Congararra 1 borehole completion record. Southern Thomson Project. Record 2018/08 ecat Geological Survey of New South Wales Record GS2018/0204

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1 Record 2018/08 ecat Geological Survey of New South Wales Record GS2018/0204 Congararra 1 borehole completion record Southern Thomson Project I. C. Roach, K. F. Bull, D. C. Champion, C. B. Folkes, P. Gilmore, R. Hegarty, S. L. Jones, D. J. McInnes, D. B. Tilley, B. J. Williams, and S. Wong. APPLYING GEOSCIENCE TO AUSTRALIA S MOST IMPORTANT CHALLENGES

2 Congararra 1 borehole completion record Southern Thomson Project GEOSCIENCE AUSTRALIA RECORD 2018/08 GEOLOGICAL SURVEY OF NEW SOUTH WALES RECORD GS2018/0204 I. C. Roach 1, K. F. Bull 2, D. C. Champion 1, C. B. Folkes 2, P. Gilmore 2, R. Hegarty 3, S. L. Jones 1, D. J. McInnes 1, D. B. Tilley 2, B. J. Williams 2, S. Wong 1,3 1. Geoscience Australia. 2. Geological Survey of New South Wales 3. Formerly Geological Survey of New South Wales.

3 Department of Industry, Innovation and Science Minister for Resources and Northern Australia: Senator the Hon Matthew Canavan MP Secretary: Dr Heather Smith PSM Geoscience Australia Chief Executive Officer: Dr James Johnson Department of Planning and Environment, New South Wales Minister: The Hon Don Harwin MLC Secretary: Ms Carolyn McNally Geological Survey of New South Wales Executive Director: Dr Chris Yeats This paper is published with the permission of the CEO, Geoscience Australia and the Executive Director, Geological Survey of New South Wales. Commonwealth of Australia (Geoscience Australia) and State of New South Wales (Geological Survey of New South Wales) With the exception of the Commonwealth Coat of Arms and where otherwise noted, this product is provided under a Creative Commons Attribution 4.0 International Licence. ( Geoscience Australia has tried to make the information in this product as accurate as possible. However, it does not guarantee that the information is totally accurate or complete. Therefore, you should not solely rely on this information when making a commercial decision. Geoscience Australia is committed to providing web accessible content wherever possible. If you are having difficulties with accessing this document please clientservices@ga.gov.au. ISSN X (PDF) ISBN (PDF) ecat Bibliographic reference: Roach, I. C., Bull, K. F., Champion, D. C., Folkes, C. B., Gilmore, P., Hegarty, R. Jones, S. L., McInnes, D. J., Tilley, D. B., Williams, B. J. Wong, S Congararra 1 borehole completion record: Southern Thomson Project. Record 2018/08. Geoscience Australia, Canberra. Geological Survey of New South Wales Record GS2018/ Version: 1701

4 Contents 1 Introduction The Southern Thomson Project Borehole rationale, location and construction Rationale and location Borehole construction Lithology, petrography, stratigraphy, geochemistry and U-Pb isotopic age Introduction Lithology Basement rock petrography Geochemistry Stratigraphy Synthesis within the regional stratigraphic framework Borehole and drill core rock properties Introduction Rock properties measurements Results Natural gamma Magnetic susceptibility Bulk density determinations Rock properties data package HyLogger data HyLogger data acquisition and processing Results Congararra 1 mud rotary chips Congararra 1 diamond drill core Comparison with other logging HyLogger data package HyLogger data reprocessing Groundwater Acknowledgements References...29 Appendix A Borehole construction...32 Appendix B Drilling activities and consumables...34 Appendix C Petrophysical equipment details...36 C.1 Borehole wireline logging equipment...36 C.2 Hand-held magnetic susceptibility logging equipment...36 C.3 Analytical balance equipment (density determination)...36 Appendix D Petrophysical data acquisition and processing...37 D.1 Data acquisition and processing...37 D.2 Equipment calibration...37 D.3 Data processing...38 Congararra 1 borehole completion record iii

5 Appendix E Lithological and stratigraphic log...39 Appendix F Deviation survey...40 Appendix G Whole rock geochemistry...41 Appendix H Metallogenic and Igneous classifications...44 Appendix I Borehole log...47 iv Congararra 1 borehole completion record

6 Figures Figure 1.1: Location of the Thomson Orogen in eastern Australia. The red box encompasses the Southern Thomson Project area Figure 1.2: Location map of all boreholes drilled as part of the Southern Thomson Project. Background: TOPO 250K topographic map mosaic, Geoscience Australia Figure 2.1: Location map of the Congararra 1 borehole with local waterbores. Background: TOPO 250K mosaic of Australia, Geoscience Australia Figure 2.2: Location map showing the Congararra 1 borehole and solid geological basement interpretation from Purdy et al. (2014) and Purdy et al. (2018), over a first vertical derivative of total magnetic intensity (1VD TMI) image of the Magnetic Map of Australia Figure 2.3: Location map of the Congararra 1 borehole overlain on AEM conductivity depth sections for selected flight lines. Background image: ENNGONIA 1:250,000 geological map sheet (Fitzpatrick et al., 1965). Airborne electromagnetic conductivity depth sections are shown in a 2D representation by rotating them 90 from vertical to lie in the plane of the map view. Flight line 6040 lies exactly over the top of the Congararra 1 borehole site, and flight line 6110 passes ~600 m to the southeast of the borehole site at its closest. Dark blue colours in the conductivity depth sections indicate the presence of electrically resistive basement rocks covered by electrically conductive sedimentary rocks of the Eromanga Basin in red and yellow colours. More information regarding the acquisition, processing and interpretation of AEM data in the Project area is available in Roach (2015) and Brodie et al. (in prep)... 6 Figure 2.4: The Congararra 1 borehole site prior to drilling, looking west Figure 2.5: Drilling operations at Congararra 1 showing the site layout, looking southwest Figure 2.6: Image showing the partial rehabilitation of the work area and temporary fencing out of mud sumps at Congararra 1, looking northwest. The temporary fencing around the sumps was replaced by the landholder until such time as the sumps dry out before backfilling with the original soil. The articulated loader is using a stick rake to drag sand across the site, removing wheel ruts left by heavy equipment and leaving furrows to catch seeds and rainfall. Dead vegetation from the site is scattered across the site by hand to help reduce erosion and provide habitat for regrowth Figure 3.1: Mud rotary chip sample layout at the Congararra 1 borehole site. Samples are laid out on black plastic starting in the top left corner, moving right in runs of 10 m, with the sample from the deepest part of the borehole in the foreground at bottom right. Note the colour change in chips from the surface weathering zone (back) to unweathered Eromanga Basin rocks and basement chips in the foreground. Image: Sebastian Wong GSNSW Figure 3.2: Congararra 1 lithological and stratigraphic log. Lithology is summarised from the detailed lithological log attached in Appendix E Figure 3.3: Dry (above) and wet (below) field photos of typical diamond drill core from Congararra Figure 3.4: Representative thin-section photomicrographs from the Congararra 1 borehole. The top left image is from ~90.2 m DL and the other images are from ~106.6 m DL Congararra 1 borehole completion record v

7 Figure 3.5: Geochemical discrimination plots for selected igneous rocks sampled as part of the Southern Thomson Project. Analyses include samples from Tongo 1 (Roach et al., 2018a), Congararra 1, Congararra 2 (Roach et al., 2018c), Janina 1 (Roach et al., 2018d) and Milcarpa 1 (Roach et al., 2018b). A: Plutonic rock classification of Debon and Le Fort (1983). X and Y axes correspond to proportions of quartz (Q) and plagioclase (P). B: K 2 O versus SiO 2 classification plot. Boundary fields are from Le Maitre (2002). C: A plot of Fe 2 O 3 /FeO versus total Fe as FeO* (wt.%), after Champion and Heinemann (1994), showing the fields for strongly reduced, reduced, oxidised and strongly oxidised. Samples from New South Wales drill holes are also shown, which range from strongly reduced and reduced (Congararra 1 & 2, Janina 1) to oxidised (Milcarpa 1, Tongo 1). D: Rb-Ba-Sr triangular plot from El Bouseily and El Sokkary (1975) showing the fields for normal and fractionated granites. Samples show they are not significantly fractionated. E: Plot of Rb/Sr versus Fe 2 O 3 /FeO, from Blevin et al. (1996), with the field of Intrusion-related gold deposits (IRGD) from Blevin (2004)...15 Figure 4.1: Lithology, stratigraphy, rock properties data and borehole construction for Congararra 1. The legend for lithology types is the same as in Figure Figure 5.1: Mineral spectra summary plot of Congararra 1 mud rotary chips Figure 5.2: Mineral spectra summary plot of Congararra 1 diamond drill core Figure 5.3A: Comparison between spectral mineralogy, interpreted stratigraphy and borehole rock properties data from Congararra 1. The spectral mineralogy legends in the log refer to the mud rotary drilled portion of the borehole <69 m TVD, and in the lower part to the diamond drilled portion to EOH Figure 8.1: Congararra 1 borehole construction vi Congararra 1 borehole completion record

8 Tables Table 2.1: Details for the Congararra 1 borehole Table 3.1: Whole-rock geochemical petrographic and metallogenic indicators and SHRIMP U- Pb age for Congararra 1 basement dyke rocks Table 3.2: Interpreted stratigraphy of the Congararra 1 borehole Table 4.1: Congararra 1 natural gamma stratigraphic interval statistics Table 4.2: Congararra 1 magnetic susceptibility stratigraphic interval magnetic susceptibility statistics Table 4.3: Bulk density measurements on diamond drill core from Congararra Table 6.1: Local waterbores within the Congararra 1 vicinity highlighting the overall sub-artesian water pressures present in the area. Refer to Figure 2.2 for locations Table 8.1: Congararra 1 drilling times and production rates Table 8.2: Congararra 1 drilling consumables used Table 8.3: Borehole wireline data acquisition steps in Congararra Table 8.4: Deviation survey data for Congararra Table 8.5: Whole-rock major element geochemical data for Congararra Table 8.6: Whole-rock trace element geochemical data for Congararra Congararra 1 borehole completion record vii

9 1 Introduction 1.1 The Southern Thomson Project The Thomson Orogen is a major component of the Paleozoic Tasmanides of eastern Australia that extends through large portions of central and southwest Queensland and northwest New South Wales (Figure 1.1). Much of the Thomson Orogen is buried under younger sedimentary basins (some up to several kilometres thick) and regolith cover, making it one of the most poorly understood elements of Australia s geology. As a result, the mineral potential of the region is also poorly defined. The Southern Thomson Project (the Project) is a collaborative investigation between the Commonwealth of Australia (Geoscience Australia GA) and its partners the State of New South Wales (Department of Planning and Environment, Geological Survey of New South Wales GSNSW) and the State of Queensland (Department of Natural Resources, Mines and Energy, Geological Survey of Queensland GSQ). Figure 1.1: Location of the Thomson Orogen in eastern Australia. The red box encompasses the Southern Thomson Project area. The Project aims to better understand the geological character and mineral potential of the southern Thomson Orogen region, focusing on the border between New South Wales and Queensland, by acquiring and interpreting multi-disciplinary geophysical, geochemical, geological and geochronological data. The primary intended impact of this work is to provide the mineral exploration Congararra 1 borehole completion record 1

10 industry with pre-competitive data and knowledge that reduces risk and encourages mineral exploration in the region. The pre-competitive data collection culminated in a drilling program of 12 boreholes within the project area of New South Wales and Queensland (Figure 1.2), targeting strategic basement rocks that will improve the understanding of the mineral potential of the southern Thomson Orogen and its geodynamic setting within the Tasmanides of eastern Australia. Figure 1.2: Location map of all boreholes drilled as part of the Southern Thomson Project. Background: TOPO 250K topographic map mosaic, Geoscience Australia. 2 Congararra 1 borehole completion record

11 2 Borehole rationale, location and construction I. C. Roach, R. Hegarty and C. B. Folkes 2.1 Rationale and location The Congararra 1 borehole was drilled approximately 70 km NNW of Bourke, NSW (figures 1.2, 2.1, Table 2.1). The borehole was designed to test aeromagnetic anomalies in the basement rocks (Figure 2.2) and to test the electrical conductivity properties of cover and basement rocks to validate airborne electromagnetic (AEM) data (Figure 2.3). The Congararra 1 borehole was drilled as an inclined borehole to recover structural information from the oriented diamond drill core. Drilled lengths (DL) of features in the borehole are converted to True Vertical Depth (TVD) in the text and tables below unless otherwise labelled, and all measurements are relative to ground level. Table 2.1: Details for the Congararra 1 borehole. Hole ID Congararra 1 Site ID* Harriet Park 2* Contractor Drilling rig Landholder DRC Drilling Pty Ltd Sandvik DE880 Title EL 8444 Status Congararra Station Closed, cemented to surface, cement cap installed, site remediation earthworks were not completed at the time of publication Location Longitude (GDA94): Latitude (GDA94): Easting (MGAZ55S): m Northing (MGAZ55S: m Elevation (ellipsoidal): 121 m Drilled length Casing Casing cut-off depth Grouting m m DL steel mm OD, removed before borehole abandonment m DL (end of hole - EOH) HQ3 open hole 0.5 m below surface Cement, from EOH to surface Mud rotary drilled length m DL (69.0 m DL) Diamond drilled length Commencement date Completion date Deviation m DL (44.0 m DL) Drilling rig mast oriented -80 /180 magnetic Deviation survey date (Appendix F) GA Boreholes ENO *Project internal reference to pre-drilling geophysics site. Congararra 1 borehole completion record 3

12 Figure 2.1: Location map of the Congararra 1 borehole with local waterbores. Background: TOPO 250K mosaic of Australia, Geoscience Australia. 4 Congararra 1 borehole completion record

13 Figure 2.2: Location map showing the Congararra 1 borehole and solid geological basement interpretation from Purdy et al. (2014) and Purdy et al. (2018), over a first vertical derivative of total magnetic intensity (1VD TMI) image of the Magnetic Map of Australia Congararra 1 borehole completion record 5

14 Figure 2.3: Location map of the Congararra 1 borehole overlain on AEM conductivity depth sections for selected flight lines. Background image: ENNGONIA 1:250,000 geological map sheet (Fitzpatrick et al., 1965). Airborne electromagnetic conductivity depth sections are shown in a 2D representation by rotating them 90 from vertical to lie in the plane of the map view. Flight line 6040 lies exactly over the top of the Congararra 1 borehole site, and flight line 6110 passes ~600 m to the southeast of the borehole site at its closest. Dark blue colours in the conductivity depth sections indicate the presence of electrically resistive basement rocks covered by electrically conductive sedimentary rocks of the Eromanga Basin in red and yellow colours. More information regarding the acquisition, processing and interpretation of AEM data in the Project area is available in Roach (2015) and Brodie et al. (in prep) 6 Congararra 1 borehole completion record

15 2.2 Borehole construction The Project team at this site included scientists from GA and the GSNSW, a licensed water bore driller, and the contractor s drilling team. The borehole was drilled as an inclined mud rotary borehole using two small inter-connected sumps (approximately 3 x 5 x 1.5 m) to catch mud rotary drill cuttings to 69 m DL before switching to an inclined diamond drilling operation, extending the borehole to m DL using a third small sump (approximately 2 x 4 x 1.5 m) to catch cuttings in the diamond drilling fluids. Before commencement the Project team reviewed the standing water levels (SWL) in the area to assess the likelihood of artesian groundwater conditions within the borehole by assessing bore cards for local water bores (Figure 2.1) available from the NSW Department of Primary Industries Office of Water ( Local waterbores were assessed as being strongly artesian to the east of the site, where numerous mound springs also occur. Artesian water also occurs in waterbore GW010667, ~3.6 km west of the Congararra 1 borehole site; however the SWL at this site is only 1.5 m. The Project team also assessed the cover thickness in order to assess the likelihood of pressurised aquifers occurring at the site using airborne electromagnetic (AEM) data (Figure 2.3), which was flown specifically over the site for cover thickness mapping and drilling risk reduction purposes in 2016 (Brodie et al., in prep). The results from the AEM survey indicate that the Congararra 1 borehole site is located over relatively thin cover (~50 m) and that the likelihood of encountering artesian groundwater in one of the major regional aquifers was minor to non-existent. Using this pre-drilling knowledge, the Project team worked to ensure that the drilling fluid was correctly weighted before any aquifers were likely to be encountered to prevent the accidental escape of artesian groundwater. The borehole was fully cased with steel casing through the entire cover sequence into competent basement rock before commencement of diamond drilling operations. This was to prevent swelling clays in the Eromanga Basin sequence from closing the borehole, to prevent accidental groundwater escape, to prevent groundwater mixing between aquifers and to prevent drilling fluids from contaminating groundwater in accordance with the requirements of the Minimum Construction Requirements for Water Bores In Australia (National Uniform Drillers Licensing Committee, 2011). More information regarding borehole construction and drilling consumables is available in Appendix A and Appendix B and images of the site before, during and after drilling are included in Figures 2.4 to 2.6. Congararra 1 borehole completion record 7

16 Figure 2.4: The Congararra 1 borehole site prior to drilling, looking west. Figure 2.5: Drilling operations at Congararra 1 showing the site layout, looking southwest. 8 Congararra 1 borehole completion record

17 Figure 2.6: Image showing the partial rehabilitation of the work area and temporary fencing out of mud sumps at Congararra 1, looking northwest. The temporary fencing around the sumps was replaced by the landholder until such time as the sumps dry out before backfilling with the original soil. The articulated loader is using a stick rake to drag sand across the site, removing wheel ruts left by heavy equipment and leaving furrows to catch seeds and rainfall. Dead vegetation from the site is scattered across the site by hand to help reduce erosion and provide habitat for regrowth. Congararra 1 borehole completion record 9

18 3 Lithology, petrography, stratigraphy, geochemistry and U-Pb isotopic age I. C. Roach, S. Wong, B. Williams, K. Bull, C. B. Folkes, P. Gilmore and D. C. Champion 3.1 Introduction Cuttings and drill core from Congararra 1 were logged on site by GSNSW and GA geologists. Cuttings were collected from the mud rotary-drilled cover sequence and the top of basement at 1 m intervals to 69.0 m DL, after which diamond coring commenced through to m DL. The sampling of some intervals was incomplete due to problems with the drilling fluid mixture; however the overall cutting quality and volume was high. Most 1 m intervals were represented by an amount of cuttings sufficient to fill a chip tray and a 250 ml sample vial for future analysis. Cuttings were laid out to partially dewater (Figure 3.1) before washing, lithological logging, sampling and analysis with a hand-held magnetic susceptibility meter. Key parameters of grainsize, colour and organic matter content, and any other major textural changes, were recorded. The basement diamond drill core interval (69.0 m DL to m DL) was also logged and photographed on site. Figure 3.1: Mud rotary chip sample layout at the Congararra 1 borehole site. Samples are laid out on black plastic starting in the top left corner, moving right in runs of 10 m, with the sample from the deepest part of the borehole in the foreground at bottom right. Note the colour change in chips from the surface weathering zone (back) to unweathered Eromanga Basin rocks and basement chips in the foreground. Image: Sebastian Wong GSNSW. 10 Congararra 1 borehole completion record

19 3.2 Lithology Congararra 1 penetrated ~46 m DL of cover sediments and sedimentary rocks before entering metamorphic rocks of the basement. Lithological types observed in the hole are described below and in Figure 3.2. Regolith at Congararra 1 consists of ~3 m of light brown-grey to red-brown alluvial sediment which consists of well sorted, variably ferruginised clay to very fine-grained sand. Below this a short interval (3 m DL to 4 m DL) consists of light grey, poorly sorted clay to quartzose granules with ferruginous mottles. Below this a prominent silcrete band was encountered from 4 m DL to 8 m DL, consisting white-grey silcrete consisting of fine-grained sand which is partly ferruginised in the top ~1 m. Silcreted sediments are common until ~24 m DL, consisting of quartz arenite (8 m DL to 10 m DL), lithic sandstone with common coarse lithic fragments (10 m DL to 11 m DL), arenite consisting of very coarse-grained sandstone with 25% lithic fragments (13 m DL to 15 m DL) sandy siltstone (15 m DL to 17 m DL), silcrete consisting of silcreted siltstone and fine- to medium-grained sandstone with lithic fragments (17 m DL to 20 m DL), silty sand with silcrete chips (20 m DL to 22 m DL) and arenite consisting of poorly sorted lithic sandstone with silcrete chips and yellow clay (22 m DL to 24 m DL). Below this interval silcrete was not found, but rocks become micaceous, consisting of green-grey sandy siltstone (24 m DL to 25 m DL), green-grey siltstone (25 m DL to 27 m DL), green-grey sandy siltstone (27 m DL to 31 m DL), and dark grey sandy siltstone (31 m DL to 36 m DL). Below this the borehole passed through a quartz arenite consisting of sub-rounded fine-grained sand, and medium to coarse-grained lithic fragments and quartz (36 m DL to 39 m DL), dark brown micaceous sandy siltstone (39 m DL to 41 m DL) and grey-green-beige gravelly silty sandstone before reaching the base of surface weathering estimated to occur between 42 m DL and 44 m DL. Sedimentary rocks below the base of surface weathering consist of a thin unit of grey gravelly sand consisting of lithics and rounded quartz grains between 42 m DL and 46 m DL. Saprolitic basement rocks are interpreted to occur from 46 m DL to 54 m DL consisting of coarsegrained, gravelly, silty sandstone with lithics and rounded quartz grains before entering soft basement rocks, with mud rotary refusal at 69 m DL. Diamond drill core of the basement reveals soft, schistose rocks consisting of angular quartz, cream-coloured feldspar with green alteration rims and foliated more mafic schistose lithic fragments (Figure 3.3). The base of palaeoweathering is interpreted to occur at ~76 m DL, where rocks become more competent. Congararra 1 borehole completion record 11

20 Figure 3.2: Congararra 1 lithological and stratigraphic log. Lithology is summarised from the detailed lithological log attached in Appendix E. 12 Congararra 1 borehole completion record

21 Figure 3.3: Dry (above) and wet (below) field photos of typical diamond drill core from Congararra Basement rock petrography Two representative thin-sections of basement rocks were taken at downhole depths of 90.2 m DL and m DL. The lithology is described as quartz-cordierite-sillimanite-biotite paragneiss. The foliation within the basement rocks is predominantly caused by alignment of sillimanite (in fibrolite form), commonly found within cordierite crystals (e.g. Figure 3.4). Cordierite is variably retrogressing to muscovite along the margins of interstitial crystals but also almost entirely replaced by muscovite in other crystals (Figure 3.4). Rutile crystals are present within and around biotite crystals (Figure 3.4) and often replaced by ilmenite and biotite. There are also large stubby zircon and apatite crystals (likely to be detrital) and some possible tourmaline crystals present in the mineral assemblage. There is little to no feldspar observed in the thin-sections. These basement rocks are interpreted to have originally been aluminium-rich source rocks (pelite) that underwent high temperature-low pressure metamorphism in order to partially melt the source rocks and produce the observed mineral assemblage. To produce this mineral assemblage, conditions Congararra 1 borehole completion record 13

22 would have been ~750 C and <3 kbars; the absence of garnet limits the temperature to <800 C and the growth of cordierite indicates low pressures (White et al., 2014). The stability field of this mineral assemblage suggests metamorphism to amphibolite facies. The presence of cordierite crystals growing around earlier formed sillimanite also indicates a possible contact metamorphic event. Figure 3.4: Representative thin-section photomicrographs from the Congararra 1 borehole. The top left image is from ~90.2 m DL and the other images are from ~106.6 m DL. Two dykes of grey medium- to coarse-grained muscovite granodiorite cut the metasedimentary rocks. The granodiorite forms one 20 cm thick, concordant vein in the paragneiss, and is readily identifiable by the change in grain size and composition from plagioclase-rich granodiorite to plagioclase-poor mica-quartz-rich metasediment. Plagioclase in the granodiorite is abundant. It is moderately zoned with marked, locally patchy zoned, cores. Muscovite is in part restitic or xenocrystic, identified by the presence of fibrolite inclusions. The granodiorite also contains irregular metasedimentary clots locally to 7%. The granodiorite has a granoblastic texture with irregular to lobed grain boundaries. Quartz grains are also strained with undulose extinction and sub-grain development. 3.4 Geochemistry The granodiorite dyke rock from Congararra 1 was analysed for whole-rock major and trace element geochemistry at the Bureau Veritas Laboratories in Perth, Western Australia. A summary of whole rock geochemistry is presented in Table 3.1. Complete geochemical analyses are presented in Appendix G and metallogenic and igneous classifications used are discussed in Appendix H. The igneous dyke rock from Congararra 1 was assessed as being reduced, unfractionated granodiorite with affinities for W mineralisation, and perhaps intrusion-related Au, based on the classification scheme of Blevin et al. (1996) and Blevin (2004) (Figure 3.5). 14 Congararra 1 borehole completion record

23 Figure 3.5: Geochemical discrimination plots for selected igneous rocks sampled as part of the Southern Thomson Project. Analyses include samples from Tongo 1 (Roach et al., 2018a), Congararra 1, Congararra 2 (Roach et al., 2018c), Janina 1 (Roach et al., 2018d) and Milcarpa 1 (Roach et al., 2018b). A: Plutonic rock classification of Debon and Le Fort (1983). X and Y axes correspond to proportions of quartz (Q) and plagioclase (P). B: K 2O versus SiO 2 classification plot. Boundary fields are from Le Maitre (2002). C: A plot of Fe 2O 3/FeO versus total Fe as FeO* (wt.%), after Champion and Heinemann (1994), showing the fields for strongly reduced, reduced, oxidised and strongly oxidised. Samples from New South Wales drill holes are also shown, which range from strongly reduced and reduced (Congararra 1 & 2, Janina 1) to oxidised (Milcarpa 1, Tongo 1). D: Rb-Ba-Sr triangular plot from El Bouseily and El Sokkary (1975) showing the fields for normal and fractionated granites. Samples show they are not significantly fractionated. E: Plot of Rb/Sr versus Fe 2O 3/FeO, from Blevin et al. (1996), with the field of Intrusion-related gold deposits (IRGD) from Blevin (2004). Congararra 1 borehole completion record 15

24 Table 3.1: Whole-rock geochemical petrographic and metallogenic indicators and SHRIMP U-Pb age for Congararra 1 basement dyke rocks. Classification (Figure 3.5A): Granodiorite K 2O content (Figure 3.5B) Medium-high; Na 2O/K 2O <1.0 A/CNK: Peraluminous (1.2) Fractionation: K/Rb: 206 Rb/Sr: 0.57 Ba-Rb-Sr: unfractionated Eu/Eu*: Redox (Figure 3.5C): Redox-Evolution plot (Blevin; Figure 3.5D): Large positive anomalies (2.6), suggesting cumulate or xenocrystic/restitic plagioclase Fe 2O 3/FeO: 0.33: reduced Reduced-unfractionated Adakite signature: No; HREE positive slope (Gd/Yb)N 0.55; low Sr/Y: 7.3 Classification: Anomalous elements: Whole Rock Aqua Regia Prospectivity (Figure 3.5E): Magnetic medium-high-k, S-type Elevated Sn (6.6 ppm) and Ge (1.8 ppm), slightly elevated Ag (0.10 ppm), otherwise no obvious anomalies. Slightly elevated Au (2.5 ppb) and Bi (0.32 ppm), other elements close to detection level. Based on evolution redox plot falls into the W field and possibly the IRG field 3.5 Stratigraphy The stratigraphy in the Congararra 1 borehole (Table 3.2) is interpreted based on geological mapping on the ENNGONIA 1:250,000 (Fitzpatrick et al., 1965), YANTABULLA 1:250,000 (Wallis and McEwan, 1962) and the EULO 1:250,000 (Senior et al., 1969) geological maps, interpretations from regional water bores and regional stratigraphic drill holes described by Hawke and Cramsie (1984) and Cook et al. (2013). The upper unit encountered between the surface and ~4 m in the borehole is described by Fitzpatrick et al. (1965) as Qrs, black soil, silt, sand, secondary travertine, kopi with minor claypans. However, we have labelled this as Qa, which is consistent with the setting of the borehole within the upper reaches of a distributary drainage system which leads to the Warrego River. This unit does not belong strictly to a recognised geological province, but is part of the Murray-Darling hydrogeological basin. Below this lies a m TVD thickness of interbedded claystone, siltstone, sandstone and arkose, the top portion of which is indurated by silcrete to a depth of ~23.53 m TVD, and is weathered to ~42 m TVD, before becoming fresh, grey-coloured rocks to the basement-cover interface at m TVD. This unit is mapped as the Rolling Downs Group on the ENGONNIA 1:250,000 geological map sheet (Fitzpatrick et al., 1965), and may represent source-proximal Wallumbilla Formation in keeping with the understanding from Hawke and Cramsie (1984) regarding the distribution of the Wallumbilla Formation in northern NSW and the absence of the Winton Formation in this area. Proximity to basement was indicated by a sharp increase in the abundance of coarse, angular quartz grains, biotite flakes, feldspars and schistose lithic fragments in cuttings below ~46 m DL. Basement rocks in Congararra 1 are interpreted to occur from m TVD to the EOH. These consist of soft, micaceous, quartzose metamorphic rocks which occasionally have a schistose fabric but otherwise appear as a gneissose melange (Figure 3.3). This disrupted fabric is attributed to the 16 Congararra 1 borehole completion record

25 proximity of the borehole to the Culgoa Fault to the southeast, which is a complex fault which drags the local granite and its country rocks along dextral splays (Doublier et al., in review). Table 3.2: Interpreted stratigraphy of the Congararra 1 borehole. Province No province Eromanga Basin Stratigraphic unit Top depth (m TVD) Quaternary alluvium Rolling Downs Group Bottom depth (m TVD) True thickness (m) Thomson Orogen Basement EOH Synthesis within the regional stratigraphic framework The mineral assemblage, interpreted metamorphic conditions and location of these basement rocks constitute an interesting history. In order to melt a pelite source to produce the observed metamorphic assemblage high temperature-low pressure conditions (calculated ~750 C and <3 kbars) are required. These are essentially the conditions of high-level (shallow) granite. The location of this borehole is consistent with metamorphic rocks observed in the interpreted basement lithology of Purdy et al. (2018). The currently mapped lithology is the Twin Tanks Metamorphics ( mica schist, gneiss and minor granite ), which provides a reasonable description of the basement rocks intersected by the Congararra 1 borehole. The currently mapped Hungerford Granite and/or the intermediate igneous rocks defined by a magnetically-high zone (Purdy et al., 2018) would appear to be intrinsically related to the metamorphic basement rocks observed in the Congararra 1 borehole. These igneous rocks could either be the melted products of the source rocks, part of the source of the meta-pelites in Congararra 1, the heat source that drove the melting itself, and/or contact metamorphism, or some combination of these factors. Indeed the location and basement rocks of the nearby Congararra 2 borehole (Roach et al., 2018c) indicate a granitic rock intimately related to the metamorphic basement rocks in the Congararra 1 borehole. The proximity of this borehole to the Culgoa Lineament and splays branching off from this may also have influenced the generation and disrupted fabric of these basement rocks. The two samples selected for geochemistry (the host metasedimentary rock and a granitic dyke) provide interesting results. Preliminary investigation shows that the granodiorite dyke has a markedly different character to both the granite sampled in the Congararra 2 borehole (e.g. Figure 3.5) and other nearby granitic rocks (e.g. the Hungerford, Brewarrina and Cuttaburra granites). Interestingly, the geochemistry of the Congararra 2 granite (and the Janina 1 granite; Roach et al., 2018d) appears to have an intermediate composition between the Congararra 1 granitic dyke and metasedimentary rock (i.e. figures 3.5B-E) suggesting it could be have been generated from a mixture of these two lithologies analysed at Congararra 1. Geochronological (Cross et al., in prep) and further geochemical and analyses will be forthcoming and will better help to place the lithologies sampled with this borehole in a regional context. Congararra 1 borehole completion record 17

26 4 Borehole and drill core rock properties I. C. Roach, S. Wong, B. J. Williams and S. L. Jones 4.1 Introduction Rock properties data provide the petrophysical link between observed geophysics and under-cover geology. Rock properties data may be used to help constrain models and inversions of potential fields (magnetic, gravity) geophysical data, resulting in more accurate predictions of geology from geophysics. Electrical conductivity rock properties data can also be used to constrain inversions of airborne electromagnetic (AEM) data for regional geological and groundwater resources mapping. 4.2 Rock properties measurements Rock properties measurements were performed in situ using borehole wireline logging tools, using hand-held equipment on mud rotary drill chips and diamond drill core in the field, and using hand-held and laboratory equipment in the GSNSW core repository at Londonderry, New South Wales, and at the Coffey Services Australia Pty Ltd laboratory in Fyshwick, Australian Capital Territory. Rock properties measurements include: Natural gamma (borehole wireline) Magnetic susceptibility (borehole wireline on uncased basement rocks and hand-held on mud rotary drill chips and diamond drill core) Bulk density (drill core only). Borehole wireline logging was performed in stages, where possible, between drilling and subsequent borehole casing installation owing to the necessities of safely drilling and casing boreholes through the GAB, and preventing the uncontrolled escape of artesian groundwater. Every attempt was made to obtain borehole wireline rock properties measurements from open, uncased sections of each borehole. Details of the equipment used are provided in Appendix C. No in situ density measurements were obtained. Data acquisition, processing and quality control details are included in Appendix D and an enlargedscale graphic log is included in Appendix I. 4.3 Results Natural gamma Natural gamma data were obtained along the full length of the borehole (Figure 4.1), from uncased sections in stages as they became available, and through casing at the completion of drilling. The statistics included in Table 4.1 are taken from a composite of data from the uncased borehole. Natural 18 Congararra 1 borehole completion record

27 gamma data are processed according to the description in Appendix D and are presented using American Petroleum Institute (API) units. Natural gamma data are subdued in the Quaternary alluvial cover at the site reflecting the quartz-rich nature of the cover sediments. From ~10 m DL natural gamma emissions jump suddenly, most likely reflecting a mineralogical change between a leached, well developed silcrete and more labile, clay-rich sedimentary rocks below this position. Natural gamma emission slowly increases to the base of surface weathering, where there is no leaching due to weathering, but minor variations reflect mineralogical changes in the Wallumbilla Formation, from clay-rich to quartz-rich. Basement rocks display minor variations in natural gamma emission that can be attributed to leaching due to palaeoweathering, and slight mineralogical variation in the rocks. There are no string departures in emissions in the basement rocks presumably due to the relatively homogeneous nature of the rocks. There appears to be no correlation between natural gamma emission and magnetic susceptibility. Table 4.1: Congararra 1 natural gamma stratigraphic interval statistics. Strat unit Minimum (API) Maximum (API) Average (API) SD (API) Quaternary Wallumbilla Formation Basement Magnetic susceptibility Magnetic susceptibility data were obtained using a handheld magnetic susceptibility meter (see Appendix C) from mud rotary chips and diamond drill core from the Congararra 1 borehole. A borehole magnetic susceptibility tool was used to cross-check the data and ensure that there was no metal particle contamination affecting the results, but the borehole wireline magnetic susceptibility data are not included here because they were deemed to be too noisy, and were incomplete due to steel borehole casing. The Congararra 1 borehole was situated to sample magnetic rocks in the basement associated with the Culgoa Fault system (Figure 2.2). Magnetic susceptibility measurements indicate that the cover sediments and sedimentary rocks of the Quaternary and Mesozoic sequence are relatively nonmagnetic. Basement rocks can have elevated magnetic susceptibilities, >400 x 10-5 SI units, and are responsible for the magnetic anomaly at the site (Figure 2.2). Table 4.2: Congararra 1 magnetic susceptibility stratigraphic interval magnetic susceptibility statistics. Minimum (SI x 10-5 ) Maximum (SI x 10-5 ) Average (SI x 10-5 ) SD (SI x 10-5 ) Quaternary Wallumbilla Formation Basement Congararra 1 borehole completion record 19

28 Figure 4.1: Lithology, stratigraphy, rock properties data and borehole construction for Congararra 1. The legend for lithology types is the same as in Figure Congararra 1 borehole completion record

29 4.3.3 Bulk density determinations Samples of fresh rock from the Congararra 1 diamond drill core were submitted to the Coffey Services Australia Pty Ltd laboratory in Fyshwick, Australian Capital Territory, for determination of dry bulk density, saturated bulk density, grain density and apparent porosity according to Australian Standard AS Dry bulk density, saturated wet bulk density and grain bulk density of the rock is almost uniformly 2.78 g/cm 3 in the fresh rock and porosity is effectively zero. A sample from between 81.0 m DL and 81.2 m DL, closer to the surface, has slightly lower density (2.74 g/cm 3 dry bulk density) and 0.17% porosity, indicating that this sample may still be in the palaeoweathering profile developed on the basement rocks and may be slightly altered. Table 4.3: Bulk density measurements on diamond drill core from Congararra 1. From (m DL) To (m DL) n samples Mean dry bulk density (g/cm 3 ) Mean saturated bulk density (g/cm 3 ) Mean grain density (g/cm 3 ) Mean apparent porosity (%) ± ± ± ± Error is calculated as 1 standard deviation of the sample population 4.4 Rock properties data package Rock properties data for Congararra 1 are compiled as a Log ASCII Standard (LAS) file available for free download from the GA website and through the Rock Properties Explorer discovery tool ( Rock properties data are also include in a Web Mapping Service (WMS) and Web Feature Service (WFS) from GA ( Congararra 1 borehole completion record 21

30 5 HyLogger data D. B. Tilley and I. C. Roach 5.1 HyLogger data acquisition and processing Diamond drill cores and mud rotary chips were spectrally scanned using the CSIRO-developed HyLogger system at NSW Planning and Environment s HyLogger facility in the W.B. Clarke Geoscience Centre, Londonderry, NSW. The resultant spectral data were analysed using The Spectral Geologist (TSG) software, also developed by the CSIRO. This instrument measures spectra in three different wavelength bands (Mason and Huntington, 2012): the visible-near infrared (VNIR) between 380 and 1072 nm the short-wave infrared (SWIR) between 1072 and 2500 nm the thermal infrared (TIR) from 6000 and 14,500 nm. The HyLogger instrument collects spectral data and imagery of geological materials on a systematic basis. The near-continuous nature and abundance of the spectral data collected provides ideal datasets which can be processed to identify systematic changes in the overall mineral assemblage along diamond drill cores and chip trays. This can highlight shifts in the nature of individual mineral species present (particularly chlorite and white mica), and identify changes in the relative abundance of specific minerals. Prior to scanning, the diamond drill core was cleaned with a vacuum cleaner and moistened cloth to remove dust, dirt and in-tray debris. Disjointed core pieces were realigned and reconnected within sections of a tray to make a continuous core stick. Following this, the core was allowed to dry to reduce H 2 O spectral interference prior to scanning. In contrast, the only preparation done on the chips was that they were allowed to dry within their trays for a few days in open air. A number of specialised scalars were used for inferring changes in the composition of white mica and chlorite and for estimating their relative abundances in core and chips. For white mica composition and relative abundance The Spectral Assistant (TSA ) batch scalars White Mica Wavelength v1.2 and White Mica Intensity v1.2 were used. These scalars are based on the wavelength and depth of the Al-OH absorption feature in the short-wave infrared (SWIR) spectrum. It has been noted by Pontual et al. (2008) that the absorption minimum ranges from 2184 nm for paragonite (Na-sericite), to 2202 nm for muscovite ( normal potassic compositions) and 2225 nm for phengite compositions (Mg-Fe substituted sericites). Also, the scalar s batch script specifies that any identification of montmorillonite by TSA will provide a null result, whilst samples classified by TSA as bearing highly crystalline and/or illitic white micas are included in the determinations. The highly crystalline white micas include muscovite, phengite and paragonite whilst the illitic white micas include illite, phengitic illite and paragonitic illite. The depth of the feature provides an estimation of the relative abundance of white mica within core and chips. The inferred composition and relative abundance of chlorite group minerals were determined using the following TSG Feature Extraction (FeatEx) scalars: chlorite composition: FeatEx Wvl, 2253 nm ± 10 nm chlorite relative abundance: FeatEx Depth, 2253 nm ± 10 nm. 22 Congararra 1 borehole completion record

31 These scalars were used to determine the wavelength and depth of the Fe-OH absorption feature in the SWIR spectrum. The chlorite Mg-OH feature can be affected by the presence of carbonate, which overlaps the chlorite Mg-OH absorption. Consequently, it is more reliable to use the Fe-OH absorption feature for inferring the composition of chlorite rather than the Mg-OH feature. Pontual et al. (2008) have shown that this feature varies from 2245 nm for Mg-chlorite to 2261 nm for Fe-chlorite. The depth of the feature provides an estimation of the relative abundance of chlorite within the core/chips. 5.2 Results Congararra 1 mud rotary chips The mud rotary chips are composed mainly of kaolin (kaolinite), smectite (montmorillonite), white mica (muscovite), quartz and plagioclase (albite) (Figure 5.1). The white mica is tending to phengite (Al-OH: 2207 nm) at the top of the borehole to muscovite (Al- OH: 2202 nm) at the bottom. This is consistent with the muscovite observed throughout the diamond drill core. At the bottom of the mud rotary chips chlorite is detectible. Its Fe-OH absorption feature has an average wavelength of 2255 nm, similar to what is observed in the diamond tail. Figure 5.1: Mineral spectra summary plot of Congararra 1 mud rotary chips Congararra 1 diamond drill core The majority of the diamond drill core from Congararra 1 is composed of quartz, white mica (muscovite) and Fe-Mg chlorite. K-feldspar (microcline), plagioclase (albite) and dark mica (biotite) varies from minor to trace amounts throughout the drill hole (Figure 5.2). Congararra 1 borehole completion record 23

32 Figure 5.2: Mineral spectra summary plot of Congararra 1 diamond drill core. In addition to the above mentioned minerals, the core also contains carbonate (siderite-dolomite), kaolinite, smectite (montmorillonite) and trace goethite, in the range m DL. These minerals are possibly due to near-surface weathering of the metamorphic rock prior to deposition of the overlying sediments. Chlorite throughout the core tends to be Fe-Mg bearing, as evidenced by the average wavelength of the Fe-OH absorption feature at 2255 nm. The Al-OH absorption feature has a wavelength of 2200 nm throughout the core, indicative of muscovite. 5.3 Comparison with other logging The stratigraphy in the Congararra 1 borehole was interpreted from lithological textures and mineralogy based on knowledge from other boreholes in the region, regional geological mapping in the ENGONNIA, EULO and YANTABULLA 1:250,000 geological map sheets and borehole wireline geophysical data. These interpretations are tested against the spectral mineralogy of returned mud rotary chips and diamond drill core from the borehole in Figure 5.3A, B. The spectral mineralogy bears almost no correlation with the natural gamma and magnetic susceptibility data obtained down the hole or from mud rotary chips and diamond drill core. Packages of white mica, smectite, kaolin and plagioclase in the borehole are correlated with changes in the source materials of the sedimentary rocks of the Eromanga Basin, and indicate that sediment was being supplied from different sources, some of which included proximal igneous sources which contributed labile quartzose and feldspathic sediments. Other sediment sources would have been more distal, and included quartz-poor smectite clays. There is a small correlation between the appearance of plagioclase in the borehole and a slight increase in natural gamma emission that may be associated with the gradual decrease in weathering down the palaeoweathering profile on the basement rocks. 24 Congararra 1 borehole completion record

33 Figure 5.3A: Comparison between spectral mineralogy, interpreted stratigraphy and borehole rock properties data from Congararra 1. The spectral mineralogy legends in the log refer to the mud rotary drilled portion of the borehole <69 m TVD, and in the lower part to the diamond drilled portion to EOH. Congararra 1 borehole completion record 25

34 Figure 5.4B: legend for Figure 5.4A. The abrupt jump in kaolin relative abundance at ~88 m TVD, and the appearance or disappearance of other minerals, is associated with the change-over from the mud rotary to diamond drilling method in the borehole. 5.4 HyLogger data package The HyLogger data package consists of drill core data processed to Level 1F (all metadata tables updated, optimum database loadable level, further updates possible) that can be opened and viewed using The Spectral Geologist (TSG ) Viewer software. This software can be freely downloaded from CSIRO via the following link: This package also contains individual core tray images in.jpg format, and a mosaic of all the core trays arranged it order also in.jpg format. These images are referenced images and can be interactively interrogated when opened in TSG program. The data will also be made available through the AuScope National Virtual Core Library (NVCL) portal ( and Geoscience Australia s AUSGIN portal ( 5.5 HyLogger data reprocessing Geoscience Australia commissioned CSIRO Mineral Resources to perform a quality assessment of the HyLogger data package by reprocessing the original dataset described above. The results of the assessment indicate that the original TSA-derived mineralogy for the Congararra 1 borehole was a good match for the scalar-derived mineralogy calculated during the reprocessing (Lau et al., in prep). After acceptance, the reprocessed dataset will be available through the NVCL and AUSGIN portals listed above. 26 Congararra 1 borehole completion record

35 6 Groundwater I. C. Roach Local aquifers include Cenozoic gravels and the Mesozoic Wyandra Sandstone Member of the Cadna-owie Formation. Hydraulic heads around Congararra 1 are variable, generally with above ground-level heads to the northeast associated with active mound springs, and artesian water also occurring to the southeast. Local waterbores and their measured Standing Water Level (SWL) are listed in Table 6.1, highlighting the artesian water levels present in the region. Table 6.1: Local waterbores within the Congararra 1 vicinity highlighting the overall sub-artesian water pressures present in the area. Refer to Figure 2.2 for locations. Bore ID Distance & bearing Depth to main aquifer (m) SWL (m) when drilled (year)* Most recent SWL (m) or pressure (year) GW km NE NA (1954) 80 kpa (1989) GW km SE (1947) 1.5 (1984) GW km NW (1974) 1.5 (2007) GW km NNE NA (1961) A trickle (1989) GW km SSW (1939) NA *Negative values indicate SWL below ground surface. No artesian groundwater was detected in Congararra 1. The borehole intersected Quaternary sand, and sandy units in the Wallumbilla Formation, but no groundwater was made. This may be attributable to the fact that the borehole was drilled on the southwest side of a basement high. The locations of artesian water bores and active mound springs indicates that artesian water pressures occur along the eastern side of this basement high, but on the western side water pressures are sub-artesian to very slightly artesian depending on the proximity to the basement high. Congararra 1 borehole completion record 27

36 7 Acknowledgements Geoscience Australia and its project partners, the Geological Survey of New South Wales and the Geological Survey of Queensland, gratefully acknowledge the following organisations and people: Landholders Dan and Sally Muenster, Congararra Station Traditional owners the Murrawari People for cultural heritage monitoring DRC Drilling Pty Ltd, Dubbo NSW Fox Drilling Services Pty Ltd (Fox Campbell, licensed waterbore driller) for overseeing drilling operations through the Great Artesian Basin and ensuring the technical success of boreholes Greg Swain and Daniel Gray (Geoscience Australia On-site Representatives) for in-field management of drilling activities and budget monitoring Reviewer: Tim Barton OPM Consulting Pty Ltd for cultural heritage clearance work with the traditional owner cultural heritage monitors Southern Thomson Project team: o o o Geoscience Australia: Angela O Rourke (Project Manager), Narelle Neumann (former Project Manager), Tim Barton (former Acting Project Manager), Sheree Armistead, Patrice de Caritat, David Champion, Michael Doublier, James Goodwin, David Huston, Subhash Jaireth, Sharon Jones, Peter Maher (EASS, for assistance with land access and cultural heritage clearances), David McInnes, Andrew McPherson, Malcolm Nicoll, Ian Roach (Activity Leader), Paul Rossiter (Contracts and Probity), Roger Skirrow, Matilda Thomas, John Wilford, Geoscience Australia Laboratory and Science Services staff for support and analyses. GSNSW: Astrid Carlton, Chris Folkes (Activity Leader), John Greenfield, Phil Gilmore, Rosemary Hegarty (former Activity Leader), Bob Musgrave, Ned Stolz. GSQ: Dominic Brown, Paul Donchak, Laurie Hutton, David Purdy (Activity Leader), Janelle Simpson, Ian Withnall. Joel Fitzherbert and Mark Eastlake from the GSNSW are thanked for their assistance with thin-section examinations. 28 Congararra 1 borehole completion record

37 8 References Blevin, P. L., Redox and Compositional Parameters for Interpreting the Granitoid Metallogeny of Eastern Australia: Implications for Gold-rich Ore Systems. Resource Geology 54(3), Blevin, P. L. and Chappell, B. W., The role of magma sources, oxidation states and fractionation in determining the granite metallogeny of eastern Australia. Transactions of the Royal Society of Edinburgh: Earth Sciences 83, Blevin, P. L., Chappell, B. W. and Allen, C. M., Intrusive metallogenic provinces in eastern Australia based on granite source and composition. Transactions of the Royal Society of Edinburgh: Earth Sciences 87(1-2), Brodie, R. C., Ley-Cooper, Y., Crowe, M. C. A., McInnes, D. J. and Roach, I. C., in prep. The 2016 Southern Thomson AEM Survey: Southern Thomson Project. Geoscience Australia, Canberra. Record. Champion, D. C. and Chappell, B. W., Petrogenesis of felsic I-type granites: an example from northern Queensland. Transactions of the Royal Society of Edinburgh: Earth Sciences 83, Champion, D. C. and Heinemann, M. A., Igneous Rocks of Northern Queensland: 1: map and GIS explanatory notes. Australian Geological Survey Organisation, Canberra. Record 1994/11. Chappell, B. W., Aluminium saturation in I- and S-type granites and the characterization of fractionated haplogranites. Lithos 46, Chappell, B. W. and White, A. J. R., I- and S-type granites in the Lachlan Fold Belt, southeastern Australia. In: Xu, K. and Tu, G. (editors) Geology of granites and their metallogenic relations. Science Press, Beijing Chappell, B. W. and White, A. J. R., I- and S-type granites in the Lachlan Fold Belt. Transactions of the Royal Society of Edinburgh: Earth Sciences 83, Collins, W. J., Beams, S. D., White, A. J. R. and Chappell, B. W., Nature and origin of A-type granites with particular reference to southeast Australia. Contributions to Mineralogy and Petrology 80, Cook, A. G., McKellar, J. and Draper, J. J., Chapter 7.4 Eromanga Basin. In: Jell, P. A. (editor) Geology of Queensland. Geological Survey of Queensland, Brisbane Cross, A. J., Doublier, M., Purdy, D. J. and Hegarty, R., in prep. SHRIMP U-Pb ages from the Southern Thomson Project boreholes. Geoscience Australia, Canberra. Record. Debon, F. and Le Fort, P., A chemical and mineralogical classification of common plutonic rocks and associations. Transactions of the Royal Society of Edinburgh, Earth Sciences 73, Doublier, M., Purdy, D. J., Hegarty, R., Nicoll, M. and Zwingmann, H., in review. Structural domains of the southern Thomson Orogen, Australian Tasmanides. Australian Journal of Earth Sciences. El Bouseily, A. M. and El Sokkary, A. A., The relation between Rb, Ba and Sr in granitic rocks. Chemical Geology 16, Ewart, A., A review of the mineralogy and chemistry of Tertiary-Recent dacitic, latitic, rhyolitic and related salic volcanic rocks. In: Barker, F. (editor) Trondhjemites, Dacites and Related Rocks. Elsevier, Amsterdam Congararra 1 borehole completion record 29

38 Fitzpatrick, B. F., Frenda, G. A., Johnson, I. R., Wallis, G. R. and Wilson, R. B., ENNGONIA 1:250,000 geological series sheet SH Department of Mines, New South Wales, Sydney. Hawke, J. M. and Cramsie, J. N., Contributions to the geology of the Great Australian Basin in New South Wales. Geological Survey of New South Wales Bulletin 31, NSW Department of Mineral Resources, Sydney, 295 pp. Ishihara, S., Sawata, H., Arpornsuwan, S., Busaracome, P. and Bungbrakearti, N., The magnetite-series and ilmenite-series granitoids and their bearing on tin mineralization, particularly on the Malay Peninsular region. Geological Society of Malaysia Bulletin 11, Lau, I. C., legras, M. and Laukamp, C., in prep. Southern Thomson Orogen Mineral Spectroscopy. CSIRO, Perth. Le Maitre, R. W., Igneous Rocks. A Classification and Glossary of Terms. Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. 1st edition. Cambridge University Press. Le Maitre, R. W., Igneous Rocks. A Classification and Glossary of Terms. Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. 2nd edition. Cambridge University Press. Martin, H., Smithies, R. H., Rapp, R., Moyen, J.-F. and Champion, D., An overview of adakite, tonalite-trondhjemite-granodiorite (TTG), and sanukitoid: relationships and some implications for crustal evolution. Lithos 79, Mason, P. and Huntington, J. F., HyLogger 3 components and pre-processing: An overview. Northern Territory Geological Survey, Darwin, Technical Note National Uniform Drillers Licensing Committee, Minimum construction requirements for water bores in Australia Third edition. National Water Commission, Canberra, Ed Third. Online: Peccerillo, A. and Taylor, S. R., Geochemistry of Eocene caic-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contributions to Mineralogy and Petrology 58, Pontual, S., Merry, N. and Gamson, P., Spectral Interpretation Field Manual G-MEX. AusSpec International Ltd, Ed 3, Vol 1. Purdy, D. J., Hegarty, R. and Doublier, M., Basement geology of the southern Thomson Orogen. Australian Journal of Earth Sciences. Available at: Purdy, D. J., Hegarty, R., Doublier, M. and Simpson, J., Interpreting basement geology in the southern Thomson Orogen. In: Proceedings of the Australian Earth Sciences Convention 2014, Newcastle, Australia. Geological Society of Australia. Richards, J. P. and Kerrich, R., Adakite-like rocks: their diverse origins and questionable role in metallogenesis. Economic Geology 102, Roach, I. C. (editor) The Southern Thomson Orogen VTEMplus AEM survey: Using airborne electromagnetics as an UNCOVER application. Geoscience Australia, Canberra. Geoscience Australia Record 2015/29. Available at Roach, I. C., Brown, D. D., Purdy, D. J., McPherson, A. A., Gopalakrishnan, S., Barton, T. J., McInnes, D. J. and Cant, R., GSQ Eulo 1 borehole completion record. Geoscience Australia - Geological Survey of Queensland, Canberra. Geoscience Australia Record 2017/07 - Queensland Geological Record 2017/03, 55 pp. Roach, I. C., Bull, K. F., Champion, D. C., Cross, A. J., Folkes, C. B., Gilmore, P., Hegarty, R., Jones, S. L. and Tilley, D. B., 2018a. Tongo 1 borehole completion record: Southern Thomson Project. 30 Congararra 1 borehole completion record

39 Geoscience Australia-Geological Survey of New South Wales. GA Record 2018/07-GS2018/ Roach, I. C., Bull, K. F., Champion, D. C., Cross, A. J., Folkes, C. B., Gilmore, P., Hegarty, R., Jones, S. L. and Tilley, D. B., 2018b. Milcarpa 1 borehole completion record: Southern Thomson Project. Geoscience Australia-Geological Survey of New South Wales. GA Record 2018/13-GS2018/ Roach, I. C., Bull, K. F., Champion, D. C., Cross, A. J., Folkes, C. B., Gilmore, P., Hegarty, R., Jones, S. L., Tilley, D. B., Williams, B. J. and Wong, S., 2018c. Congararra 2 borehole completion record: Southern Thomson Project. Geoscience Australia-Geological Survey of New South Wales. GA Record 2018/09-GS2018/ Roach, I. C., Bull, K. F., Champion, D. C., Cross, A. J., Folkes, C. B., Gilmore, P., Hegarty, R., Hughes, K., Jones, S. L., Tilley, D. B. and Williams, B. J., 2018d. Janina 1 borehole completion record: Southern Thomson Project. Geoscience Australia-Geological Survey of New South Wales. GA Record 2018/11-GS2018/ Sajona, F. G. and Maury, R. C., Association of adakites with gold and copper mineralization in the Philippines. Comptes rendus de l Académie des sciences. Série II, Sciences de la terre et des planètes 326, Senior, B. R., Ingram, J. A. and Senior, D., The geology of the Quilpie, Charleville, Toompine, Wyandra, Eulo and Cunamulla 1:250,000 sheet areas, Queensland. Bureau of Mineral Resources, Geology and Geophysics Record 1969/13, Bureau of Mineral Resources, Geology and Geophysics Canberra. Streckeisen, A., Plutonic rocks. Classification and nomenclature recommended by the IUGS Subcommission on the Systematics of Igneous Rocks. Geotimes 18, Streckeisen, A., To each plutonic rock its proper name. Earth Science Reviews 12, Sun, W., Zhang, H., Ling, M.-X., Ding, X., Chung, S.-L., Zhou, J., Yang, X.-Y. and Fan, W., The genetic association of adakites and Cu Au ore deposits. International Geology Review 53, Wallis, G. R. and McEwan, P. R., Yantabulla 1:250,000 Geological Series Sheet SH/ Geological Survey of New South Wales Sydney. 1st edition. Whalen, J. B., Currie, K. L. and Chappell, B. W., A-type granites: Geochemical characteristics, discrimination and petrogenesis. Contributions to Mineralogy & Petrology 95, White, A. J. R., Clemens, J. D., Holloway, J. R., Silver, L. T., Chappell, B. W. and Wall, V. J., S- type granites and their possible absence in southwestern North America. Geology 14, White, R. M., Powell, R., Holland, T. J. B., Johnson, T. E. and Green, E. C. R., New mineral activity-composition relations for thermodynamic calculations in metapelitic systems. Journal of Metamorphic Geology 32, Congararra 1 borehole completion record 31

40 Appendix A Borehole construction The Congararra 1 borehole was constructed using a combination of mud rotary drilling to refusal into competent basement, then diamond drilling for the core tail. Drilling commenced with a mm (5 7/8 inch) diameter polycrystalline diamond (PCD) mud rotary drill bit and the installation of 69.0 m of mm OD SFJ screw thread casing. Drilling then continued into basement using a 96 mm OD HQ3 diamond drill bit and 3.0 m triple-tube core barrel to the EOH at m DL. The borehole was abandoned by removing the SFJ casing, then progressively cementing the borehole from bottom to top in stages through HQ3 drill pipe to surface. The borehole was rehabilitated by pushing surface soil back over the borehole cellar. The drilling mud sumps were fenced, left to dry out and were rehabilitated by the landholder by pushing the original surface soil back into the sumps. Drilling equipment consisted of a Sandvik DE880 multi-purpose drilling rig, a National Oilwell skidmounted mud pump, 20 mud tank, jack-up rod sloops, 40 mobile workshop/office/first aid room, lighting towers and support vehicles. 32 Congararra 1 borehole completion record

41 Figure 8.1: Congararra 1 borehole construction. Congararra 1 borehole completion record 33

42 Appendix B Drilling activities and consumables Table 8.1: Congararra 1 drilling times and production rates. Date Plod Shift Hole Rotary Mud Diamond Activity Size From To Total From To Total Drilling Time Active time total Inactive time total Non-chargeable time Total mm m m m m m m hr hr hr hr hr Friday, 1 September Night Congararra Site move, site set-up Saturday, 2 September Day Congararra Mud rotary drilling Saturday, 2 September Night Congararra Mix cement, run casing Sunday, 3 September Day Congararra Waiting on cement Sunday, 3 September Night Congararra 1 HQ Drill out cement, diamond drilling Monday, 4 September Day Congararra 1 HQ Diamond drilling, cement up hole, site tear-down 34 Congararra 1 borehole completion record

43 Table 8.2: Congararra 1 drilling consumables used. Date Plod Shift Hole HWT (4 1/2 SFJ) Darby Plug Aus-Gel Xtra (bentonite) Cement AMC Pac-L AMC Pac-R XT Rod Grease /m HQ 25 kg 20 kg 25 L 25 kg 17 kg Total Friday, 1 September Night Congararra 1 Saturday, 2 September Day Congararra Saturday, 2 September Night Congararra Sunday, 3 September Day Congararra 1 17 Sunday, 3 September Night Congararra 1 1 Monday, 4 September Day Congararra 1 Congararra 1 borehole completion record 35

44 Appendix C Petrophysical equipment details C.1 Borehole wireline logging equipment Mt Sopris QL40 GRA natural gamma tool SN 6060 Mt Sopris QL40 MS magnetic susceptibility tool SN ALT Matrix data acquisition system SN 0D0D Auslog W winch SN T199 with 1750 m of 4-conductor cable. C.2 Hand-held magnetic susceptibility logging equipment CoRMaGeo RT-1 magnetic susceptibility meter SN (GA). C.3 Analytical balance equipment (density determination) A & D Instruments EP-41KA Industrial Balance, serial number , quoted accuracy ± 1.0 g. 36 Congararra 1 borehole completion record

45 Appendix D Petrophysical data acquisition and processing D.1 Data acquisition and processing Borehole wireline petrophysical data were acquired during the mud rotary and diamond drilling operations, nominally in the open borehole as each section of the borehole was drilled and before steel casing was inserted (Table 8.3). Data from each logging run in the borehole were assessed for quality and were then stitched together to create a final run of data for the length of the borehole where possible. Table 8.3: Borehole wireline data acquisition steps in Congararra 1 Date Length logged (m DL) Borehole casing size Properties logged m DL mm open hole to 69.0 m DL Natural gamma, magnetic susceptibility m DL mm OD steel to 69.0 m DL, then 96.0 mm open hole to m DL Natural gamma, magnetic susceptibility Hand-held magnetic susceptibility data were acquired in the field along the entire length of the borehole from the mud rotary drilled chips at 1.0 m intervals and from the diamond drill core at 0.5 m intervals. These data were used to produce a final magnetic susceptibility log of the borehole. Measurements were made on mud rotary drilled chip samples by placing the sample vial on top of the magnetic susceptibility meter and repeatedly measuring the sample to obtain a repeatable value. For magnetic susceptibility measurements on diamond drill core the plastic diamond drill core trays used for the drilling program were elevated above the work tables on a stack of two empty core trays to ensure no interference from steel in the work tables. Point observations were then obtained at 0.5 m intervals by repeated measurements on the same point to obtain a repeatable value. Magnetic susceptibility measurements on core were multiplied by the recommended compensation factor for the core size according to the manufacturer s instructions. Hand-held magnetic susceptibility data were verified by borehole wireline magnetic susceptibility data. The hand-held magnetic susceptibility data are used in preference to the borehole wireline data. D.2 Equipment calibration Borehole wireline tools were calibrated according to the manufacturer s Standard Operating Procedures (SOPs) described in the user manuals, also described in Roach et al. (2017), apart from the natural gamma tool which was calibrated in the factory and is not capable of being calibrated in the field. In the field equipment was connected to the ALT Matrix data acquisition system and energised for a period of at least 15 minutes in the borehole to equilibrate temperature with the bore fluid before commencing calibration. Equipment was fully tested in Canberra before commencing borehole wireline logging operations to ensure that it was stable and gave repeatable results prior to the field campaign and calibration drift was checked in the field at every use to ensure data repeatability. Congararra 1 borehole completion record 37

46 The primary handheld magnetic susceptibility meter used to obtain data on mud rotary drilling chips and diamond drill core (CoRMaGeo RT-1 SN ) was calibrated by the manufacturer before commencing the field operations. D.3 Data processing Petrophysical data were processed using the following processing stream: Levelling raw borehole wireline data files to a common datum (ground level) and interpolating the sampling interval to even increments (0.05 m) using WellCAD. Combining data from different logging runs into a single data file and removing overlapping data. Bridging any single-sample data dropouts caused by transient telemetry errors during acquisition by averaging data across the gap, leaving larger data gaps between successive logging runs as nulls. Editing natural gamma data to remove the effects of gamma-ray attenuation due to casing and changes in borehole diameter in overlapping data from earlier and later logging runs by applying a bias to attenuated data to achieve a full run of apparent open hole natural gamma data. Editing handheld magnetic susceptibility data to remove the effects of any verified steel particle contamination. Produce a final LAS-format data file of: o o Open hole natural gamma Handheld magnetic susceptibility 38 Congararra 1 borehole completion record

47 Appendix E Lithological and stratigraphic log FROM TO FROM TO GA LITHOLOGY GA QUALIFIER COLOUR DESCRIPTION Grain size PROVINCE STRATNAME MAPSYMBOL m DL m DL m TVD m TVD Clay Silt Vfine Fine Med Coarse Vcoarse Granule Pebble Cobble Alluvial sediment ferruginous L br-gy Well sorted, light brown-grey, ferruginised, very well sorted clay to very fine-grained sand Alluvial sediment ferruginous L br-gy Poorly sorted, light red-brown, ferruginised, very well sorted clay to finegrained sand X X X No province Quaternary alluvium Qa X X X X X No province Quaternary alluvium Qa Alluvial sediment ferruginous Rd-br Light grey, ferruginised, poorly sorted clay to quartzose granules X X X X X No province Quaternary alluvium Qa Silcrete Wh-gy-rd White-grey silcreted fine sand, ferruginised in the top 1 m X Eromanga Basin Wallumbilla Formation Klu Arenite L gy Light grey, well sorted, well rounded quartz arenite, lithics and silcrete X X Eromanga Basin Wallumbilla Formation Klu Sandstone L gy Medium-grained poorly sorted lithic sandstone with common coarse lithic fragments X X Eromanga Basin Wallumbilla Formation Klu Silcrete L gy Poorly sorted, rounded, silcreted silt to medium-grained sand X X X X Eromanga Basin Wallumbilla Formation Klu Arenite Wh-gy Poorly sorted very coarse sandstone with 25% lithics X Eromanga Basin Wallumbilla Formation Klu Sandy siltstone Y-br-gy Yellow-brown-grey siltstone to fine sandstone X X X Eromanga Basin Wallumbilla Formation Klu Silcrete Wh-gy Silcreted siltstone and fine-medium-grained sandstone with minor lithics X X Eromanga Basin Wallumbilla Formation Klu Silty sand Wh-rd-y-dk br Poorly sort silt and sand, silcrete fragments X X X X X Eromanga Basin Wallumbilla Formation Klu Arenite Br-pnk-y Poorly sorted lithic sandstone with silcrete chips and yellow clay X X X X X Eromanga Basin Wallumbilla Formation Klu Sandy siltstone micaceous Gr-gy-pnk-rd-dk br Green-grey micaceous siltstone and sandstone fragments X X X X X X Eromanga Basin Wallumbilla Formation Klu Siltstone micaceous Green-grey micaceous siltstone X Eromanga Basin Wallumbilla Formation Klu Sandy siltstone micaceous Dk br-rd Green-grey micaceous siltstone and poorly sorted lithic sandstone fragments Sandy siltstone micaceous Dk br Dark brown micaceous siltstone with medium- to very coarse-grained quartz and lithics Arenite Dk br-gy Subrounded fine-grained sand, medium- to coarse-grained lithics and quartz Sandy siltstone micaceous Dk br Friable siltstone, moderately well sorted lithic and micaceous sandstone and quartz grains Gravelly silty sand Gy-gr-beige Friable grey-green siltstone, beige sandstone with rounded coarse gravelly quartz grains X X X X Eromanga Basin Wallumbilla Formation Klu X X X X Eromanga Basin Wallumbilla Formation Klu X X X Eromanga Basin Wallumbilla Formation Klu X X X X Eromanga Basin Wallumbilla Formation Klu X X X X X Eromanga Basin Wallumbilla Formation Klu Gravelly sand Gy Coarse-grained gravelly sandstone with lithics and rounded quartz grains X X Eromanga Basin Wallumbilla Formation Klu Saprolite Gy Coarse-grained gravelly silty sandstone with lithics and rounded quartz grains Gneiss V dk gy-bk Angular quartz, biotite, cream-coloured feldspar with green alteration rims, and foliated schistose lithic fragments X X X X X Thomson Orogen X X X X Thomson Orogen Granodiorite Gy Pegmatitic vein X X X X Thomson Orogen Gneiss V dk gy-bk Angular quartz, biotite, cream-coloured feldspar with green alteration rims, and foliated schistose lithic fragments X X X X Thomson Orogen Granodiorite Gy Pegmatitic vein with graphic quartz-feldspar intergrowth X X X X Thomson Orogen Gneiss V dk gy-bk Angular quartz, biotite, cream-coloured feldspar with green alteration rims, and foliated schistose lithic fragments X X X X Thomson Orogen Congararra 1 borehole completion record 39

48 Appendix F Deviation survey Deviation survey by Reflex EZ GYRO. Diamond drill core orientation by Reflex ACT III RD device. Table 8.4: Deviation survey data for Congararra 1. Length Azimuth Inclination Hade m DL Degrees magnetic Degrees* degrees *Inclination: degrees from horizontal, negative downwards 40 Congararra 1 borehole completion record

49 Appendix G Whole rock geochemistry Samples of diamond drill core from 69.0 m DL to m DL were taken for whole-rock geochemical analysis. Analyses were performed by Bureau Veritas in Perth, Western Australia. Major element abundances were determined by X-Ray Fluorescence (XRF), with results shown in wt. %. Exceptions include FeO, which was determined volumetrically, and Loss-On-Ignition (LOI), which was determined using a robotic Trace Gas Analysis (TGA) system at 110 C and 1000 C. Fe 2 O 3 * is regarded as total Fe, as Fe 2 O 3. Fe 2 O 3 is calculated by difference (Fe 2 O 3 * *FeO). Trace element analysis is by laser ablation ICP-MS on the fused glass disk (lithium metaborate fusion), except for S, which has been calculated from the analysed SO 3 value. Limits of Detection (LD) and units of measure (ppm or ppb) shown are in the columns). Analyses below detection are shown as negative LD, e.g., Table 8.5: Whole-rock major element geochemical data for Congararra 1. SAMPLEID 17/ /1065 ENTITYID Congararra 1 Congararra 1 ROCKTYPE granodiorite metasediment Depth_top (m) Depth_bottom (m) Lab LD Veritas Veritas Major elements wt. % wt. % SiO TiO Al 2O Fe 2O 3* Fe 2O FeO MnO MgO CaO Na 2O K 2O P 2O SO Cl LOI Total Congararra 1 borehole completion record 41

50 Table 8.6: Whole-rock trace element geochemical data for Congararra 1 SAMPLEID 17/ /1065 ENTITYID Congararra 1 Congararra 1 ROCKTYPE granite metasediment Depth_top (m) Depth_bottom (m) Lab LD Veritas Veritas Trace elements ppm ppm Ba Rb Sr Pb Th U Zr Hf Nb Ta Y La Ce Nd Sc V Cr Ni Ga Pr Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Ag As Be Bi Cd Cs Congararra 1 borehole completion record

51 SAMPLEID 17/ /1065 ENTITYID Congararra 1 Congararra 1 ROCKTYPE granite metasediment Depth_top (m) Depth_bottom (m) Lab LD Veritas Veritas Trace elements ppm ppm Cu Ge In Mn Mo Re S Sb Se Sn Te Ti Tl Zn Congararra 1 borehole completion record 43

52 Appendix H Metallogenic and Igneous classifications Metallogenic and igneous classifications here follow on from that used by Champion and Heinemann (1994), augmented by more recent petrogenetic schemes, including those of Blevin et al. (1996) and Blevin (2004). In addition, given the (controversial) suggestion, e.g. Sajona and Maury (1998) and Sun et al. (2010), that igneous rocks of adakitic composition may be associated with copper and gold mineralisation, we have included geochemical indicators of adakitic composition also (using parameters from Martin et al., 2005). All indicators are used to assist with both classifying the units in question and also with understanding the metallogenic potential of the units. These indicators are further explained below. Rock type classification (Figure 3.5A): Igneous classification follows Streckeisen (1973); (1976), based on drill core and thin section observation, augmented by the plutonic rock classification of Debon and Le Fort (1983). Igneous rock type: All igneous units were classified into one of 4 possible classes: I-, S-, or A-type (e.g. Collins et al., 1982; Chappell and White, 1992), or M-type for mafic igneous rocks with less than 52% SiO 2 (Le Maitre (1989) suggests 52% SiO 2 as the boundary between mafic and intermediate classes and this is adhered to). Igneous units were classified as I- or S-type based on the available petrographic descriptions (e.g. presence of hornblende) and whole-rock geochemistry, using the parameters listed by Chappell and White (1984), and White et al. (1986). A-type units were discriminated from I-type units on the basis of whole rock geochemistry following the guidelines of Collins et al. (1982) and Whalen et al. (1987). Units where the designation is uncertain are designated with a question mark, e.g., S-type? Potassium content (Figure 3.5B): Potassium content of igneous rocks can be indicative of both compositional maturity of the igneous unit in question and of the nature of the source protolith, both of which may have implications of metallogeny, e.g., shoshonitic rocks may indicate mantle metasomatism, which has been implicated in copper and gold mineralisation. Previous studies on volcanic rocks, e.g. Peccerillo and Taylor (1976) and Ewart (1979), have utilised K 2 O-SiO 2 plots to distinguish low-, medium- and high-k igneous rocks. Le Maitre (1989) reinforced the use of these terms as qualifiers for standard volcanic nomenclature. This concept has been extended here and applied to all igneous rocks (intrusive and extrusive). A/CNK: A/CNK (= molecular (Al/(Ca+Na+K)) is a measure of the Aluminium saturation Index of the rock in question, i.e., metaluminous (A/CNK < 1.0) or peraluminous (A/CNK > 1.0). As outlined by Chappell (1999) this measure is useful in identifying igneous type. It also has metallogenic implications, e.g., porphyry copper deposits are not generally related to peraluminous granites. A/CNK is affected by alteration (mobility of alkalis) so care needs to be taken in interpretation. Redox (Figure 3.5C): Champion and Heinemann (1994), based on work by Ishihara et al. (1979) and Blevin and Chappell (1992), used the Fe 2 O 3 /FeO ratio as a measure of the degree of oxidation. As shown by both Ishihara et al. (1979) and Blevin and Chappell (1992), the oxidation state of a magma can play an important role in associated metallogeny, e.g. Cu-Au with strongly oxidised magmas, Sn with reduced to strongly reduced magmas. 44 Congararra 1 borehole completion record

53 Magnetic susceptibility (in SI x 10-5 units): Is a proxy for the current oxidation state of the unit in question, as it is typically a measure of the presence of absence of magnetite, i.e. oxidised magma. Care needs to be taken as it may be indicative of other minerals, e.g. pyrrhotite, or, in the case of strongly oxidised systems with hematite and no magnetite, misleading. Note that the indicative oxidation state as indicated by Fe 2 O 3 /FeO and magnetic susceptibility may not be in agreement for other reasons also, commonly reflecting presence of alteration and/or weathering. Redox-Fractionation: As discussed by Blevin and Chappell (1992), Blevin et al. (1996) and Blevin (2004), the interplay between the oxidation state and the compositional evolution of a magma (e.g. as indicated by fractionation) can play a significant role in associated metallogeny. This largely relates to the behaviour of ore elements such as Cu and Sn in the magma and when such elements are at their greatest concentration. For example, reduced conditions will favour Sn in the divalent state and hence make this element more incompatible, such that Sn contents will increase with increasing fractionation, and will be at maximum levels in reduced-fractionated magmas. Fractionation (Figure 3.5D): As documented by Blevin and Chappell (1992) and Blevin et al. (1996), compositional evolution of magmas can be an important factor in metallogeny. There are a number of ways of constraining the degree of fractionation (e.g. Champion and Chappell, 1992; Champion and Heinemann, 1994; Blevin, 2004). We have used three ratios, based on relative behaviours of elements of differing compatibility, largely related to feldspars: 1. Rb/Sr: uses the ratio of the mostly incompatible element Rb over the strongly compatible element Sr (largely incorporated in plagioclase). The Rb/Sr ratio increases with increasing fractionation, from values much less than 1.0 to 10 to 100+ (e.g. Champion and Chappell, 1992). Blevin et al. (1996) used this ratio in their redox-fractionation metallogenic plot (e.g. Figure 3.5E). 2. Ba-Rb-Sr: The ternary relationship (Figure 3.5D) utilises the mostly incompatible Rb, the strongly compatible Sr, and the element Ba which with increasing fractionation changes from incompatible to compatible (reflecting K-feldspar and biotite crystallisation). We follow Champion and Heinemann (1994) in using the fields of El Bouseily and El Sokkary (1975). 3. K/Rb: Champion and Chappell (1992) showed that the K/Rb ratio strongly decreases in strongly fractionated felsic igneous rocks, from values around and above, down to values <30. In addition, as discussed by Blevin (2004), for example, rocks from continental and island arcs tend to have elevated K/Rb ratios, e.g. around and , respectively, illustrating that K/Rb can also be utilised, like K content, as an indicator of source protolith, i.e., tectonic regime. Adakite signature: Recent authors, e.g. Sajona and Maury (1998) and Sun et al. (2010), have suggested that adakitic rocks may be associated with Cu-Au mineralisation. Although this association is controversial and strongly disputed by some, e.g. Richards and Kerrich (2007), it is included in the current metallogenic analysis for completion. As discussed by many authors, e.g. Martin et al. (2005), adakitic rocks have a characteristic signature elevated Sr, Sr/Y, LREE/HREE, MREE/HREE, low HREE, Y which is consistent with derivation from mafic protoliths at high pressures leaving a garnetbearing and plagioclase-free residue (although alternative origins have been proposed). Accordingly, we have utilised a number of indicators: (Gd/Yb) N (=primitive mantle (PM)-normalised Gd/PM-normalised Yb): this variable provides an indication of the fractionation of the heavy rare earth elements (HREE). This value will be elevated for rocks with an adakitic heritage, but generally low (~1-2 for non-adakitic rocks). Congararra 1 borehole completion record 45

54 Sr/Y: this ratio can be used a direct measure of the elevated Sr, low Y (& HREE) nature of adakitic rocks, which have Sr/Y values of and greater. Unfortunately, this is non-unique and rocks derived from adakitic protoliths can also inherit similar ratios. Eu/Eu* (= Eu/ square root (Sm + Gd)): this ratio measures the mismatch between the actual Eu contents of the unit and what the Eu contents would have been if present at the same levels (normalised to chondrite) as the rare earth elements of slightly smaller and higher atomic numbers (e.g., Sm, Gd). Unlike other rare earth elements, Eu is commonly present in the divalent form in most magmatic systems and behaves compatibly (commonly substituting into plagioclase). As such the Eu/Eu* is a direct measure of whether or not plagioclase has played a significant role in the genesis of an igneous unit. Adakitic rocks typically have values of 1 (or greater). Eu/Eu* can also be used as an indicator of fractionation as this ratio can decrease to low levels (<0.1) in very strongly fractionated rocks. Na 2 O/K 2 O: adakitic rocks are typically characterised by low K 2 O contents (Low-K to medium-k) with elevated Na 2 O/K 2 O ratios greater than, often much greater than, 1.0. It is noted that many of these parameters can be directly affected by alteration as well as weathering so care needs to be taken with their use. Importantly, the presence of alteration may be indicated by variable results using the above parameters, for example, the combination of high-k coupled with high Na 2 O/K 2 O, is unusual and immediately raises suspicions of alteration. 46 Congararra 1 borehole completion record

55 Appendix I Borehole log Congararra 1 borehole completion record 47

56 Congararra 1 Date completed: Borehole orientation: Inclined -80 /180 AHD elevation (AUSGeoid2020): 96 m Longitude / easting: / m Latitude / northing: / m Datum: GDA94 / MGA94Z55S 0 Borehole construction 0 Stratigraphy 200 Lithology 100 TVD (m) 0 DL (m) 200 Magnetic susceptibility (SI x 10-5) Natural gamma (API) 400 Location: 70 km NNW of Bourke, New South Wales Operator: Geoscience Australia for the Geological Survey of New South Wales 0 Qa Klr Bas Lithology Stratigraphy Alluvial sediment Qa - Quaternary alluvium Silcrete Klr - Rolling Downs Group Arenite Bas - Basement Sandstone Sandy siltstone Siltstone Gravelly silty sand Gravelly sand Saprolite Gneiss Granodiorite Construction Cement Casing Open hole