Australian Proterozoic orogenic belts are typically characterised by high-temperature, low-pressure, long-lived metamorphism and near-isobaric cooling. However, this is not the case for the Nimbuwah Domain, the easternmost part of the Pine Creek Orogen and part of the oldest core of the North Australian Craton. Here we present new field relationships, geochemical, metamorphic, SHRIMP zircon and monazite U-Pb age, and zircon Lu-Hf and whole-rock Sm-Nd isotopic data for the Nimbuwah Complex and metasedimentary rocks of the Cahill Formation that they intruded in the Nimbuwah Domain. On the basis of these data we propose a new tectonic model for the Paleoproterozoic evolution of the Pine Creek Orogen. SHRIMP zircon U-Pb age data show that granitic to dioritic plutons of the Nimbuwah Complex were emplaced from 1871-1857 Ma at - 9.2 kbar and 650-C into thickened crust during D2-D3 west-directed thrusting and folding. This is termed the Nimbuwah Event. The Nimbuwah Complex was formed by partial melting of Neoarchean granites in the mid to lower crust and mixing with a juvenile magma component. The overthickened crust underwent extensional uplift to <5 kbar by 1855 Ma, constrained by monazite growth during garnet breakdown associated with syn- to late-D2 decompression. We propose that crustal thickening and magmatism occurred in response to collision of Neoarchean to Paleoproterozoic basement of the Pine Creek Orogen (the over-riding plate) with an unknown collider, now concealed beneath younger cover to the east. Exhumation of at least a 15 km crustal thickness within only a few million years indicates a short period of collisional orogenesis, consistent with the observed metamorphic evidence for a low thermal gradient during crustal thickening. Tectonic uplift and erosion of the Nimbuwah Complex fed the retro-arc Cosmo Supergroup and possibly other Paleoproterozoic successions of the North Australian Craton that are dominated by c. 1870 Ma detritus. The low thermal gradient in overthickened crust, which is unusual for Proterozoic Australia, might be a consequence of collision between relatively cool, rigid Archean blocks.

The fundamental geological framework of the concealed Paleoproterozoic East Tennant area of northern Australia is very poorly understood, despite its relatively thin veneer of Phanerozoic cover and its position along strike from significant Au–Cu–Bi mineralisation of the Tennant Creek mining district within the outcropping Warramunga Province. We present 18 new U–Pb dates, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), constraining the geological evolution of predominantly Paleoproterozoic metasedimentary and igneous rocks intersected by 10 stratigraphic holes drilled in the East Tennant area. The oldest rocks identified in the East Tennant area are two metasedimentary units with maximum depositional ages of ca. 1970 Ma and ca. 1895 Ma respectively, plus ca. 1870 Ma metagranitic gneiss. These units, which are unknown in the nearby Murphy Province and outcropping Warramunga Province, underlie widespread metasedimentary rocks of the Alroy Formation, which yield maximum depositional ages of 1873–1864 Ma. While parts of this unit appear to be correlative with the ca. 1860 Ma Warramunga Formation of the Warramunga Province, our data suggest that the bulk of the Alroy Formation in the East Tennant area is slightly older, reflecting widespread sedimentation at ca. 1870 Ma. Throughout the East Tennant area, the Alroy Formation was intruded by voluminous 1854–1845 Ma granites, contemporaneous with similar felsic magmatism in the outcropping Warramunga Province (Tennant Creek Supersuite) and Murphy Province (Nicholson Granite Complex). In contrast with the outcropping Warramunga Province, supracrustal rocks equivalent to the 1845–1810 Ma Ooradidgee Group are rare in the East Tennant area. Detrital zircon data from younger sedimentary successions corroborate seismic evidence that at least some of the thick sedimentary sequences intersected along the southern margin of the recently defined Brunette Downs rift corridor are possible age equivalents of the ca. 1670–1600 Ma Isa Superbasin. Our new results strengthen ca. 1870–1860 Ma stratigraphic and ca. 1850 Ma tectono-magmatic affinities between the East Tennant area, the Murphy Province, and the mineralised Warramunga Province around Tennant Creek, with important implications for mineral prospectivity of the East Tennant area. Appeared in Precambrian Research Volume 383, December 2022.

To test existing geological interpretations and the regional stratigraphic relationships of the Carrara Sub-basin with adjacent resource-rich provinces, the deep stratigraphic drill hole NDI Carrara 1 was located on the western flanks of the Carrara Sub-basin, on the seismic line 17GA-SN1. The recovery of high quality near-continuous core from the Carrara Sub-basin, in concert with the spectrum of baseline analytical work being conducted by Geoscience Australia through the EFTF program, as well as other work by government and university researchers is greatly improving our understanding of this new basin. While recently published geochemistry baseline datasets have provided valuable insight into the Carrara Sub-basin, the age of the sedimentary rocks intersected by NDI Carrara 1 and their chronostratigraphic relationships with adjacent resource rich regions has remained an outstanding question. In this contribution, we present new sensitive high-resolution ion microprobe (SHRIMP) geochronology results from NDI Carrara 1 and establish regional stratigraphic correlations to better understand the energy and base-metal resource potential of this exciting frontier basin in northern Australia.

This Record presents new Sensitive High Resolution Ion Micro Probe (SHRIMP) U–Pb geochronological results for five drill core samples from the Rover mineral field, an area of prospective Palaeoproterozoic rocks southwest of Tennant Creek that is entirely concealed below younger sedimentary cover rocks. The work is part of an ongoing collaborative effort between Geoscience Australia (GA) and the Northern Territory Geological Survey (NTGS) that aims to develop better understanding of the geological evolution and mineral potential of this region. It is being undertaken as part of the Northern Territory Government’s Resourcing the Territory (RTT) initiative and the Federal Government’s Exploring for the Future (EFTF) program and was carried out under the auspices of the National Collaborative Framework (NCF) between GA and NTGS. The rocks studied were sampled from drill cores acquired under the Northern Territory Government’s Geophysics and Drilling Collaborations program; the drillholes sampled comprise RVDD0002 (Wetherley and Elliston 2019), MXCURD002 (Burke 2015) and R27ARD18 (Anderson 2010). <b>Bibliographic Reference:</b> Cross A, Huston D and Farias P, 2021. Summary of results. Joint NTGS–GA geochronology project: Rover mineral field, Warramunga Province, January–June 2020. <i>Northern Territory Geological Survey</i>, <b>Record 2021-003</b>.

This record presents new Sensitive High Resolution Ion MicroProbe (SHRIMP) U– Pb zircon results for eighteen samples from the Cairns, Cape York and Georgetown regions in Queensland. Samples from the Cairns region comprise one granite and one microgranite. Eight samples from the Cape York region and three from the Georgetown region comprise Paleozoic igneous rocks, all but one of which are part of the Carboniferous to Permian Kennedy Igneous Association. Of particular interest are the results for two rhyolitic intrusions from the Coen Inlier that are host to gold mineralisation and gave ages of approximately 280 Ma. These results are supported by similar ages reported by Kositcin et al. (2016), also from felsic dykes spatially associated with gold mineralisation. Together, they suggest a widespread, early-Permian gold (Kungurian) event in this region. The results for two felsic dykes spatially associated with gold mineralisation much farther to the south in the Georgetown region, also gave similar early-Permian ages. The geochronology of five metamorphic rocks from the Cape York region, which were analysed in support of the Coen–Cape Weymouth geology mapping project has resulted in all samples being reassigned to other formations. The work contained in this report was carried out under the auspices of the National Collaborative Framework (NCF) between Geoscience Australia and the Geological Survey of Queensland. The data and age interpretations are also available in Geoscience Australia’s Geochronology Delivery database (http://www.ga.gov.au/geochron-sapub-web/). <b>Bibliographic Reference: </b>CROSS, A.J., DHNARAM, C., BULTITUDE, R.J., BROWN, D.D., PURDY, D.J. & VON GNIELINSKI, F.E., 2019. Summary of results. Joint GSQ–GA geochronology project: Cairns, Cape York and Georgetown regions, 2015–2016. <i>Queensland Geological Record</i> <b>2019/01</b>.

This Record presents new zircon U–Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP) for six samples of volcanic and intrusive rocks from the Cobar Basin, NSW. The work is part of an ongoing Geochronology Project, conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework (NCF) agreement, to better understand the geological evolution and mineralisation history of the Cobar Basin. The results herein correspond to zircon U–Pb SHRIMP analysis undertaken by the GSNSW-GA Geochronology Project during the July 2018 – June 2019 reporting period.

This record presents new zircon U-Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP) for eleven samples of plutonic and volcanic rocks from the Lachlan Orogen, and the New England Orogen. The work is part of an ongoing Geochronology Project (Metals in Time), conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework (NCF) agreement, to better understand the geological evolution of New South Wales. The results herein (summarised in Table 1.1 and Table 1.2) correspond to zircon U-Pb SHRIMP analysis undertaken on GSNSW mineral systems projects for the reporting period July 2015-June 2016. Lachlan Orogen In the Lachlan Orogen, the age of 418.9 ± 2.5 Ma for the Babinda Volcanics is consistent with the accepted stratigraphy of its parent Kopyje Group, agrees with the ages of other I-type volcanic rocks within the Canbelego-Mineral Hill Volcanic Belt and indicates eruption and emplacement of this belt during a single event. The age of the Shuttleton Rhyolite Member (421.9 ± 2.7 Ma) of the Amphitheatre Group is compatible with recent U-Pb dating of the Mount Halfway Volcanics, which interfingers with the Amphitheatre Group (MacRae, 1987). The age is also similar to nearby S-type granite intrusions, which suggests that the limited eruptive volcanic activity in the region was accompanied by local coeval plutonism. The results for the Babinda Volcanics and Shuttleton Rhyolite Member, in conjunction with previous GA dating and other dating and studies (summarised in Downes et al., 2016) establishes that significant igneous activity occurred between ~423 and ~418 Ma within the Cobar region but comprised two compositionally distinct but broadly contemporaneous belts of volcanics and comagmatic granite intrusions. The new age for the unnamed quartz monzonite at Hobbs Pipe constrains the maximum age of the hosted gold mineralisation to 414.7 ± 2.6 Ma. The wide range in ages for granites along the Gilmore Suture suggests that mineralisation in this region is not necessarily constrained to a single short-lived event. The new age of 413.5 ± 2.3 Ma for volcanics at Yerranderie indicates that that the Bindook Volcanic Complex was erupted over a relatively short period, and also indicates that the epithermal mineralisation at Yerranderie was not genetically related to the host volcanics but probably to a younger rifting event in the east Lachlan. New England Orogen Four units were dated from the Clarence River Supersuite in the New England Orogen. All four are between 255 and 256 Ma, demonstrating that these granites are related chemically, spatially, and temporally. While these four ages are indistinguishable, the current age span for Clarence River Supersuite is more than 40 million years. This wide age range indicates that classification of granites into the Clarence River Supersuite needs further refinement. The new age for the Newton Boyd Granodiorite (252.8 ± 1.0 Ma) is similar to some previously dated units within the Herries Supersuite, but both the Herries Supersuite and Stanthorpe Supersuite (into which the Herries Supersuite was reclassified by Donchak, 2013) incorporate units with a broad range of ages: the age distribution for the Stanthorpe Supersuite spans 50 million years. Classification of granites in the New England Orogen in New South Wales is worth revisiting. Two units were dated from the Drake Volcanics, nominally in the Wandsworth Volcanic Group and indicate that the middle to upper section of the Drake Volcanics, including the mineralising intrusions, were emplaced within the space of 1-2 million years. These results support a genetic and temporal link between the Au-Ag epithermal mineralisation at White Rock and Red Rock and their host Drake Volcanic packages rather than to younger regional plutonism (i.e., Stanthorpe Supersuite) or volcanism (i.e., Wandsworth Volcanics). The almost 10 Ma gap between the Drake Volcanics and the next lowest units of the Wandsworth Volcanic Group supports the argument for considering the Drake Volcanics a distinct unit.

This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP), and thin section descriptions for four samples of plutonic and sedimentary rocks from the Captains Flat 1:50, 000 special map sheet, Eastern Lachlan Orogen, New South Wales. The work was carried out under the auspices of the National Geoscience Accord, as a component of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) during the reporting periods 2012 and 2013. The four samples (Table 1.1 and Figure 1.1) were collected from CANBERRA (small and large capitals refer to map sheet names in the 1:100 000 and 1:250 000 Topographic Series respectively); one sample from CANBERRA (northcentral CANBERRA), two from MICHELAGO (southcentral CANBERRA) and one from ARALUEN (southcentral CANBERRA).

New SHRIMP U-Pb zircon ages from the New England Orogen, New South Wales July 2014-June 2015

The late Permian Wandsworth Volcanic Group (WVG) in the southern New England Orogen (SNEO) is dominated by a monotonous series of amalgamated rhyodacitic to felsic eruptives, with minor interbedded flows, intrusives and sediments. The area enclosing known exposures of the WVG cover more than 30,000 km2, with a minimum thickness of 2 km. The top of the succession, as well as the vast majority of the pile representing non-welded material, has not been preserved. Field relationships indicate a broadly contemporaneous (though not necessarily genetic) relationship with late Permian granite magmatism, while Triassic plutons (typically in the range 246-243 Ma) intrude the WVG. SHRIMP U-Pb zircon dating indicates ages around 256.4 ± 1.6 Ma for basal units of the WVG, and 254.1 ± 2.2 Ma for the youngest preserved member of the WVG (Dundee Rhyodacite), defining a short period of substantial intermediate to acid eruptive volcanism. The compositionally unevolved Drake Volcanics to the northeast are older (264.4 ± 2.5 Ma) while those at Halls Peak are older still (Early Permian). Granites of the I-type Moonbi and Uralla Supersuites are dominantly 256-251 Ma and thus overlap in timing (and space) with the WVG event. Interestingly, many mineralized leucogranites (e.g. Parlour Mountain, Oban River, Gilgai) which were formerly regarded as Triassic are now established as synchronous with the Moonbi and Uralla Supersuites and the WVG. The age range of eruption of the WVG permitted by the SHRIMP results (~6 Ma) has been further constrained by CA-ID-TIMS U-Pb zircon analysis which yielded oldest and youngest ages of 255.54 ± 0.16 Ma and 253.26 ± 0.15 Ma respectively, indicating a maximum eruptive time range of ~2 Ma for the preserved pile. Our new results coincide with those determined from CA-ID-TIMS dating of tuffs in the Sydney and Gunnedah Basins. WVG exposures at Attunga are exactly (within ~0.1 Ma) coincident with the age of tuffs within the Trinkey Formation located in the Gunnedah Basin to the west, and the Dundee Rhyodacite is similarly closely matched to the thick Awaba Tuff in the Sydney Basin. Notably, much of the late Permian volcanic and plutonic magmatism in the SNEO is restricted to a remarkably small time range, which coincides exactly with the range of ash fall events in the Sydney and Gunnedah Basins, and possibly further afield. This suggests the SNEO, and the WVG in particular, was the dominant source of volcanic material erupted into these adjacent basins. Further, the adjacent basins may provide a more complete record of Permo-Triassic magmatism in the SNEO than currently preserved within the orogen itself.