<p>The Mesoproterozoic Roper Group of the McArthur Basin has excellent petroleum potential, but its poorly constrained post-depositional history has hampered resource exploration and management. The Derim Derim Dolerite occupies an important position in the regional event chronology, having intruded the Roper Group prior to deformation associated with the ‘Post-Roper Inversion’ event. It was assigned a magmatic crystallisation age of 1324 ± 4 Ma (uncertainties are 95% confidence unless otherwise indicated) in 1997, based on unpublished Sensitive High Resolution Ion Micro Probe (SHRIMP) U-Pb analyses of dolerite-hosted baddeleyite from sample 97106010, collected from the Derim Derim Dolerite type locality in outcrop within the northwestern McArthur Basin. Herein, we refine these data via Isotope Dilution-Thermal Ionisation Mass Spectrometry (ID-TIMS) analysis of baddeleyites plucked from the SHRIMP grain-mounts, which yielded a precise mean 207Pb/206Pb date of 1327.5 ± 0.6 Ma. This date is significantly older than a baddeleyite U-Pb ID-TIMS date of 1313.8 ± 1.3 Ma recently obtained from dolerite ALT-05, sampled in Pacific Oil and Gas Ltd drillhole Altree 2, near the northern margin of the Beetaloo Sub-basin, and 200 km south of 97106010. This pair of results indicates that Derim Derim Dolerite magmatism spanned at least 10-15 Ma. Previously documented geochemical variation in Mesoproterozoic mafic rocks across the Northern Territory (such as the 1325 ± 36 Ma (2σ) Galiwinku Dolerite in the northern McArthur Basin, 1316 ± 40 Ma phonolites intruding the eastern Pine Creek Orogen, and 1295 ± 14 Ma gabbro in the Tomkinson Province) may reflect episodic pulses of magmatism hitherto obscured by the low precision of the available isotopic dates. <p><b>Citation:</b> Bodorkos, S., Yang, B., Collins, A.S., Crowley, J., Denyszyn, S.W., Claoue-Long, J.C., Anderson, J.R. and Magee, C., 2020 Precise U–Pb baddeleyite dating of the Derim Derim Dolerite: evidence for episodic mafic magmatism in the greater McArthur Basin. 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 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 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>.

The EARTHTIME initiative has enabled improvements in high-precision ID-TIMS U-Pb geochronology, demonstrating SI-traceable calibrations with rigorous uncertainty estimation. In a similar fashion, the LA-ICP-MS U-Pb community have reassessed their uncertainty estimation and workflow to try to harmonise better practice in quantification and interpretation across the community. The SHRIMP community has a current imperative to rewrite its data handling software providing an opportunity to review ion-microprobe U-Pb workflow and uncertainty estimation methods. This work will provide the perfect platform to integrate SHRIMP U-Pb dating practices with more recent data handling approaches to ensure harmony and comparability of output between SHRIMP, LA-ICP-MS and ID-TIMS methods. SHRIMP and LA-ICP-MS data acquisition and processing appear to be very similar. Both methods are relative techniques, requiring calibration to matrix-matched primary reference materials analysed under the same conditions at the same time. Measurement uncertainties are similar, calibration requirements are similar and potential system drift has similar effects and impact on data and concomitant uncertainty estimation. For these and other reasons, we are interrogating SHRIMP and recently published LA-ICP-MS U-Pb data handling workflows to compare approaches, learn mutual lessons, and understand the uncertainty propagation requirements of each method such that a complete understanding of the comparability of U-Pb data obtained by the two methods can be ascertained. We will highlight results to date in describing the SHRIMP and LA-ICP-MS U-Pb data handling workflows in tandem allowing data comparison between the two methods to be properly quantified thereby enabling direct quantification and comparison with ID-TIMS reported ages. In this way, U-Pb geochronology will be a more rigorously applied tool from the highest spatial resolution to highest precision, expanding and building on the EARTHTIME initiative to date. This abstract was submitted to/presented at the 2017 Goldschmidt Conference (https://goldschmidt.info/2017/)

This Record presents new Sensitive High Resolution Ion Micro Probe (SHRIMP) U–Pb geochronological results from the Aileron Province that were obtained during the Northern Territory Geological Survey–Geoscience Australia (NTGS–GA) geochronology project under the National Collaboration Framework (NCF) agreement, in July 2020. Geoscience Australia’s contribution to this project forms part of the Exploring for the Future (EFTF) Program, which aims to better understand the mineral, energy, and groundwater resources of Northern Australia. <b>Bibliographic Reference:</b> Kositcin N, Beyer EE and Reno BL, 2021. Summary of results. Joint NTGS–GA geochronology project: Aileron Province, Jinka and Dneiper 1:100 000 mapsheets, 2020. <i>Northern Territory Geological Survey, Record</i><b> 2021-008</b>.

This Record presents new Sensitive High Resolution Ion Micro Probe (SHRIMP) U–Pb geochronological results for six 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 better understand the geological evolution and mineral potential of this region. SHRIMP U–Pb detrital zircon results from two samples, a meta-siltstone/mudstone from the Au–Cu–Bi Rover 1 deposit (drillhole WGR1D011; sample BW20PGF090) and a volcaniclastic sandstone from the Explorer 142 prospect (drillhole NR142D001; sample BW20PGF156) gave near identical maximum depositional ages of 1849.1 ± 3.1 Ma and 1848.9 ± 3.0 Ma respectively. The euhedral nature of the zircons in both samples and their unimodal age distributions, support the interpretation that the maximum depositional ages of these samples are good approximations for their true age of deposition. These results are a very close match with U–Pb zircon geochronology of some other drill core samples from the Rover mineral field. Two magmatic rocks from drillhole RVDD0002 (located in the East of the Rover field), gave ages of ca 1851–1850 Ma, while a volcaniclastic sandstone from RVDD0002 gave a maximum depositional age of 1854.0 ± 2.9 Ma (Cross et al 2021). Our new results from drillholes WGR1D011 and NR142D001 confirm the widespread presence of detrital zircons at ca 1854–1849 Ma across much of the Rover mineral field. SHRIMP U–Pb detrital zircon analysis was undertaken on four samples from the base metal Curiosity prospect drillhole, MXCURD002. The first sample analysed GS20PGF058 [520.0–525.7 m], has a maxima at ca 1842 Ma but youngest statistical grouping at 1729 ± 17 Ma (n = 6). This is in stark contrast with a previous sample from this drillhole (GS19DLH0056 [437.63–438.18 m]) that is 82 metres above GS20PGF058, and gave a MDA of 1854.0 ± 2.9 Ma (Cross et al 2021). In an effort to further investigate the ca 1729 Ma date given by GS20PGF058, three further samples were collected from drillhole MXCURD002, one sample below, GS20PGF190 [525.7–531.5 m] and two samples above, GS20PGF085 [515.0–520.0 m] and GS20PGF084 [468.1–473.45 m]. Additionally, samples GS20PGF190 and GS20PGF085 are continuations of the same meta-siltstone/mudstone unit sampled by GS20PGF058. These three samples returned maximum depositional ages of 1851.7 ± 3.9 Ma (GS20PGF085), 1846.6 ± 3.2 Ma (GS20PGF190) and 1841 ± 12 Ma (GS20PGF084). They are also indistinguishable within their uncertainties (MSWD = 0.71, POF = 0.49) and have an average date of ca 1848 Ma. Therefore, the evidence from SHRIMP U–Pb detrital zircon studies of four rocks from drillhole MXCURD002 (this study and that of Cross et al 2021), indicates that the metasedimentary rocks in MXCURD002 were probably deposited at ca 1850 Ma, similar to other metasedimentary units within the Rover mineral field. We suggest that the relatively younger statistical grouping in sample GS20PGF058 at ca 1730 Ma is possibly the result of isotopic re-setting due to a thermal and/or fluid event associated with lead–zinc–copper mineralisation at a similar time which has been recently reported by Farias et al (2022). Although other explanations to explain the ca 1730 Ma grains in this sample such as laboratory contamination or that the zircons have in fact preserved their original crystallisation age, cannot be ruled out. <b>Bibliographic Reference:</b> Cross AJ, Farias PG and Huston DL, 2022. Summary of results. Joint NTGS–GA geochronology project: Rover mineral field, Warramunga Province, July–December 2020. <i>Northern Territory Geological Survey</i>, <b>Record 2022-005</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 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 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>.

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