This Record presents new Sensitive High Resolution Ion Microprobe (SHRIMP) U–Pb geochronological results for samples collected from the Mount Isa Inlier and covered areas to the east. The Mary Kathleen Domain is the focus of this work and 11 metasedimentary and igneous samples were analysed from across the distribution of the domain. An additional two metasedimentary samples and one igneous sample from drill cores located east of the outcropping Mount Isa Province were also analysed. <b>Bibliographic Reference: </b>Kositcin, N., Purdy, D.J., Bultitude, R.J., Brown, D.D. & Hoy, D. Summary of Results. Joint GSQ–GA Geochronology Project: Mary Kathleen Domain and rocks under younger cover east of the Mount Isa Inlier, 2019–2020. <i>Queensland Geological Record</i><b> 2021/01</b>.

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.

Radiogenic isotopes decay at known rates and can be used to interpret ages for minerals, rocks and geologic processes. Different isotopic systems provide information related to different time periods and geologic processes, systems include: U-Pb and Ar/Ar, Sm-Nd, Pb-Pb, Lu-Hf, Rb-Sr and Re-Os isotopes. The GEOCHRON database stores full analytical U-Pb age data from Geoscience Australia's (GA) Sensitive High Resolution Ion Micro-Probe (SHRIMP) program. The ISOTOPE database is designed to expand GA's ability to deliver isotopic datasets, and stores compiled age and isotopic data from a range of published and unpublished (GA and non-GA) sources. OZCHRON is a depreciated predecessor to GEOCHRON and ISOTOPE, the information once available in OZCHRON is in the process of migration to the two current databases. The ISOTOPE compilation includes sample and bibliographic links through the A, FGDM, and GEOREF databases. The data structure currently supports summary ages (e.g., U-Pb and Ar/Ar) through the INTERPRETED_AGES tables, as well as extended system-specific tables for Sm-Nd, Pb-Pb, Lu-Hf and O- isotopes. The data structure is designed to be extensible to adapt to evolving requirements for the storage of isotopic data. ISOTOPE and the data holdings were initially developed as part of the Exploring for the Future (EFTF) program - particularly to support the delivery of an Isotopic Atlas of Australia. During development of ISOTOPE, some key considerations in compiling and storing diverse, multi-purpose isotopic datasets were developed: 1) Improved sample characterisation and bibliographic links. Often, the usefulness of an isotopic dataset is limited by the metadata available for the parent sample. Better harvesting of fundamental sample data (and better integration with related national datasets such as Australian Geological Provinces and the Australian Stratigraphic Units Database) simplifies the process of filtering an isotopic data compilation using spatial, geological and bibliographic criteria, as well as facilitating 'audits' targeting missing isotopic data. 2) Generalised, extensible structures for isotopic data. The need for system-specific tables for isotopic analyses does not preclude the development of generalised data-structures that reflect universal relationships. GA has modelled relational tables linking system-specific Sessions, Analyses, and interpreted data-Groups, which has proven adequate for all of the Isotopic Atlas layers developed thus far. 3) Dual delivery of 'derived' isotopic data. In some systems, it is critical to capture the published data (i.e. isotopic measurements and derived values, as presented by the original author) and generate an additional set of derived values from the same measurements, calculated using a single set of reference parameters (e.g. decay constant, depleted-mantle values, etc.) that permit 'normalised' portrayal of the data compilation-wide. 4) Flexibility in data delivery mode. In radiogenic isotope geochronology (e.g. U-Pb, Ar-Ar), careful compilation and attribution of 'interpreted ages' can meet the needs of much of the user-base, even without an explicit link to the constituent analyses. In contrast, isotope geochemistry (especially microbeam-based methods such as Lu-Hf via laser ablation) is usually focused on the individual measurements, without which interpreted 'sample-averages' have limited value. Data delivery should reflect key differences of this kind. <b>Value: </b>Used to provide ages and isotope geochemistry data for minerals, rocks and geologic processes. <b>Scope: </b>Australian jurisdictions and international collaborative programs involving Geoscience Australia

This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP) for five samples of plutonic and volcanic rocks from the central Lachlan Orogen and the Thomson 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 2011-2012.

This Record contains new zircon U-Pb geochronological data obtained via Sensitive High-Resolution Ion Micro Probe (SHRIMP) from 19 samples of volcanic and plutonic igneous rocks of the central and eastern Lachlan Orogen, New South Wales. These data were obtained during the reporting period July 2013-June 2014, under the auspices of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA), which is part of the National Geoscience Accord.

The accessory mineral zircon is the most widely used geological timekeeper and tracer of crustal growth processes. Specifically, U-Pb isotopes in zircon offer a means to accurately determine the timing of magmatic events and their Hf isotopic composition provides a means to constrain magma source composition and potentially approximate source age. The high spatial resolution provided by in situ techniques such as secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) have the advantage of being able to target different growth zones within individual zircon crystals, and unravel complex magmatic histories. However, utilising this power effectively requires calculation of accurate initial Hf compositions, which are founded on the assumption that the information obtained via the U-Pb and Lu-Hf systems are correctly integrated. A typical Hf isotope LA-ICP-MS analysis ablates a sample volume that is two orders of magnitude greater than a typical SIMS analysis. Thus, when age determination has been carried out by SIMS it is necessary to demonstrate that each subsequent Hf isotope analysis has sampled a similar isotopically homogeneous volume. Here, we use a combined SIMS and laser ablation split stream (LASS)-ICP-MS approach, whereby U-Pb isotopic measurement concurrently on the same sample volume as the Hf isotope measurement is compared to prior lower volume SIMS measurements. Using a suite of new drill core magmatic rock samples from the comparatively unexplored Coompana Province in South Australia, we demonstrate how such an approach can be used to filter Hf isotope datasets by identifying LA-ICP-MS analyses that sampled mixtures of different zircon growth domains. The robust initial 176Hf/177Hf compositions obtained from the filtered Coompana data set indicate that the province represents part of a juvenile Paleoproterozoic-Mesoproterozoic arc system formed through hyperextension of the margin of the Archean Gawler Craton, which can be correlated to the Musgrave Province and Madura Province in central and western Australia respectively. This hyperextension process is temporally similar to that on the now-adjacent Archean Yilgarn Craton margin.

This Record presents six previously unpublished U–Pb SHRIMP zircon geochronological results from the Aileron Province in the Northern Territory. The data was collected to investigate the timing of localised and poorly documented granulite facies high-T, low-P metamorphism across isolated outcrops in the central and western Aileron Province. The study was also designed to test the maximum deposition ages of the metasedimentary rocks across this large area, and whether the data are consistent with the samples being high-grade equivalents of the Lander Rock Formation. <b>Bibliographic Reference:</b> Kositcin N, and Scrimgeour IR, 2020. Summary of results: Joint NTGS–GA geochronology project: central and western Aileron Province. <i>Northern Territory Geological Survey</i>, <b>Record 2020-011</b>.

This work is a part of an investigation of mineralisation associated with the extensive Kennedy Igneous Association (Champion & Bultitude, 2013) in North Queensland. This part of the project involves U–Pb zircon geochronology of magmatic rocks that are associated with gold mineralisation. By doing this we hope to identify key time-periods of magmatic activity that can be used by explorers to better focus their exploration efforts and assist with the development of new tectono-metallogenic models. Earlier results published by Cross et al. (2019) and Kositcin et al. (2016) in the Jardine Subprovince of the Kennedy Igneous Association in Cape York, for the first time, demonstrated a strong association between gold mineralisation and early Permian (285–280 Ma) felsic dykes that intrude either Proterozoic metamorphic rocks or Devonian granites of the Cape York Batholith. The SHRIMP U–Pb zircon results reported here come from three magmatic rocks, Badu Granite (2678819/QFG8689E), Horn Island Granite (2678820/QFG8800A) and unnamed rhyolite (2678818/QFG8798A), that were sampled from exploration drill core, drilled by Alice Queen Limited on behalf of its subsidiary company, Kauraru Gold Pty Ltd between 2016 and 2017 on the western margins of the historic Horn Island gold mine. Prior to this work, magmatic rocks of the Badu Supersuite on Horn Island were attributed to the Jardine Subprovince of the Kennedy Igneous Association (Champion & Bultitude 2013). The Badu Supersuite comprises the Badu Suite (Badu Granite, Horn Island Granite and unmineralised porphyritic dykes; von Gnielinski et al., 1997) and the Torres Strait Volcanic Group. Gold mineralisation on Horn Island is intrusion-related and occurs within narrow quartz veins that contain native gold and sulphide mineralisation (Alice Queen Limited, 2021) that cut both the Badu and Horn Island granites but not the late-stage porphyritic dykes (von Gnielinski, 1996; von Gnielinski et al., 1997). Historical K–Ar ages from 286–302 Ma for Badu Suite intrusives (Richards and Willmott, 1970) were used to imply a late Carboniferous to early Permian age for the Torres Strait Volcanic Group. Recently however, two units from the Torres Strait Volcanic Group, the Endeavour Strait Ignimbrite and the ‘Bluffs Quarry’ rhyolite dyke yielded SHRIMP 206Pb/238U ages of 349.2 ± 3.1 Ma (Cross et al., 2019) and 353.4 ± 2.2 Ma (Kositcin et al., 2016), respectively, placing this group in the early Carboniferous. Two of the samples, the Badu Granite (2678819/QFG8689E) and Horn Island Granite (2678820/QFG8800A) gave indistinguishable 206Pb/238U results within analytical uncertainty (MSWD = 1.6, POF = 0.21) of 342.8 ± 1.9 Ma and 344.4 ± 1.7 Ma, respectively. The unmineralised, cross cutting, unnamed rhyolite (2678818/QFG8798A) has a significantly younger 206Pb/238U age of 309.9 ± 1.5 Ma. These results demonstrate that the Badu Granite and Horn Island Granite are early Carboniferous in age and not early Permian as previously thought. The historical K–Ar ages (302–286 Ma) for Badu Suite intrusives are interpreted to record thermal resetting. Together with the ca 350 Ma crystallisation ages for two units from the Torres Strait Volcanic Group (Cross et al., 2019; Kositcin et al., 2016), these new results reveal that magmatic crystallisation ages for the Badu Supersuite range between ca 350 Ma and 310 Ma. As such, the Badu Supersuite, along with the Black Cap Diorite (350.7 ± 1.3 Ma; Murgulov et al., 2009) near Georgetown, represents the earliest phase of magmatism associated with the early Carboniferous to late Permian, Kennedy Igneous Association. Consequently, the Badu Supersuite including the Badu Suite and the Torres Strait Volcanic Group are now seen to belong to a newly named Torres Strait Subprovince, which is distinctly older than the Jardine Subprovince on Cape York Peninsula. Additionally, these results constrain the timing of gold mineralisation at Horn Island to between a maximum age at ca 344 Ma provided by the host granites and a minimum age at ca 310 Ma constrained by the rhyolite dyke (2678818/QFG8798A). These constraints for the timing of gold mineralisation at Horn Island are further supported by unpublished results presented by Lisitsin & Dhnaram (2019a, b). These workers mention preliminary ca 342–344 Ma Re–Os molybdenite ages from two samples of quartz-molybdenite veins that cut the Badu Granite and an Ar–Ar age from sericite alteration associated with a quartz-sulphide-gold vein at ca 320 Ma that they considered to best represent the timing of gold mineralisation. The new SHRIMP U–Pb zircon ages presented here for magmatic rocks of the Badu Suite, reveal the association between gold mineralisation and early Carboniferous magmatism associated with the newly named Torres Strait Subprovince of the Kennedy Igneous Association.

This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP), and thin section descriptions for nine samples of plutonic and volcanic rocks of the New England 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 2010/11 and 2011/12.

This Record documents the efforts of Mineral Resources Tasmania (MRT) and Geoscience Australia (GA) in compiling a geochronology (age) compilation for Tasmania, describing both the dataset itself and the process by which it is incorporated into the continental-scale Isotopic Atlas of Australia. The Isotopic Atlas draws together age and isotopic data from across the country and provides visualisations and tools to enable non-experts to extract maximum value from these datasets. Data is added to the Isotopic Atlas in a staged approach with priorities determined by GA- and partner-driven focus regions and research questions. This Tasmanian compilation represents the second in a series of compilation publications (Records and Datasets) for the southern states of Australia, which are a foundation for the second phase of the Exploring for the Future initiative over 2020–2024. It was compiled primarily from data, reports, journal articles and theses provided to GA by MRT. The most current data can be accessed and downloaded from GA’s <a href=https://portal.ga.gov.au/persona/geochronology>EFTF Geochronology and Isotopes Data Portal</a> and MRT’s <a href=https://www.mrt.tas.gov.au/mrt_maps/app/list/map>LISTmap.</a>