The Thomson Orogen of eastern Australia is a major component of the Tasmanides and has historically been poorly understood and overlooked for exploration due to extensive sedimentary cover including the Eromanga Basin. To further understanding and encourage exploration of this area, Geoscience Australia, the Geological Survey of Queensland and the Geological Survey of New South Wales (NSW) have undertaken a major multidisciplinary geoscientific programme in the southern Thomson Orogen (STO) as a part of the UNCOVER initiative. A major outcome of this project has been the completion of twelve stratigraphic diamond drill holes between 2016 and 2017. SHRIMP U–Pb zircon dating of magmatic and metasedimentary rocks intersected by the boreholes provide new insights into the geological evolution and mineral prospectivity of this region. Geochronology of three intrusive rocks intersected by new boreholes in the NSW part of STO have late Silurian ages of ~425 Ma (Tongo 1), ~421 Ma (Janina 1) and ~421 Ma (Congararra 1). The age of the granodiorite intersected by Tongo 1 is within uncertainty of the intrusion-related Mo-W and later Au-base metal mineralisation at the Cuttaburra and F1 prospects located ~20 km southeast of the Tongo 1 borehole. Additionally, previously unknown volcanic events have been revealed by a dacitic ignimbrite (~387 Ma) in borehole GSQ Eulo 2 (Queensland) and a rhyolite (~395 Ma) in borehole, Milcarpa 1 (NSW). Detrital zircon geochronology has also played an important role in characterising undercover units such as the Werewilka Formation and Nebine Metamorphics, interpreted from geophysical data sets. This abstract was submitted to and presented at the 2018 Australian Geoscience Council Convention (AGCC) (https://www.agcc.org.au/)

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>.

<div>Lithospheric and crustal architecture — the framework of major tectonic blocks, terranes and their boundaries — represents a fundamental first-order control on major geological systems, including the location of world-class mineral camps. Traditionally, lithospheric and crustal architecture are constrained using predominantly geophysical methods. However, Champion and Cassidy (2007) pioneered the use of regional Sm–Nd isotopic data from felsic igneous rocks to produce isotopic contour maps of the Yilgarn Craton, demonstrating the effectiveness of ‘isotopic mapping’, and the potential to map ‘time-constrained’ crustal architecture. Mole et al. (2013) demonstrated the association between lithospheric architecture and mineral systems, highlighting the potential of isotopic mapping as a greenfield area selection tool. Additional work, using Lu-Hf isotopes (Mole et al., 2014), demonstrated that the technique could constrain a range of temporal events via ‘time-slice mapping’, explaining how Ni-Cu-PGE mineralized komatiite systems migrated with the evolving lithospheric boundary of the Yilgarn Craton from 2.9 to 2.7 Ga. Similar studies have since been conducted in West Africa (Parra-Avila et al., 2018), Tibet (Hou et al., 2015), and Canada (Bjorkman, 2017; Mole et al., 2021; 2022). This work continues in Geoscience Australia’s $225 million Exploring for the Future program (2016-present). Isotopic mapping, which forms an integral part of a combined geology-geophysics-geochemistry approach, is currently being applied across southeast Australia, covering the eastern Gawler Craton, Delamerian Orogen, and western Lachlan Orogen, encompassing more than 3 Gyrs of Earth history with demonstrable potential for large mineral systems.</div><div> <b>Reference(s):</b></div><div> Bjorkman, K.E., 2017. 4D crust-mantle evolution of the Western Superior Craton: Implications for Archean granite-greenstone petrogenesis and geodynamics. University of Western Australia, PhD Thesis, 134 pp.</div><div> Champion, D.C. and Cassidy, K.F., 2007. An overview of the Yilgarn Craton and its crustal evolution. In: F.P. Bierlein and C.M. Knox-Robinson (Editors), Proceedings of Geoconferences (WA) Inc. Kalgoorlie '07 Conference. Geoscience Australia Record 2007/14, Kalgoorlie, Western Australia, pp. 8-13.</div><div> Hou, Z., Duan, L., Lu, Y., Zheng, Y., Zhu, D., Yang, Z., Yang, Z., Wang, B., Pei, Y., Zhao, Z. and McCuaig, T.C., 2015. Lithospheric architecture of the Lhasa terrane and its control on ore deposits in the Himalayan-Tibetan orogen. Economic Geology, 110(6): 1541-1575.</div><div> Mole, D.R., Fiorentini, M.L., Cassidy, K.F., Kirkland, C.L., Thebaud, N., McCuaig, T.C., Doublier, M.P., Duuring, P., Romano, S.S., Maas, R., Belousova, E.A., Barnes, S.J. and Miller, J., 2013. Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton. Geological Society, London, Special Publications, 393: pp. 23-80.</div><div> Mole, D.R., Fiorentini, M.L., Thebaud, N., Cassidy, K.F., McCuaig, T.C., Kirkland, C.L., Romano, S.S., Doublier, M.P., Belousova, E.A., Barnes, S.J. and Miller, J., 2014. Archean komatiite volcanism controlled by the evolution of early continents. Proceedings of the National Academy of Sciences, 111(28): 10083-10088.</div><div> Mole, D.R., Thurston, P.C., Marsh, J.H., Stern, R.A., Ayer, J.A., Martin, L.A.J. and Lu, Y., 2021. The formation of Neoarchean continental crust in the south-east Superior Craton by two distinct geodynamic processes. Precambrian Research, 356: 106104.</div><div> Mole, D.R., Frieman, B.M., Thurston, P.C., Marsh, J.H., Jørgensen, T.R.C., Stern, R.A., Martin, L.A.J., Lu, Y.J. and Gibson, H.L., 2022. Crustal architecture of the south-east Superior Craton and controls on mineral systems. Ore Geology Reviews, 148: 105017.</div><div> Parra-Avila, L.A., Belousova, E., Fiorentini, M.L., Eglinger, A., Block, S. and Miller, J., 2018. Zircon Hf and O-isotope constraints on the evolution of the Paleoproterozoic Baoulé-Mossi domain of the southern West African Craton. Precambrian Research, 306: 174-188.</div><div> This Abstract was submitted/presented to the Target 2023 Conference 28 July (https://6ias.org/target2023/)

<div>Archean greenstone belts are a vital window into the tectonostratigraphic processes that operated in the early Earth and the geodynamics that drove them. However, the majority of greenstone belts worldwide are highly-deformed, complicating geodynamic interpretations. The volcano-sedimentary sequence of the 2775-2690 Ma Fortescue Group is different in that it is largely undeformed, offering a unique insight into the architecture of greenstone sequences. In the Fortescue magmatic rocks, geochemical signatures that in deformed belts in the Superior or Yilgarn Cratons might have been interpreted as arc-like, are explained by contamination of rift-related mantle and plume-derived magmas with Pilbara basement crust; understanding the wider geological and structural setting allows a more complete interpretation.</div><div> However, contamination of Fortescue magmas by an enriched sub-continental mantle lithosphere (SCLM) is an alternative hypothesis to the crustal contamination model. If demonstrated, the addition of sediments and fluids to the SCLM, required to form enriched/metasomaytised SCLM, would suggest active subduction prior to the Neoarchean. To test this hypothesis, we collected Hf-O isotopic data on zircons from felsic volcanic rocks throughout the Fortescue Group; if the contamination had a subducted sedimentary component (δ18O>20‰), then the O-isotopes should record a heavy signature.</div><div> The results show that the ca. 2775 Ma Mt Roe Formation has εHfi from 0 to -5.6, and δ18OVSMOW of +4.8- +0.3‰, with the majority of values <+3‰. The ca. 2765 Ma Hardey Formation (mostly sediments) has highly unradiogenic εHfi of -5 to -9.4, and δ18O of +7.8- +6.6‰. The ca. 2730 Ma Boongal Formation displays similar values as for Mt Roe, with εHfi +1.9 to -5.5 and δ18O +3.0 to -0.6‰. The ca. 2720 Ma Tumbiana Formation shows the greatest range in εHfi from +4.9 to -4.6, with δ18O +7.1- +0.7‰, with the majority between +4.5 and +2.5‰. Data from the 2715 Ma Maddina Formation are more restricted, with εHfi between +4.0 and -0.1, and δ18O +5.0- +3.8‰. The youngest formation, the 2680 Ma Jeerinah Formation, has εHfi +2.3 to -6.2, and δ18O +5.1 to -2.1‰.</div><div> Importantly, these data provide little evidence of a cryptic enriched SCLM source in the Fortescue magmas. Furthermore, the dataset contains some of the lightest δ18O data known for Archean zircon, highlighting a ca. 100 Myr period of high-temperature magma-water interaction, with long-term continental emergence implied by the trend to meteoric δ18O compositions. The exception to this is the Hardey Formation, which may have formed via crustal anatexis in a period of reduced heat-flow between the 2775-2665 and 2730-2680 Ma events. Data from the other formations show a broad trend of increasing δ18O and εHf from 2775 to 2680 Ma. We suggest this represents the effects of progressive cratonic rifting, allowing mantle-derived magmas to reach the surface less impeded, and also a decreasing role of meteoric water in the rift zone as the sea invades. As a result, the εHf and δ18O data from the Fortescue Group represent the evolving nature of an Archean rift zone, from an emergent volcanic centre, to a submarine environment.</div><div><br></div>This Abstract was submitted/presented to the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)

<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>

<div>This Record is the fourth of a series of reports detailing the results of U–Pb dating of samples collected during investigations of the Mary Kathleen Domain and adjacent areas of the Mount Isa Inlier in 2018–19 by the Geological Survey of Queensland and co-workers (Kositcin <em>et al</em>., 2019, 2021, Bodorkos <em>et al</em>., 2020). It presents new Sensitive High Resolution Ion Microprobe (SHRIMP) U–Pb geochronological results for five samples collected from the inlier. Two of the samples are from units in the Kalkadoon–Leichhardt Domain and the remaining three from units in the adjacent Mary Kathleen Domain (Figure i). The ages of these units are poorly constrained and various ages have been proposed for most of them by different investigators.</div><div> <b>Bibliographic Reference:</b> Kositcin, N., Bultitude, R. J., Purdy, D. J. 2023. <i>Summary of results. Joint GSQ–GA Geochronology Project: Kalkadoon–Leichhardt and Mary Kathleen Domains, 2018–2020. </i>GSQ Record 2023/04, Geological Survey of Queensland. GA Record 2023/41, Geoscience Australia, Canberra. http://dx.doi.org/10.26186/148600 https://geoscience.data.qld.gov.au/data/report/cr141810

<div>The Yilgarn Craton of Western Australia represents one of the largest pieces of Precambrian crust on Earth, and a key repository of information on the Meso-Neoarchean period. Understanding the crustal, tectonic, thermal, and chemical evolution of the craton is critical in placing these events into an accurate geological context, as well as developing holistic tectonic models for the Archean Earth. In this study, we collected a large U-Pb (420 collated samples) and Hf isotopic (2163 analyses) dataset on zircon to investigate the evolution of the craton. These data provide strong evidence for a Hadean-Eoarchean origin for the Yilgarn Craton from mafic crust at ca. 4000 Ma. This ancient cratonic nucleus was subsequently rifted, expanded and reworked by successive crustal growth events at ca. 3700 Ma, ca. 3300 Ma, 3000-2900 Ma, 2825-2800 Ma, and ca. 2730-2620 Ma. The <3050 Ma crustal growth events correlate broadly with known komatiite events, and patterns of craton evolution, revealed by Hf isotope time-slice mapping, image the periodic break-up of the Yilgarn proto-continent and the formation of rift-zones between the older crustal blocks. Crustal growth and new magmatic pulses were focused into these zones and at craton margins, resulting in continent growth via internal (rift-enabled) expansion, and peripheral (crustal extraction at craton margins) magmatism. Consequently, we interpret these major geodynamic processes to be analogous to plume-lid tectonics, where the majority of tonalite-trondhjemite-granodiorite (TTG) felsic crust, and later granitic crust, was formed by reworking of hydrated mafic rocks and TTGs, respectively, via a combination of infracrustal and/or drip-tectonic settings. While this process of crust formation and evolution is not necessarily restricted to a specific geodynamic system, we find limited direct evidence that subduction-like processes formed a major tectonic component, aside from re-docking the Narryer Terrane to the craton at ca. 2740 Ma. Overall, these 'rift-expansion' and 'craton margin' crustal growth process led to an intra-cratonic architecture of younger, juvenile terranes located internal and external to older, long-lived, reworked crustal blocks. This framework provided pathways that localized later magmas and fluids, driving the exceptional mineral endowment of the Yilgarn Craton.</div> This Abstract/Poster was submitted to & presented at the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)

The nature of the substrate below the northern Lachlan Orogen and the southern Thomson Orogen is poorly understood. We investigate the nature of the mid- to lower-crust using O and Lu-Hf isotopes on zircons from magmatic rocks which intrude these regions, and focus on the 440–410 Ma time window to minimise temporal effects while focussing on spatial differences. Over the entire region, O-isotope values range from δ18O = 5.52‰ to 10.14‰, and Lu-Hf from εHft = -8.1 to +8.5. In the northern Lachlan Orogen and much of the southern Thomson Orogen, magmatic rocks with low εHft (c. -8 to -4) and elevated δ18O (c. 9 to 10‰) reflect a supracrustal source. Magmatic rocks intruding the Warratta Group in the western part of the Thomson Orogen also have low εHft (c. -10 to -6) but more subdued δ18O (c. 7‰), indicating a distinct supracrustal source in this region. In the northeast Lachlan Orogen, magmatic rocks record mixing of the supracrustal source with input from a juvenile source (εHft as high as +8.5, δ18O as low as 5.52‰), most likely of “Macquarie Arc”-type affinity. Samples in the west-southwest Thomson Orogen also record some evidence of juvenile input (εHft as high as +0.2, δ18O as low as 6.51‰), likely the Mount Wright Arc of the Koonenberry Belt. Our results show that internal isotopic variation within the Lachlan and the Thomson orogens is much greater than the difference between the two orogens. <b>Citation:</b> K. Waltenberg, S. Bodorkos, R. Armstrong & B. Fu (2018) <i>Mid- to lower-crustal architecture of the northern Lachlan and southern Thomson orogens: evidence from O–Hf isotopes, </i>Australian Journal of Earth Sciences, 65:7-8, 1009-1034, DOI: 10.1080/08120099.2018.1463928

<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).

This Record presents new U–Pb geochronological data, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), from 43 samples of predominantly igneous rocks collected from the East Riverina region of the central Lachlan Orogen, New South Wales. The results presented herein correspond to the reporting period July 2016–June 2020. This 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 agreement, to better understand the geological evolution and mineral prospectivity of the central Lachlan Orogen in southern NSW (Bodorkos et al., 2013; 2015; 2016, 2018; Waltenberg et al., 2019).