The Mesoproterozoic South Nicholson Basin sits between, and overlies, the Paleoproterozoic Mount Isa Province to the east and the southern McArthur Basin to the northwest. The McArthur Basin and Mount Isa Province are well studied and highly prospective for both mineral and energy resources. In contrast, rocks in the South Nicholson region (incorporating the Mount Isa Province, the Lawn Hill Platform and the South Nicholson Basin, and geographically straddling the Northern Territory and Queensland border) are mostly undercover, little studied and consequently relatively poorly understood. A comprehensive U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon and xenotime geochronology program was undertaken to better understand the stratigraphy of the South Nicholson region and its relationship to the adjacent, more overtly prospective Mount Isa Province and McArthur Basin. The age data indicate that South Nicholson Basin deposition commenced ca. 1483 Ma, with cessation at least by ca. 1266 Ma. The latter age, based on U-Pb xenotime, is interpreted as the timing of postdiagenetic regional fluid flow. The geochronology presented here provides the first direct age data confirming that the South Nicholson Group is broadly contemporaneous with the Roper Group of the McArthur Basin. Some rocks, mapped previously as Mesoproterozoic South Nicholson Group and comprising proximal, immature lithofacies, have detrital spectra consistent with that of the late Paleoproterozoic McNamara Group of the western Mount Isa Province; this will necessitate a revision of existing regional stratigraphic relationships. The stratigraphic revisions and correlations proposed here significantly expand the extent of highly prospective late Paleoproterozoic stratigraphy across the South Nicholson region, which, possibly, extends even further west beneath the Georgina and Carpentaria basins. Our data and conclusions allow improved regional stratigraphic correlations between Proterozoic basins, improved commodity prospectivity and targeted exploration strategies across northern Australia. <b>Citation:</b> Carson, C.J., Kositcin, N., Anderson, J.R., Cross, A. and Henson, P.A., 2020. New U–Pb geochronology for the South Nicholson region and implications for stratigraphic correlations.. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This Record presents new U-Pb geochronological data, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), from six samples of igneous rocks and four samples of sedimentary rocks, collected from south-central New South Wales. 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 of the central Lachlan Orogen in the East Riverina region. The results presented herein correspond to the reporting period July 2015-June 2016.

This Record contains new zircon U-Pb geochronological data, obtained via Sensitive High-Resolution Ion Micro Probe (SHRIMP), from two samples of metamorphosed felsic igneous rocks of the Proterozoic Pinjarra Orogen (Western Australia), intersected in diamond drillcore at the base of deep petroleum exploration wells penetrating the Paleozoic sedimentary successions of the Perth Basin. In the southern Perth Basin, petroleum exploration well Sue 1 was terminated at depth 3074.2 m, in crystalline basement rocks of the southern Pinjarra Orogen. Abundant zircon from a biotite-bearing felsic orthogneiss at depth 3073.2-3073.7 m yielded a complex array of U-Pb isotopic data, indicative of significant post-crystallisation disturbance of the isotopic system. A Discordia regression fitted to the array yielded an upper intercept date of 1076 ± 35 Ma (all quoted uncertainties are 95% confidence intervals unless specified otherwise) interpreted to represent magmatic crystallisation of the igneous precursor to the orthogneiss, and a lower intercept date of 680 ± 110 Ma which is our best estimate of the age of the tectonothermal event responsible for post-crystallisation disturbance of the U-Pb system. Crust of known Mesoproterozoic age is rare in the southern Pinjarra Orogen: pre-1000 Ma igneous crystallisation ages in the Leeuwin Complex were previously known only from two c. 1090 Ma garnet-bearing orthogneisses at Redgate Beach (Nelson, 1999), 30 km west of Sue 1. All other dated outcrops have revealed Neoproterozoic (780-680 Ma) granitic protoliths reworked by Early Cambrian (540-520 Ma) magmatism, deformation and metamorphism (Nelson, 1996, 2002; Collins, 2003). In the northern Perth Basin, petroleum exploration well Beagle Ridge 10A was terminated at depth 1482 m, in crystalline basement rocks of the northern Pinjarra Orogen. A leucocratic orthogneiss sampled within the interval 1464.0-1467.0 m yielded only sparse zircon, but four of the seven grains analysed yielded a weighted mean 207Pb/206Pb date of 1092 ± 27 Ma, interpreted to represent magmatic crystallisation of the igneous precursor to the orthogneiss. Our data show no evidence for Neoproterozoic U-Pb resetting of the c. 1090 Ma zircons: where present, post-crystallisation isotopic disturbance is predominantly geologically recent. The two newly dated samples are located at opposite ends of the Perth Basin (about 470 km apart), and although the two magmatic crystallisation ages are imprecise, the date of 1092 ± 27 Ma from the Beagle Ridge 10A leucocratic orthogneiss is indistinguishable from the date of 1076 ± 35 Ma from the Sue 1 felsic orthogneiss. Furthermore, both rocks contain inherited zircon of Mesoproterozoic age (1620-1180 Ma in Sue 1; 1290-1210 Ma in Beagle Ridge 10A), indicating the presence of pre-1100 Ma crustal components in their parent magmas. This is consistent with a suite of Paleoproterozoic Sm-Nd model ages determined by Fletcher et al. (1985) on buried Pinjarra Orogen orthogneisses, which span 2.01 ± 0.06 Ga to 1.78 ± 0.04 Ga in the north (near BMR Beagle Ridge 10A), and including a model age of 1.80 ± 0.04 Ga from a sample of granitic gneiss obtained from Sue 1. Fletcher et al. (1985) argued that the consistency of 2.1-1.8 Ga Nd model ages obtained from crystalline basement in drillcore beneath the southern and northern Perth Basin, and from outcrop in the Northampton Complex and Mullingarra Complex of the northern Pinjarra Orogen, indicated a similar or shared crustal evolution. Our new U-Pb zircon data support this model, expanding the known extent of 1100-1050 Ma felsic magmatism in both the southern and northern Pinjarra Orogen, and indicating that Neoproterozoic tectonothermal overprinting appears to be restricted to the Leeuwin Complex, with no corresponding event discernible in the northern Pinjarra Orogen.

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 Record presents new Sensitive High Resolution Ion MicroProbe (SHRIMP) U-Pb zircon results from the Mount Isa Orogen obtained under the auspices of the Geological Survey of Queensland-Geoscience Australia (GSQ-GA) National Collaboration Framework (NCF) geochronology project between July 2016 and June 2017. New results are presented from eight samples collected as part of ongoing regional mapping and geoscientific programs in the Mount Isa Orogen. GA work presented here represents part of the federally funded Exploring for the Future Program. As a part of ongoing geological mapping in the Mount Isa Orogen, the Geological Survey of Queensland (GSQ) and Geoscience Australia (GA) have undertaken a geochronology program to enhance the understanding of the geological evolution of the province. There are two focus areas as a part of this Record. The first focus area is north of Mount Isa, in the Kalkadoon-Leichhardt and Sybella domains (Figure i), and includes geochronology results from three mafic to intermediate rocks. The second focus area is south of Cloncurry, in the Kuridala–Selwyn and Marimo–Staveley domains (Figure i), and includes geochronology results from one leucogranite and four sedimentary rocks. For ease of reporting, these two focus areas are split into two themes 1) ‘mafic rocks’ for the three geochronology results north of Mount Isa; and 2) ‘Kuridala–Selwyn corridor’ for the five geochronology results south of Cloncurry. <b>Bibliographic Reference:</b> LEWIS, C.J., WITHNALL, I.W., HUTTON, L.J., BULTITUDE, R.J., SLADE, A.P., SARGENT, S., 2020. Summary of results. Joint GSQ–GA geochronology project: Mount Isa region, 2016–2017. <i>Queensland Geological Record</i><b> 2020/01</b>.

This Record presents data collected in September 2019 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia (NTGS–GA) SHRIMP geochronology project under the National Collaborative Framework (NCF) agreement and Geoscience Australia's Exploring for the Future (EFTF) Program. Two new U–Pb SHRIMP zircon geochronological results derived from two samples of the Balbirini Dolostone (southern McArthur Basin, Northern Territory) are presented herein. The Balbirini Dolostone is part of the early Mesoproterozoic Nathan Group, and is a thick unit of interbedded dolostone and dolomitic siliciclastic rocks that include evaporitic redbeds. The two samples were collected in June 2019 from the type section of the Balbirini Dolostone in southern BAUHINIA DOWNS (MALLAPUNYAH). <b>Bibliographic Reference:</b> Kositcin N, and Munson TJ, 2020. Summary of results. Joint NTGS–GA geochronology project: Balbirini Dolostone, southern McArthur Basin, June 2019–September 2019. <i>Northern Territory Geological Survey</i>, <b>Record 2020-002</b>.

This Record presents new Sensitive High Resolution Ion MicroProbe (SHRIMP) U–Pb zircon results obtained under the auspices of the Geological Survey of Queensland–Geoscience Australia (GSQ–GA) National Collaboration Framework (NCF) geochronology project between July 2016 and June 2017. This Record presents results from six newly analysed samples, in support of ongoing regional mapping and geoscientific programs led by GSQ in the Georgetown, Coen and Cairns regions. Three magmatic samples were analysed from unnamed rhyolite dykes within the Georgetown region (Gilberton 1:250 000 sheet SE5416), two samples (one magmatic and one metasedimentary) from the Coen region(Coen SD5408), and one metasedimentary sample from the Cairns region (Innisfail SE5506). A summary of each sample is presented, each containing information on sample location and geological content, geochronology results, as well as a brief geochronological interpretation. <b>Bibliographic Reference:</b> Christopher J. Lewis, Courteney R. Dhnaram, Dominic D. Brown, Robert J. Bultitude, Vladimir A. Lisitsin. Summary of Results. Joint GSQ–GA Geochronology Project: Georgetown, Coen and Cairns regions, 2016–2017. <i>Queensland Geological Record</i><b> 2021/05</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 data collected in July–August 2020 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia SHRIMP geochronology project under the National Collaboration Framework agreement and Geoscience Australia's Exploring for the Future Program. New U–Pb SHRIMP zircon geochronological results derived from eight sedimentary samples from the western Amadeus Basin in the Northern Territory are presented herein. Detrital zircon U–Pb ages were determined from four samples of the Winnall Group: three samples of the Liddle Formation and one of the Puna Kura Kura Formation. Zircon U–Pb ages were also determined from two samples of the Pertaoorrta Group (Cleland Sandstone and Tempe Formation), one sample of the Larapinta Group (Stairway Sandstone) and one sample of the Mereenie Sandstone. <b>Bibliographic Reference:</b> Kositcin N, Verdel C, Normington VJ and Simmons JM, 2021. Summary of results. Joint NTGS–GA geochronology project: western Amadeus Basin, July–August 2020. <i>Northern Territory Geological Survey, Record</i> <b>2021-002</b>.

This Record presents data collected between March and September 2018 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia (NTGS–GA) SHRIMP geochronology project under the National Collaborative Framework (NCF) agreement and Geoscience Australia's Exploring for the Future Programme. Five new U–Pb SHRIMP zircon geochronological results derived from five samples of meta-igneous and metasedimentary rocks from MOUNT RENNIE (southwestern Aileron Province and northwestern Warumpi Province) in the Northern Territory are presented herein. All five samples are located at or close to the recently discovered greenfield Grapple and Bumblebee prospects that contain precious and base metal sulfide mineralisation. This Record represents the first attempt to provide temporal constraints on the country rocks that host or occur close to this mineralisation. <b>Bibliographic Reference:</b> Kositcin N, McGloin MV, Reno BL and Beyer EE, 2019. Summary of results. Joint NTGS–GA geochronology project: Cu-Au-Ag-Zn mineralisation in MOUNT RENNIE, Aileron and Warumpi provinces, March – September 2018. <i>Northern Territory Geological Survey</i>, <b>Record 2019-011</b>.