma through consumption of oceanic crust below the over-riding West Australian Craton. [ABSTRACT FROM AUTHOR]

Two-dimensional, lithospheric-scale magnetotelluric imaging in the central Australian Proterozoic has constrained the large-scale architecture of terrane assembly during Paleoproterozoic accretion and collision. The comparatively conductive North Australian craton, consisting of rocks between ∼2500 and 1730 Ma in age, has been imaged to extend for 150 km under the 1690-1620 Ma Warumpi Province, which forms part of a large, comparatively juvenile terrane in central-southern Australia. Collision between the North Australia craton and Warumpi Province occurred ca. 1640 Ma. The boundary between these domains is modeled to be subvertical at crustal scale, but dips south at ∼45° in the mantle to depths of 150 km. We interpret this geometry to reflect lithospheric-scale underthrusting of the North Australian craton beneath the Warumpi Province, and suggest that it provides a first-order constraint on subduction polarity during collision ca. 1640 Ma. In contrast, most contemporary models for the evolution of Paleoproterozoic Australia propose that the North Australian craton was located on the overriding plate of a long-lived (ca. 1800-1550 Ma) north-directed subduction system. The polarity of these models is not consistent with the lithosphericscale geophysical architecture. [ABSTRACT FROM AUTHOR]