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 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>.

The Roebuck Basin is on Australia’s North West Shelf, between the Browse and northern Carnarvon basins. The basin consists of Paleozoic to recent fluvial to deep marine mudstones and sandstones, carbonate platforms and reefs, and volcaniclastics. Recent hydrocarbon discoveries in the Bedout Sub-basin have renewed exploration interest and changed existing perceptions about the regions prospectivity. The interpretation of U-Pb detrital zircon dating from offshore petroleum well cuttings provides new information regarding the origin of sediments and changes in sediment provenance. This analytical work has the potential to better understand reservoir quality within the Triassic Upper and Lower Keraudren deltas (and equivalent sequences). A range of detrital zircon age spectra were obtained. Analyses of zircon grain shapes (i.e. roundness) somewhat supports transportation of some distance, but could also signify multi-phase recycling. However, the combined detrital age spectra and grain shape reveals that the Roebuck Basin deltas had multiple sediment sources. The Roebuck Basin’s Triassic sediments appear to be derived from Australia’s interior, potentially transported either directly via large rivers or from subsequent sediment reworking and transport via long-shore drift. Seismostratigraphic interpretations have identified potential sediment transport mechanisms including clinoforms and submarine canyons. Significant landward uplift and erosion associated with the latest Permian-aged Bedout Movement supports the reworking of Permian sediments. Integration of additional samples, and linking these to palaeogeographic settings, will provide additional clarity of the potential Australian and non-Australian Triassic sediment sources. This study aims to provide further insight into the origin of the reservoir units in the Roebuck Basin.

This Record presents new Sensitive High Resolution Ion Microprobe (SHRIMP) U–Pb geochronological results for samples collected from the Mary Kathleen Domain, which forms the western part of the Eastern Fold Belt in the Mount Isa Inlier. Eight samples, comprising three granites, one quartz diorite, two metarhyolites, one feldspathic quartzite, and one of matrix material from a breccia, have been analysed as part of ongoing investigations by GSQ in collaboration with researchers from James Cook University. The results enable a better understanding of the evolution of the domain, the associated magmatism, and any related mineralisation. <b>Bibliographic Reference:</b> Kositcin, N., Bultitude, R.J., and Purdy, D.J. Summary of Results. Joint GSQ–GA Geochronology Project: Mary Kathleen Domain, Mount Isa Inlier, 2018–2019. <i>Queensland Geological Record</i><b> 2019/02</b>.