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>.

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/)

<div>This Record presents data collected in March 2022–February 2023 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia SHRIMP geochronology project under the National Collaborative Framework agreement and Geoscience Australia’s <em>Exploring for the Future Program</em>. New U–Pb SHRIMP zircon geochronological results were derived from sedimentary rock chip samples of the Warburton Basin collected from four petroleum exploration wells (Beachcomber 1, Thomas 1, Simpson 1, Colson 1) in the southeastern corner of the Northern Territory. Geologically, this is a region in the Simpson Desert that encompasses several superimposed intracratonic sedimentary basins that are separated by regional unconformities that extend over areas of adjoining Queensland, South Australia and New South Wales. The exposed Mesozoic Eromanga Basin overlies the late Palaeozoic Pedirka Basin, which is largely restricted to the subsurface. The Warburton Basin is an early Palaeozoic pericratonic basin containing an early Cambrian and Ordovician succession (Edgoose and Munson, 2013), with possible Devonian rocks observed in some areas (Radke, 2009). As the Warburton Basin is entirely concealed beneath the Pedirka and Eromanga basins, our current understanding of the geology of the western Warburton Basin is constrained by the lack of surface exposures, the small number of well penetrations, limited biostratigraphic age control, and relatively sparse seismic data coverage. </div><div> The samples analysed herein were collected to aid in understanding the chronostratigraphy and provenance characteristics of the concealed Warburton Basin. All four sedimentary samples are dominated by Mesoproterozoic detritus (ca 1000–1300 Ma), have fewer zircons of Paleozoic age, and generally have sparse older Palaeoproterozoic–Archaean aged zircons. Samples from the two westernmost wells yielded 238U/206Pb maximum depositional ages of 469&nbsp;±&nbsp;9&nbsp;Ma (Colson 1) and 394&nbsp;±&nbsp;6&nbsp;Ma (Simpson 1). Samples from the two easternmost wells yielded older 238U/206Pb maximum depositional ages of 569&nbsp;±&nbsp;10&nbsp;Ma (Thomas 1) and 506&nbsp;±&nbsp;5&nbsp;Ma (Beachcomber 1). These data imply that known Devonian stratigraphy extends at least as far as the Simpson 1 well, but may not extend further east.</div><div><br></div><div>BIBLIOGRAPHIC REFERENCE: Kositcin N, Verdel C and Edgoose C, 2023. Summary of results. Joint NTGS–GA geochronology project: western Warburton Basin, March 2022–February 2023. <em>Northern Territory Geological Survey, Record </em>2023-006.</div><div><br></div><div><br></div>

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 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.

Database containing analytical data and interpretations from the Geoscience Geoscience (GA) geochronology program. Includes some legacy methods and externally sourced data. A collection of analytical data to support geochronology data or ages used in other reporting and publications.

<p>This record presents new zircon and titanite U–Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP) for twelve samples of plutonic and volcanic rocks from the Lachlan Orogen and the New England Orogen, and two samples of hydrothermal quartz veins from the Cobar region. Many of these new ages improve existing constraints on the timing of mineralisation in New South Wales, as 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. The results herein (summarised in Table 1.1 and Table 1.2) correspond to zircon and titanite U–Pb SHRIMP analysis undertaken on GSNSW mineral systems projects for the reporting period July 2016–June 2017. Lachlan Orogen <p>The Lachlan Orogen samples reported herein are sourced from operating mines, active prospects, or regions with historical workings. The new dates constrain timing of mineralisation by dating the units which host or crosscut mineralisation, thereby improving understanding of the mineralising systems, and provide stronger constraints for mineralisation models. <p>In the eastern Lachlan Orogen, the new dates of 403.9 ± 2.6 Ma for the Whipstick Monzogranite south of Bega, and 413.3 ± 1.8 Ma for the Banshea Granite north of Goulburn both provide maximum age constraints for the mineralisation they host (Whipstick gold prospect and Ruby Creek silver prospect, respectively). At the Paupong prospect south of Jindabyne, gold mineralisation is cut by a dyke with a magmatic crystallisation age of 430.9 ± 2.1 Ma, establishing a minimum age for the system. <p>The 431.1 ± 1.8 Ma unnamed andesite and the 428.4 ± 1.9 Ma unnamed felsic dyke at the Dobroyde prospect 10 km north of Junee are just barely distinguishable in age, in the order that is supported by field relationships. The andesite is the same age as the c. 432 Ma Junawarra Volcanics but has different geochemical composition, and is younger than the c. 437 Ma Gidginbung Volcanics. The two unnamed units pre-date mineralisation, and are consistent with Pb-dating indicating a Tabberaberran age for mineralisation at the Dobroyde gold deposit. <p>Similarly, the 430.5 ± 3.4 Ma leucogranite from Hickory Hill prospect (north of Albury) clarifies that this unit originally logged as Jindera Granite (since dated at 403.4 ± 2.6 Ma) is instead affiliated with the nearby Mount Royal Granite, which has implications for the extent of mineralisation hosted within this unit. <p>Cobar Basin <p>Titanite ages of 382.5 ± 2.6 Ma and 383.4 ± 2.9 Ma from hydrothermal quartz veins that crosscut and postdate the main phase of mineralisation at the Hera mine in the Cobar region constrain the minimum age for mineralisation. These ages are indistinguishable from a muscovite age of 381.9 ± 2.2 Ma interpreted to be related to late- or post-Tabberaberan deformation event, and these results indicate that mineralisation occurred at or prior to this deformation event. <p>New England Orogen <p>The new ages from granites of the New England Orogen presented in this record aid in classification of these plutons into various Suites and Supersuites, and these new or confirmed relationships are described in detail in Bryant (2017). Many of these plutons host mineralisation, so the new ages also provide maximum age constraints in the timing of that mineralisation. <p>The 256.1 ± 1.3 Ma age of the Deepwater Syenogranite 40 km north of Glen Innes indicates that it is coeval with the 256.4 ± 1.6 Ma (Black, 2006) Arranmor Ignimbrite Member (Emmaville Volcanics) that it intrudes, demonstrating that both intrusive and extrusive magmatism was occurring in the Deepwater region at the same time. The 252.0 ± 1.2 Ma age for the Black Snake Creek Granite northeast of Tenterfield is consistent with its intrusive relationship with the Dundee Rhyodacite (254.34 ± 0.34 Ma; Brownlow et al., 2010). Similarly, the 251.2 ± 1.3 Ma age for the Malara Quartz Monzodiorite southeast of Tenterfield is consistent with field relationships that demonstrate that it intrudes the Drake Volcanics (265.3 ± 1.4 Ma–264.4 ± 2.5 Ma, Cross and Blevin, 2010; Waltenberg et al., 2016). <p>The 246.7 ± 1.5 Ma Cullens Creek Granite north of Drake was dated in an attempt to provide a stronger age constraint on mineral deposits that also cut the Rivertree and Koreelan Creek plutons (249.1 ± 1.3 Ma and 246.3 ± 1.4 Ma respectively, Chisholm et al., 2014a). However, the new age is indistinguishable from the Koreelan Creek Granodiorite, and timing of mineralisation is not further constrained, but the new age demonstrates a temporal association between the Cullens Creek and Koreelan Creek plutons. <p>The 239.1 ± 1.2 Ma age for the Mann River Leucogranite west of Grafton is indistinguishable in age from plutons in the Dandahra Suite and supports its inclusion in this grouping. The new age also constrains the timing of the distal part of the Dalmorton Gold Field, and implies that the gold vein system postdates the Hunter-Bowen orogeny. <p>The 232.7 ± 1.0 Ma Botumburra Range Monzogranite east of Armidale is younger than most southern New England granites, but this age is very consistent with the Coastal Granite Association (CGA), and the new age, along with the previously noted petrographic similarities (Leitch and McDougall, 1979) supports incorporation of the Botumburra Range Monzogranite into the Carrai Supersuite of the CGA (Bryant, 2017).

<div>This record presents nine new zircon and titanite U–Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP) for seven samples of plutonic rocks from the Lachlan Orogen and the Cobar Basin, plus one garnet-bearing skarn vein from the Cobar region. Many of these new ages improve existing constraints on the timing of mineralisation in the Cobar Basin, as 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 Collaboration Framework (NCF) agreement. The results herein (summarised in Table 1.1) correspond to zircon and titanite U–Pb SHRIMP analysis undertaken on GSNSW Mineral Systems projects over July 2017–June 2019.</div><div><br></div><div>Our new data establish an episode of c. 427–425 Ma I-type plutonism, coeval with regional S-type granites, which marginally predated opening of the Cobar Basin. Widespread S-type and high-level I-type magmatism accompanied 423–417 Ma basin development. At least two episodes of skarn-related mineralisation are recognised in the southern Cobar Basin: c. 387 Ma (from pre-mineralisation skarn veins) at Kershaws prospect, and c. 403 Ma at the adjacent Hera mine (Fitzherbert et al., 2021).</div><div><br></div><div>Three intrusive rocks were dated at the Norma Vale prospect in the southwestern Cobar Basin, where calcic iron-copper skarn mineralisation is thought to have been caused by I-type but compositionally complex high-level intrusive rocks emplaced along a northeast-oriented fault related to the nearby Rookery Fault (Fitzherbert et al., 2017). A 423 ± 8 Ma I-type quartz diorite potentially constrains the timing of skarn mineralisation, but is indistinguishable in age from a 421.3 ± 3.0 Ma S-type cordierite-biotite granite and a 417.5 ± 3.3 Ma coarse-grained S-type granite, both from deeper in the same drillhole. These results suggest that at least some of the coeval S-type and high-level I-type magmatic activity accompanying opening of the Cobar Basin was associated with early mineralisation, although skarn-forming processes regionally are complex and episodic (Fitzherbert et al., 2021).</div><div><br></div><div>In the Cobar mining belt, our new date of 422.8 ± 2.8 Ma for I-type rhyolitic porphyry at Carissa Shaft (which is one of the southernmost high-level intrusions associated with the Perseverance and Queen Bee orebodies) is coeval with the 423.2 ± 3.5 Ma ‘Peak rhyolite’ (Black, 2007), but marginally older than the 417.6 ± 3.0 Ma Queen Bee Porphyry (Black, 2005). At Gindoono, a 423.0&nbsp;±&nbsp;2.6&nbsp;Ma unnamed dacitic porphyry intruded and hornfelsed the undated I-type Majuba Volcanics, thereby establishing a minimum age for that unit.</div><div><br></div><div>East of Cobar, the I-type Wild Wave Granodiorite intruded the Ordovician Girilambone Group, but was exhumed and eroded to form clasts within pebble conglomerates of the lowermost Cobar Basin. Its new U–Pb SHRIMP zircon age of 424.1 ± 2.8 Ma constrains the timing of I-type plutonism which marginally predated formation of the Cobar Basin. A similar zircon age of 426.7 ± 2.3 Ma was obtained from the concealed Fountaindale Granodiorite north of Condoblin, indicating that this I-type pluton is coeval with the nearby and much larger c. 427 Ma S-type Erimeran Granite. Titanite from the same sample of Fountaindale Granodiorite yielded an age of 421.6 ± 2.7 Ma, which is significantly younger than the zircon age, and is interpreted to constrain the timing of ‘deuteric’ (chlorite-albite-epidote-titanite-sericite-carbonate) alteration during post-magmatic hydrothermal activity (e.g. Blevin, 2003b).</div><div><br></div><div>A garnet-bearing skarn vein at Kershaws prospect, adjacent to the Hera orebody (Fitzherbert et al., 2021), predates the main phase of mineralisation, and yielded a titanite age of 387.2 ±&nbsp;6.2&nbsp;Ma. This indicates that the skarn-forming hydrothermal event at Kershaws prospect is significantly younger than the c. 403 Ma age for the main mineralising event at Hera mine (Fitzherbert et al., 2021).</div>

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>.

<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.