NORTHERN TERRITORY GEOLOGICAL SURVEY RECORD 2019-009
Summary of results. Re–Os molybdenite dating of copper and tungsten mineralisation in the Tennant Creek mineral field, and Hatches Creek and Mosquito Creek tungsten fields, Warramunga Province.
MV McGloin and RC Creaser
i NTGS Record 2019-009 DEPARTMENT OF PRIMARY INDUSTRY AND RESOURCES MINISTER: Hon. Paul Kirby, MLA CHIEF EXECUTIVE: Alister Trier
NORTHERN TERRITORY GEOLOGICAL SURVEY EXECUTIVE DIRECTOR: Ian Scrimgeour
BIBLIOGRAPHIC REFERENCE: McGloin MV1 and Creaser RC2, 2019. Summary of results. Re–Os molybdenite dating of copper and tungsten mineralisation in the Tennant Creek mineral field, and Hatches Creek and Mosquito Creek tungsten fields, Warramunga Province. Northern Territory Geological Survey, Record 2019-009.
(Record / Northern Territory Geological Survey ISSN 1443-1149) Bibliography ISBN: 978-0-7245-7352-3 (PDF)
Keywords: geochronology, isotope dilution, solvent extraction, anion chromatography, negative thermal ionization, mass spectrometry, rhenium–osmium, molybdenite, tungsten, vein, mineralisation.
EDITOR: GC MacDonald. Graphics and layout: KJ Johnston.
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1 now at Independence Group NL, Suite 4, Level 5 South Shore Centre, 85 South Perth Esplanade, South Perth WA 6151 2 Department of Earth & Atmospheric Sciences, University of Alberta, Edmonton, AB Canada T6G2R3
NTGS Record 2019-009 ii Summary of results. Re–Os molybdenite dating of copper and tungsten mineralisation in the Tennant Creek, Hatches Creek and Mosquito Creek mineral fields, Warramunga Province. By MV McGloin and RC Creaser
SUMMARY
This Record details rhenium–osmium (Re–Os) geochronology for molybdenite from one copper–molybdenum prospect (Explorer 27), two tungsten deposits (Pioneer, Hill of Leaders) and one tungsten prospect (North Curtis) in the Warramunga Province of central Australia. Molybdenite was dated to determine absolute ages of mineralised quartz veins and to provide an indication of the timing of copper and tungsten mineralisation in the area. Two samples of molybdenite associated with chalcopyrite in quartz veins were collected from the Explorer 27 prospect in the Tennant Creek mineral field. Sample TC18MVM001 yielded a Re–Os model age of 1711 ± 8 Ma, and sample TC18MVM002 yielded a Re–Os model age of 1719 ± 8 Ma. These ages are interpreted to record the timing of copper and molybdenum mineralisation at Explorer 27. The ages indicate an episode of copper mineralisation in the Tennant Creek mineral field younger than the reported age of most ironstone-related copper–gold deposits in the same mineral field. These results represent the first time that copper mineralisation of this age has been reported in the Tennant Creek mineral field. One molybdenite sample (FR18MVM001), associated with scheelite and wolframite in a quartz vein, was collected from the Pioneer tungsten deposit in the Hatches Creek tungsten field. This sample yielded a Re–Os model age of 1714 ± 8 Ma. This new model age is interpreted as a direct age for tungsten mineralisation at the deposit. It is broadly consistent with previous Ar–Ar ages and is slightly older than Re–Os molybdenite ages from mineralisation elsewhere in the Hatches Creek tungsten field. One molybdenite sample (BC18MVM003), associated with scheelite in a quartz vein at the Hill of Leaders tungsten deposit in the Mosquito Creek tungsten field, yielded an impossible Re–Os model age of 6713 ± 30 Ma. Analysis of this sample was repeated and yielded another geologically impossible age of 4940 ± 20 Ma. One further molybdenite sample (BC18MVM006), from a quartz vein associated with tungsten mineralisation from the North Curtis tungsten prospect in the same tungsten field as Hill of Leaders, yielded a Re–Os model age of 1777 ± 9 Ma. This age is younger than the age of the Hill of Leaders Granite that hosts the mineralisation and is tentatively interpreted as a mineralisation age. The new molybdenite ages reported in this study from the Tennant Creek and Hatches Creek fields are similar; they also share a similar timing to copper and tungsten mineralisation elsewhere in central Australia: for example, tungsten mineralisation at the Juggler prospect in the ca 1720 Ma Elkedra Granite in the Davenport Province, and further afield, granite-related copper and tungsten mineralisation in the eastern Aileron Province (eg Jervois mineral field, Bonya Hills area, Molyhil). Although further work is necessary, this similarity may suggest a widespread granite-related copper and tungsten mineralising episode at ca 1730–1680 Ma in the region.
iii NTGS Record 2019-009 CONTENTS
Summary...... iii Introduction...... 1 Re–Os molybdenite dating...... 1 Analytical procedures...... 1 Sample preparation...... 1 Analysis...... 1 Samples analysed...... 4 Chalcopyrite–molybdenite–pyrite-bearing quartz vein, Explorer 27 prospect (TC18MVM001)...... 4 Chalcopyrite–molybdenite–pyrite-bearing quartz vein, Explorer 27 prospect (TC18MVM002)...... 5 Molybdenite–scheelite–wolframite-bearing quartz vein, Pioneer deposit (FR18MVM001)...... 7 Molybdenite–scheelite-bearing quartz vein, Hill of Leaders deposit (BW18MVM003)...... 10 Molybdenite–scheelite–wolframite-bearing quartz vein, North Curtis prospect (BM18MVM006)...... 12 Acknowledgments...... 14 References...... 14
FIGURES
1. Location of sample locations in the Warramunga Province including the Tennant Creek, Hatches Creek and Mosquito Creek mineral fields...... 2 2. Photograph of drill core for sample site TC18MVM001, Explorer 27 prospect...... 4 3. Geological map of the Explorer 27 prospect and surrounding area...... 5 4. Photograph of drill core for sample site TC18MVM002, Explorer 27 prospect...... 6 5. Geological map of the Pioneer deposit and surrounding area...... 7 6. Photographs of sample site for FR18MVM001, Pioneer deposit...... 8 7. Geology of the Pioneer deposit of the Hatches Creek tungsten field...... 8 8. Geological map of the Mosquito Creek tungsten field.. 10 9. Photographs of sample site for BW18MVM003, Hill of Leaders deposit...... 11 10. Photographs of the Hill of Leaders Granite...... 12 11. Photographs of sample site for BW18MVM006, North Curtis prospect...... 13
TABLES
1. Summary of molybdenite Re–Os model ages and sample details...... 3 2. Summary of Re–Os age determinations...... 3
NTGS Record 2019-009 iv INTRODUCTION that have experienced multiple hydrothermal, magmatic and metamorphic episodes. This is because molybdenite This Record presents new Re–Os molybdenite typically is not complicated by overgrowths that are geochronology results from four previously undated common in minerals like zircon, monazite and xenotime deposits and prospects in the Warramunga Province of (Stein et al 2001; but see Aleinikoff et al 2012 for a counter central Australia: the Explorer 27 copper–molybdenum example). prospect in the Tennant Creek mineral field in TENNANT The Re–Os molybdenite system has produced lower CREEK1, the Pioneer tungsten deposit in the Hatches closure temperatures in some examples (at least ~550°C; Creek tungsten field in FREW RIVER, and both the Hill eg Suzuki et al 2001) compared to more traditional U–Pb of Leaders tungsten deposit and the North Curtis tungsten mineral chronometers (~800–600°C; eg zircon, monazite, prospect in the Mosquito Creek tungsten field in BONNEY titanite, baddeleyite). However, closure temperatures are WELL. The Warramunga Province covers the area in and usually higher than many other chronometers (ie Rb–Sr, around Tennant Creek and is located approximately 375 km K – Ar, Ar–Ar; eg muscovite at ~350ºC; Schaefer 2016). north of Alice Springs (Figure 1). Other studies have demonstrated that closure temperatures Copper–gold and tungsten mineralisation are widespread for the molybdenite Re–Os system can be higher depending in the Warramunga Province; it occurs within the Tennant on the deposition system (~800°C; Bingen and Stein 2003, Creek mineral field, and the Hatches Creek, Wauchope and Selby et al 2004). Mosquito Creek tungsten fields (eg Ferenczi and Ahmad 1996, Fraser et al 2008, Donnellan 2013a, b; McGloin ANALYTICAL PROCEDURES et al 2019). In many cases, the age of copper or tungsten mineralisation is relatively well understood (eg Compston Sample preparation and McDougall 1994, Warren et al 1995, Fraser et al 2008, Donnellan 2013a, 2013b). Other prospects and deposits have Re–Os molybdenite dating was conducted at the University less certain, and in some cases, only inferred mineralisation of Alberta in December 2018 and January 2019 on samples ages (eg Wyborn et al 1998, McInnes et al 2008, Donnellan collected in the field in October 2018 by the Northern 2013a–b, Skirrow et al (in review), McGloin et al 2019). Territory Geological Survey. Molybdenite was separated This study was conducted to constrain the timing of by metal-free crushing, followed by gravity and magnetic tungsten mineralisation in the Tennant Creek mineral field, concentration methods as described by Selby and Creaser and Hatches Creek and Mosquito Creek tungsten fields. (2004). Sample weights are reported in Table 2. It also provides an opportunity to test the validity of the Re – Os method for dating tungsten mineralising events in Analysis the region. This Record documents the sampled locations, The methods used for molybdenite analysis are described geological context, descriptions of the targeted molybdenite, in detail by Selby and Creaser (2004). The 187Re and 187Os and the relevant analytical data. The sampled locations are concentrations in molybdenite were determined by isotope shown in Figure 1. Table 1 lists a summary of the results. dilution mass spectrometry using Carius-tube, solvent A brief discussion and interpretation of the isotopic data is extraction, anion chromatography and negative thermal also included. ionization mass spectrometry (ID–NTIMS) techniques. A mixed double spike containing known amounts of Re–Os MOLYBDENITE DATING isotopically enriched 185Re, 190Os, and 188Os was used (Markey et al 2007). Isotopic analysis was carried out on The Re–Os chronometer for dating molybdenite is a robust a ThermoScientific Triton mass spectrometer by Faraday and reliable chronologic tool (Stein et al 2001, Norman et al collector. Total blanks for Re and Os are less than 3 picograms 2004 and references therein). Re–Os is a closed isotopic and 2 picograms respectively, which are insignificant for the system in molybdenite during high-grade metamorphism Re and Os concentrations in molybdenite. The Reference and deformation, even under granulite facies conditions Material 8599 Henderson molybdenite (Markey et al 2007) (Bingen and Stein 2003). It is not commonly susceptible was used as an analysis standard. During the past year, this to chemical and thermal disturbances (Stein et al 2001). standard returned an average Re–Os date of 27.76 ± 0.08 Ma The Re–Os system appears particularly useful in terranes (n = 8), indistinguishable from the reference age value of 27.66 ± 0.1 Ma (Wise and Watters 2011). All uncertainties 1 Names of 1:100 000 and 1:250 000 mapsheets are shown in are quoted at 2σ level, and comprise all known analytical small and large capital letters, respectively, eg Short Range, uncertainty, including uncertainty in the decay constant of TENNANT CREEK 187Re.
1 NTGS Record 2019-009 129°00'130°30' 132°00'133°30' 135°00'1136°30' 38°00'
11°
Carpentaria Basin
Money Shoal Basin 12° Nhulunbuy Bonaparte Basin DARWIN Arafura Basin Carpentaria Jabiru 13° Basin Pine Creek Arnhem Orogen Province Fitzmaurice Basin
14° Daly Basin Katherine McArthur Basin
15° Victoria Basin
Wolfe Basin Borroloola 16°
17°
Birrindudu Basin Kalkarindji South Province 18° Nicholson Basin
TANAMI REGION TENNANT Lawn 19° Hill Wiso Basin Platform Birrindudu Basin TC18MVM001 Tennant Creek TC18MVM002
20° Warramunga Province BW18MVM006 BW18MVM003 Georgina Basin REGION Canning 21° Basin FR18MVM001 Davenport Aileron Province Province
ARUNTA REGION
22°
Ngalia Basin Aileron Province 23° Irindina Warumpi Province Province
ALICE SPRINGS 24°
Amadeus Basin Aileron Province NORTHERN TERRITORY
25° Yulara Eromanga Basin
Musgrave Province 26° FR18MVM001 A18-504.ai Archaean Neoproterozoic-Palaeozoic molybdenite sample Palaeo-Mesoproterozoic orogens Mesozoic-Cenozoic 02100 00 km Palaeo-Mesoproterozoic basins Figure 1. Regional geological map of the Northern Territory showing location of molybdenite samples reported in this Record.
NTGS Record 2019-009 2 Table 1. Summary of molybdenite dating results. Re–Os model ages in bold are considered mineralisation ages; model ages in italics are considered geologically meaningless. Sample description Prospect/deposit Mineral field Sample No Target MGA94 Easting Northing Re–Os mineral zone (mE) (mN) model age (Ma) Chalcopyrite- Explorer 27 Tennant Creek TC18MVM001 molybdenite 53 K 378009 7864932 1711 ± 8 molybdenite-bearing Cu–Mo prospect mineral field quartz vein Chalcopyrite- Explorer 27 Tennant Creek TC18MVM002 molybdenite 53 K 378009 7864932 1719 ± 8 molybdenite-bearing Cu–Mo prospect mineral field quartz vein Molybdenite-tungsten- Pioneer W deposit Hatches Creek FR18MVM001 molybdenite 53 K 518579 7692107 1714 ± 8 bearing quartz vein mineral field FR18MVM001RPT 1714 ± 8 Molybdenite-scheelite- Hill of Leaders W Mosquito Creek BW18MVM003 molybdenite 53 K 463087 7753693 6713 ± 30 bearing quartz vein deposit tungsten field BW18MVM003RPT 4940 ± 24 Molybdenite-scheelite- North Curtis Mosquito Creek BW18MVM006 molybdenite 53 K 462172 775467 1777 ± 9 wolframite-bearing W prospect tungsten field quartz vein
Table 2. Summary of Re–Os age determinations. All uncertainties are quoted to 2σ uncertainties. Re–Os model ages in bold are considered mineralisation ages. ppb = parts per billion, ppm = parts per million.
Sample Re 187Re 187Os Model age ± 2σ Sample weight ± 2σ ± 2σ ± 2σ (ppm) (ppm) (ppb) (Ma) (Ma) (mg) TC18MVM001 50 6.835 0.020 4.296 0.013 124.20 0.10 1711 8 TC18MVM002 9 1.303 0.004 0.819 0.002 23.80 0.03 1719 8 FR18MVM001 20 1.180 0.003 0.742 0.002 21.49 0.02 1714 8 FR18MVM001RPT 33 2.134 0.006 1.342 0.004 38.86 0.04 1714 8 BW18MVM003 20 1.616 0.005 1.015 0.003 120.20 0.10 6713 30 BW18MVM003RPT 60 2.194 0.006 1.379 0.004 118.30 0.30 4940 24 BW18MVM006 26 2.258 0.007 1.420 0.004 42.66 0.10 1777 9
3 NTGS Record 2019-009 SAMPLES ANALYSED for the metasedimentary rocks that host mineralisation at Explorer 27. Chalcopyrite–molybdenite–pyrite-bearing quartz vein, The Explorer 27 prospect occurs close to vein-hosted, Explorer 27 prospect (TC18MVM001) alluvial, and eluvial gold mineralisation (Figure 3). The Last Hope gold deposit is located ~3 km (Yeaman 1969), and Sample information the Bull Pup gold deposit, ~3.6 km southeast of Explorer 27 (Tapp 1966). NTGS Sample ID: TC18MVM001 As the Explorer 27 prospect is located close to the Collector: Matt McGloin margin of monzonite, quartz monzonite, and quartz diorite 1:250 000 mapsheet: TENNANT CREEK (SE 53-14) intrusions, it is possible that the copper–molybdenum 1:100 000 mapsheet: Short Range (5659) mineralisation sampled in TC18MVM001 may have a Province: Warramunga Province similar age to the dated monzodiorite. Mineralisation at Grid reference: MGA94 Zone 53, 378009mE 7864932mN the prospect is hosted in quartz veins, unlike most copper (approximate position based on map of Tapp 1966) mineralisation in the Tennant Creek mineral field, which is Drillhole: DDH1 (EXP027, Bureau of Mineral Resources) typically associated with ironstone bodies (Yeaman 1969, Azimuth: 360° Donnellan 2013a and references therein). 40Ar/39Ar dating Declination: -60° of coarse white mica associated with ironstone-hosted Depth: 170.5 m (557’) gold–copper–bismuth mineralisation at four deposits of Lithology: chalcopyrite–molybdenite–pyrite-bearing the Tennant Creek mineral field has yielded re-calibrated quartz vein 40Ar/39Ar ages ranging from 1851 ± 11 Ma to 1847 ± 11 Ma Geochronology target: molybdenite
Interpreted model age summary
1711 ± 8 Ma
Sample details and lithological characteristics
Molybdenite was sampled from diamond drillhole DDH1 at 170.5 m downhole depth. DDH1 intersected mineralisation at the Explorer 27 prospect in central eastern Short Range, Tennant Creek mineral field. The sampled molybdenite was metamudstone hosted in a 2 cm-wide quartz vein along with chalcopyrite and pyrite (Figure 2). The quartz vein cuts a light grey to faint pink, foliated metamudstone rock. A thin selvedge of feldspar and chlorite occurs on the margins of the quartz quartz K-feldspar vein. Molybdenite is fine-grained, typically 1–2 mm vein selvedge diameter and disseminated within the quartz vein. It is spatially associated, and commonly occurs in clusters, with chalcopyrite and pyrite. DDH1 tested a gossanous limonite outcrop with anomalously high Cu and Mo surface geochemistry (Yeaman 1969). It was drilled to target mineralisation at depth after geochemical sampling over a geophysical anomaly at the Explorer 27 prospect yielded anomalous results for Cu (≤1500 ppm) and Mo (≤800 ppm; Yeaman 1969). At surface, exposures of limonite-bearing gossan molybdenite represent oxidised sulfide mineralisation. Only minor amounts of chalcopyrite, pyrite and molybdenite in quartz veins were intersected during drilling, so the drill core was pyrite not assayed (Yeaman 1969). The limonite gossans at Explorer 27 are now mapped as part of the Wundirgi Formation, a sequence of arenite, chalcopyrite siltstone, shale and tuff within the Ooradidgee Group (Donnellan 2001, Donnellan et al 2001; Figure 3). The Wundirgi Formation is intruded by sills and small plutons of monzonite, quartz monzonite and quartz diorite (Donnellan A18-510.ai 2001, Donnellan 2013a). SHRIMP U–Pb zircon dating Figure 2. Photograph of drill core from the Explorer 27 prospect of a sample of monzodiorite that intrudes the Wundirgi showing a mineralised molybdenite-bearing quartz vein (sample Formation near the Last Hope gold mine constrains a TC18MVM001) cross-cutting metamudstone. Quartz vein is minimum depositional age of 1821 ± 8 Ma (Compston 1995) ~ 2 cm wide.
NTGS Record 2019-009 4 N 376000mE 377000mE 378000mE 379000mE 380000mE 381000mE 382000mE 383000mE 384000mE 385000mE 7866000m N
360 DDH1, Explorer 27 7865000m N 7864000m N
Last Hope 7863000m
N Bull Pup 7862000m N
A18-554.ai
7861000m sandy soil unnamed dolerite gold deposit colluvium unnamed monzonite approximate location of DDH1 drillhole collar, Explorer 27 copper-molybdenum prospect alluvium Manga Mauda Member silcrete Wundirgi Formation elevation limonite gossan Brumbreu Formation river/creek track 012 km fault UTM AGD66 Figure 3. Geological map of the location of the Explorer 27 prospect (map adapted from Tapp 1966 and Donnellan 2001). (Fraser et al 2008, recalculated from Compston and The Re–Os isotopic data for this sample are reported in McDougall 1994). These ages are broadly consistent with Table 2. Pb model ages of ca 1855 –1835 Ma from lead-bearing ironstone-hosted mineralisation (Warren et al 1995). Dating Interpretation of result of molybdenite at Explorer 27 was carried out to constrain the timing of this atypical style of Cu–Mo mineralisation. The ca 1711 Ma model age for sample TC18MVM001 (Table 2) is interpreted to record the timing of copper– Model result molybdenum mineralisation at the Explorer 27 prospect. Further interpretation of this result is described after ID–NTIMS analysis of molybdenite from sample consideration of the results of sample TC18MVM002 from TC18MVM001 yielded a model age of 1711 ± 8 Ma (2σ). the same prospect (this Record).
Chalcopyrite–molybdenite–pyrite-bearing quartz vein, Interpreted model age summary Explorer 27 prospect (TC18MVM002) 1719 ± 8 Ma Sample information Sample details and lithological characteristics NTGS Sample ID: TC18MVM002 Collector: Matt McGloin Molybdenite was sampled from diamond drillhole DDH1 1:250 000 mapsheet: TENNANT CREEK (SE 53-14) at 175.3 m downhole depth. DDH1 (Figure 3) intersected 1:100 000 mapsheet: Short Range (5659) mineralisation at the Explorer 27 prospect in central Province: Warramunga Province eastern Short Range, Tennant Creek mineral field. DDH1 Grid reference: MGA94 Zone 53, 378009mE 7864932mN tested a gossanous limonite outcrop with anomalously (approximate position based on map of Tapp 1966) high Cu and Mo surface geochemistry (Yeaman 1969). Drillhole: DDH1 (EXP027, Bureau of Mineral Resources) The sampled molybdenite was hosted in a 0.6 cm-wide Azimuth: 360° quartz vein along with chalcopyrite, pyrite and minor Declination: -60° hematite mineralisation (Figure 4). The quartz vein Depth: 175.3 m (571’) obliquely cuts a light grey to faint pink, compositionally Lithology: chalcopyrite–molybdenite–pyrite-bearing layered metamudstone rock. A 0.1 cm-wide selvedge quartz vein of feldspar occurs on the margins of quartz veins. Geochronology target: molybdenite Molybdenite is fine-grained, typically 1–2 mm diameter
5 NTGS Record 2019-009 and disseminated within the quartz vein; it is commonly Navigator 6 and Orlando East yielded ages of ca 1660 Ma clustered with chalcopyrite and pyrite. (Skirrow et al in review). Together with the results from this Details on drilling, geology, mineralisation and existing study, these ages provide evidence for previously unknown age constraints for sample TC18MVM002 are summarised copper mineralising episodes in the Tennant Creek mineral in sample TC18MVM001 (this Record). Molybdenite sample field that are markedly younger than age estimates for TC18MVM002 was dated to confirm the timing of copper– ironstone related copper–gold–bismuth mineralisation molybdenum mineralisation at the Explorer 27 prospect, (see Compston and McDougall 1994, Warren et al 1995, and to verify the reproducibility of the molybdenite dating Fraser et al 2008, Donnellan 2013a). In addition, the new technique at the prospect by comparison with sample ages overlap with hydrothermal disturbances previously TC18MVM001. reported for the K – Ar system in hydrothermal muscovite and biotite at some ironstone-hosted copper-gold deposits Model result (ca 1790 –1710 Ma; see Compston and McDougall 1994). However, the magmatic source for this younger ID-NTIMS analysis of molybdenite from sample mineralisation and associated hydrothermal fluids is TC18MVM002 yielded a model age of 1719 ± 8 Ma (2σ). currently unrecognised in the area. The Re–Os isotopic data for this sample are reported in The new copper–molybdenum mineralisation ages Table 2. from the Explorer 27 prospect are also within uncertainty of ages obtained for tungsten and copper mineralisation in Interpretation of result the Davenport and Aileron provinces. This includes a new molybdenite model age from the Pioneer deposit in the The new ca 1719 Ma Re–Os model age for sample Hatches Creek tungsten field (see sample FR18MVM001, TC18MVM002 is within analytical uncertainty of the this Record, for details and further discussion on a possible ca 1711 Ma model age from sample TC18MVM001 regional-scale mineralising event at this time). (this Record). Both samples were collected from similar copper–molybdenum-bearing quartz veins in DDH1 from Explorer 27. This suggests that both veins formed together during the same process. A link between copper–molybdenum mineralisation and felsic intrusions at the Explorer 27 prospect is supported by the low Re concentrations (< 7 ppm) in the analysed molybdenite samples. These low Re concentrations are consistent with fluids sourced from metamudstone relatively evolved granites or by dehydration of mid-crustal metamorphic rocks (Berzina et al 2005, Stein 2006). Low Re concentrations commonly indicate an evolved source (ie not an intermediate porphyry that might contain 50 ppm Re in the molybdenite; Berzina et al 2005). The ca 1719–1711 Ma model ages are interpreted to chalcopyrite constrain an absolute timing for copper–molybdenum quartz mineralisation at Explorer 27. These results represent the vein first time that copper mineralisation of this age has been reported in the Tennant Creek mineral field. The new molybdenite ages are also consistent with previously reported geochronology from other copper- bearing deposits in the Tennant Creek mineral field. A whole rock Re–Os isochron of high-grade copper sulfide (chalcopyrite) at the Gecko deposit yielded a model age of 1665 ± 66 Ma (McInnes et al 2008). However, the significance of this age remains unclear given the large uncertainty range (Donnellan 2013a). This chalcopyrite model age is within uncertainty of the new copper mineralisation molybdenite ages from samples TC18MVM001 and TC18MVM002, A18-511.ai which supports the possibility of a younger copper-related Figure 4. Photograph of drill core from the Explorer 27 prospect mineralising episode in the region. Furthermore, recent showing a mineralised molybdenite-bearing quartz vein (sample SHRIMP U – Pb dating of monazite associated with non- TC18MVM002) cross-cutting metamudstone. Quartz vein is ironstone-related gold–copper–bismuth mineralisation at ~ 0.6 cm wide.
NTGS Record 2019-009 6 Molybdenite–scheelite–wolframite-bearing quartz can be clearly distinguished from quartz by its strong vein, Pioneer deposit (FR18MVM001) fluorescence. The scheelite is intimately associated with molybdenite (Figure 6c, d). The quartz veins in the Sample information mine dump rocks cross-cut mafic amphibolite. Minor sulfides (chalcopyrite, pyrite, bornite) and malachite NTGS Sample ID: FR18MVM001 were also observed with the tungsten and molybdenum Collector: Matt McGloin mineralisation. The quartz veins typically contained 1:250 000 mapsheet: FREW RIVER (SF 53-03) minor hematite and tourmaline with muscovite and 1:100 000 mapsheet: Hatches (5956) K-feldspar selvedges commonly well-developed on vein Province: Warramunga Province margins. Figure 5 shows the mine dump and the location Grid reference: MGA94 Zone 53, 518579mE 7692107mN of the Dempsey and Jensen lodes to the northwest. Lithology: molybdenite–scheelite–wolframite-bearing The Pioneer deposit is located in the north of the quartz vein Hatches Creek tungsten field (Figure 7). The deposit Geochronology target: molybdenite covers an area of about 500 m trending southwest– northeast (Ryan 1961). En-echelon, south dipping Interpreted model age summary mineralised quartz veins of ≤1 m width extend for 90 –165 m, striking east–northeast (Ryan 1961). Typical 1714 ± 8 Ma ore minerals are wolframite and scheelite, along with bismutite, chalcocite, azurite, malachite and limonite. In Sample details and lithological characteristics the primary zone, wolframite and scheelite are associated with molybdenite, native bismuth, bismuthinite, A molybdenite–scheelite–wolframite-bearing quartz tetrahedrite, pyrite and chalcopyrite (Ryan 1961). The vein was collected from a mine dump in surface quartz veins are also associated with mica, K-feldspar workings at the Dempsey and Jensen lodes in the western and minor epidote and tourmaline alteration. These part of the Pioneer deposit, Hatches Creek tungsten mineralised quartz veins intrude metasandstone and field (Figure 5, 6a, b). The sample location is 10 m metamudstone of the Hatches Creek Group, as well as southwest of the orbital track that surrounds the former discrete blocks of mafic amphibolite from the informally mine in south central Hatches (Figure 5). Sample named Pedlar gabbro (Ryan 1961; Donnellan in review). FR18MVM001 comprises coarse-grained molybdenite Minor hornfels alteration occurs on the margin of country associated with scheelite and wolframite within a quartz rocks with the veins. The veins typically also have mica vein (Figure 6c, d). Under ultraviolet light, the scheelite selvedges.
518500mE 518600mE 518700mE 518800mE
0 25 50 m 4°30'
GOVERNMENT BATTERY 336.8m
MAG TRUE
7692200mN 339.9m 4m 22.9cm PINK LODE 65° 339.9m 342.9m o 38cm N 12 LODE 30cm Manway 60° 56°,60° 4.6m 55° FAULT 59° Filled o 60° 38cm 6.1m 336.8m N 5 LODE Filled Filled 0.3m 60° 0.6m 88° 53° o 3.7m 2.4m 1 LODE o Filled 333.7m Filled N 342.9m N 2 LODE LARSEN 0.3m Della 3.7m 72° 0.6m 0.3m 60cm 55° Shaft ? XMAS LODE 60° 0.8m 1.5m 2.1m Filled East Shaft 342.9m 1.5m 50° DEMPSEY LODE 58° FAULT Underlay Filled 50° 55° 5.5m 62° McArthur Xmas Shaft JENSEN LODE 0.6m PIONEER 30cm 0.9m Shaft Campbells 339.9m Shaft 64° 0.9m PIONEER 0.9m 1.2m 62° BATTERY 8.2m Shaft 339.9m Filled 0.9m 6.1m 7.6m 3.7m Boundary 58° 45° Shaft
7692100mN 6.1m 30cm 7.3m 63° 336.8m 3m 10.1m 0.9m 60° 0.6m 64°
Filled A18-508.ai 15 cm reef, position accurate, showing HATCHES CREEK GROUP form lines, 3m interval. Datum - collar 70° 1115 width and depth sandstone, greywacke, some of McArthur Shaft, RL 340m reef, approximate position quartzite, siltstone surface workings, showing depth reef, concealed PEDLAR GABBRO underground workings geological boundary, position accurate gabbro, dolerite main shaft geological boundary, approximate position shaft geological boundary, position concealed sample location inclined shaft 88° fault, position accurate showing dip disused or inaccessible shaft fault, position approx dump fault, concealed track ? fault, inferred 56° strike and dip of bedding
Figure 5. Map of the local area and geology of the Pioneer deposit showing the sampled location FR18MVM001 to the west of the deposit. Figure modified from Ryan (1961).
7 NTGS Record 2019-009 a b c mine shaft
quartz quartz wolframite
wolframite
scheelite molybdenite scheelite molybdenite
d McArthur Shaft Figure 6. Photographs of sample and Dempsey and Jensen lodes location for FR18MVM001 from location of sample FR18MVM001 Della Shaft Campbells Shaft the Pioneer deposit, Hatches Creek tungsten field. a ( ) Molybdenite and scheelite intergrown within a quartz vein. Sample is ~5 cm wide. (b) Same image under ultraviolet light where scheelite fluoresces in a light purple colour. (c) Mine dump at the Pioneer deposit where the sampled molybdenite was collected. Geopick for scale. (d) View of the Pioneer tungsten mine workings from a distant hill. Photograph looks northeast with various shafts and lodes indicated. Four-wheel drive A18-509.ai for scale.
N 517500mE 520000mE 522500mE
1 MINERAL OCCURRENCE Colluvium 012 km 7692500m Pioneer 1 Pioneer W deposit Dolerite, gabbro deposit 2 Endurance W MGA94 Zone 53 2 Alluvium 3 3 Ricketty Kate W 20 4 Black Diamond W Endurance Sandstone Mbr 5 Bonanza W Warnes Sandstone Mbr 4 6 Green Diamond group W Kurinelli Sandstone 5 6 7 Treasure W 8 Hidden Treasure W Taragan Sandstone Frew River Fm 7690000mN 9 Next Treasure W 10 Masters Gully W Coulters Sandstone 11 Euro W Newlands Volcanics 12 White Diamond W 45 40 13 Hen and Chickens W Yeeradgi Sandstone 14 BXB W Granophyre 23 15 Rocky Ridge W Treasure Volcanics 16 Kangaroo group W 7 Abandoned mine 21 19 17 Hit or Miss W deposit 7687500mN 60 8 45 9 18 Silver Granites W Strike and dip of strata 19 Copper Show W Quartz vein 13 22 10 20 Unnamed 01889 Cu 11 Fault 14 21 Unnamed 01306 Cu 12 80 Sample location 16 15 22 Dooleys Nob W 17 23 Frenchmans Point W 19 18 A18-170.ai 7685000mN
Figure 7. Geology of the Hatches Creek tungsten field showing location of the Pioneer deposit and other mineral occurrences. Modified from Kruse and Maier (2010).
NTGS Record 2019-009 8 No direct dating of mineralisation or host rocks has been Model result undertaken at the Pioneer deposit. However, metasandstone hosting the deposit is interpreted as a correlative of the An ID–NTIMS analysis of molybdenite from sample Warnes Sandstone Member (Kurinelli Sandstone), which FR18MVM001 yielded a model age of 1714 ± 8 Ma (2σ). has a SHRIMP U–Pb zircon maximum depositional age A repeat analysis of this sample (FR18MVM001RPT) of 1837 ± 7 Ma (Claoué-Long et al 2008). The informally yielded an identical model age of 1714 ± 8 Ma (2σ). The named Last Hope dolerite, a correlative of the Pedlar Re–Os isotopic data for these samples are reported in gabbro (Donnellan in review), has a SHRIMP U–Pb zircon Table 2. age of 1811 ± 5 Ma, interpreted to record the timing of emplacement (Maidment et al 2006). The interpreted ages Interpretation of result of these host rocks suggests that tungsten mineralisation at the Pioneer deposit is likely younger than ca 1810 Ma. The Re–Os model age of 1714 Ma for the molybdenite Mineralisation in the Hatches Creek tungsten field has (and genetically associated tungsten mineralisation) at previously been related to felsic magmatism (eg Blake et al the Pioneer deposit is broadly consistent with previously 1987, Wyborn et al 1998, Fraser et al 2008); however, granite reported Ar–Ar ages, and slightly older than one Re – Os is not widely exposed in the tungsten field (Donnellan molybdenite age, for tungsten mineralisation in the 2013a). Fraser et al (2008) suggested a temporal and genetic Hatches Creek and the Wauchope tungsten fields (see link between regional tungsten mineralisation and the Fraser et al 2008, Donnellan 2013a,b; McGloin et al 2019). ca 1710 Ma Devils Suite based on Ar–Ar muscovite dating The new age, along with these previous age constraints, of tungsten-bearing quartz veins: coarse-grained muscovite support the interpretation of a direct mineralisation age for selvedges on the edge of wolframite-bearing quartz veins at this deposit; it suggests a broadly consistent mineralising the Bonanza, Green Diamond and Copper Show prospects episode across the Hatches Creek tungsten field at in the Hatches Creek tungsten field yielded 40Ar/39Ar ca 1720–1680 Ma. The low Re concentrations (≤2 ppm) plateau ages of 1701 ± 7 Ma, 1703 ± 7 Ma and 1697 ± 7 Ma from the Pioneer deposit molybdenite are consistent with respectively. These ages are within uncertainty of each magmatic–hydrothermal fluids sourced from relatively other, and are indistinguishable from muscovite sampled evolved felsic intrusions (Berzina et al 2005, Stein 2006). from the Devils Marble Granite, which yielded an 40Ar/39Ar Further afield, similar ages for copper and tungsten plateau age of 1699 ± 7 Ma. The Devils Marbles Granite mineralisation associated with felsic magmatism are also has a SHRIMP 207Pb/206Pb zircon age of 1711 ± 11 Ma, reported. The age of tungsten mineralisation in the interpreted to record the timing of magmatic crystallisation Hatches Creek tungsten field is consistent with the new (Page 1996a). molybdenite Re–Os model ages for copper-molybdenum Recent molybdenite dating in the Hatches Creek mineralisation at the Explorer 27 prospect in the Tennant tungsten field at the Hit or Miss tungsten deposit, ~10 km Creek mineral field (see samples TC18MVM001 and south of the Pioneer deposit, yielded two Re–Os model TC18MVM002 in this Record). Similar ages for tungsten ages of 1677 ± 10 Ma and 1602 ± 9 Ma from mineralised mineralisation are inferred at the Juggler prospect in veins (McGloin et al 2019). These ages were tentatively the Davenport Province (Stidolph et al 1988, Donnellan interpreted as mineralisation and/or remobilisation ages for 2013b). The vein-hosted Juggler prospect occurs within molybdenum and tungsten, and the associated bismuth and the ca 1720 Ma Elkedra Granite (Page 1996b). The new copper mineralisation at the deposit. The older of the two molybdenite ages from the Pioneer deposit are also Re–Os model ages is broadly consistent with the previously similar to ca 1730–1700 Ma ages reported for granite- discussed ages determined for tungsten mineralisation related, epigenetic copper and tungsten mineralisation and felsic intrusions in the Warramunga Province. The in the eastern Aileron Province at Molyhil, the Bonya geological significance of the younger Re–Os molybdenite Hills area and the Jervois mineral field (McGloin and age is uncertain (McGloin et al 2019). Weisheit in review). This temporal and genetic link may Re–Os molybdenite dating at the Pioneer deposit suggest a widespread tungsten and copper mineralising provides an opportunity to directly constrain the timing episode across central Australia towards the end of the of tungsten and sulfide mineralisation in the north of the Paleoproterozoic. It hints at an exploration target from Hatches Creek tungsten field. It also tests the validity of the fertile crustal-scale magmatism in the southern part of the Re – Os method for directly dating tungsten mineralising North Australian Craton during this period. Additional events in the region. work is needed to test this hypothesis.
9 NTGS Record 2019-009 Molybdenite–scheelite-bearing quartz vein, Hill of Sample details and lithological characteristics Leaders deposit (BW18MVM003) A molybdenite- and scheelite-bearing quartz vein was Sample information collected from a mine dump at surface workings at the Hill of Leaders deposit in the Mosquito Creek tungsten field. NTGS Sample ID: BW18MVM003 The sample site is located ~150 m west of a station track, Collector: Matt McGloin about 22 km north of Kurundi Cattle Station in central 1:250 000 mapsheet: BONNEY WELL (SF 53-02) Ooradidgee (Figure 8). 1:100 000 mapsheet: Ooradidgee (5857) The Mosquito Creek Tungsten field extends over about Province: Warramunga Province 2 km2 and comprises several prospects containing scheelite Grid reference: MGA94 Zone 53, 463087mE 7753693mN and wolframite hosted in quartz veins ≤30 cm wide and Lithology: molybdenite–scheelite-bearing mineralised ≤200 m long (Stewart et al 1986, Donnellan 2013a). The quartz vein quartz veins are typically hosted within north to north– Geochronology target: molybdenite west trending shear zones. Quartz–tourmaline–muscovite greisenised selvedges are commonly associated with the Interpreted model age summary veins. Molybdenite sample BW18MVM003 (Figure 10a) was collected from the Hill of Leaders mine, where the No geologically meaningful age yielded. majority of ore in the mineral field was mined.
460000mE 465000mE 470000mE
7760000mN
North Curtis
7755000mN
Hill of Leaders
7750000mN
012 km MGA94 Zone 53
A18-538.ai active channel deposits (gravel, sand, silt) road aeolian and residual deposits (sand, silt, clay, dunes) watercourse colluvium (gravel, sand, silt) dyke/vein Hill of Leaders Granite Ooradidgee Group
Figure 8. Geological map of the Mosquito Creek tungsten field showing sample location sites at the Hill of Leaders deposit (BW18MVM003) and the North Curtis (BW18MVM006) prospect. Map modified from Wyche and Simons (1987).
NTGS Record 2019-009 10 In sample BW18MVM003, coarse-grained molybdenite tungsten field. Greisenisation observed in the granite is associated with scheelite in a vug within a quartz vein may relate to late-stage evolved fluids exsolved from the (Figure 9a, b). Under ultraviolet light, scheelite (clearly Hills of Leaders Granite as it crystallised, suggesting distinguished from quartz by its strong fluorescence) that tungsten mineralisation formed during emplacement occurs intimately associated with molybdenite (Figure 9c). of this intrusion (Donnellan 2013a). Alternatively, the Along with tungsten and molybdenum mineralisation, tungsten mineralisation may be associated with a poorly other ore minerals noted in quartz veins at the mine dump or non-exposed younger granite intrusion that exsolved (Figure 9d) include sulfides (chalcopyrite, pyrite, bornite) ore-forming fluids that infiltrated pre-existing granite. and malachite (Figure 9e). Quartz veins typically contain Donnellan (2013a) reports geophysical data indicating a minor hematite and tourmaline with muscovite and sub-circular gravity low coincident with the Mosquito K-feldspar selvedges commonly well-developed on vein Creek tungsten field that may be related to the younger margins. ca 1710 Ma Devil’s Marbles Granite Suite. Furthermore, The tungsten workings are hosted within the Hill of Maidment et al (2006) report a lamprophyre dyke Leaders Granite, a porphyritic plagioclase, muscovite- outcropping in the Mosquito Creek field with a SHRIMP biotite granite (Figure 10a–b). The granite has been U–Pb zircon age of 1711 ± 2 Ma. The ages of these felsic U–Pb zircon SHRIMP dated at 1846 ± 3 Ma (Maidment intrusions are purportedly similar in age to tungsten et al 2006), which provides a maximum age for tungsten mineralisation elsewhere in the Warramunga Province (eg mineralisation at the workings. Some debate remains as Wauchope tungsten field, Hatches Creek tungsten field; to the timing of mineralisation in the Mosquito Creek see Fraser et al 2008 and Donnellan 2013).
a b
molybdenite molybdenite
scheelite scheelite
c d
molybdenite
scheelite
e f
malachite
A18-505.ai
Figure 9. Mineralisation and alteration at the Hill of Leaders deposit. (a) Quartz vein collected from the mine dump showing a vug containing molybdenite and scheelite (sample BW18MVM003). Vein is ~ 0.6 cm wide. (b) Close-up of the same magnified using a hand lens. (c) Molybdenite sample BW18MVM003 under ultraviolet light showing highly fluorescent scheelite associated with molybdenite. (d) The mine dump sampled for molybdenite next to a large trench and shaft. (e) Copper carbonate minerals including malachite associated with quartz veins. Hand sample is ~ 8 cm across (f) Example of highly muscovitised greisen granite in the mine workings that was altered during the tungsten mineralisation process. Hand sample is ~ 8 cm across.
11 NTGS Record 2019-009 a Molybdenite sample BW18MVM003 was collected location of mine dump sampled for BW18MVM003 to constrain the timing of tungsten mineralisation at the Hill of Leaders tungsten deposit, and to help resolve which locally mapped (or currently unknown) felsic intrusive phase may be the likely source for the tungsten mineralisation.
Model result
An initial ID–NTIMS analysis of molybdenite from sample BC18MVM003 yielded a Re–Os model age of 6713 ± 30 Ma (2σ). This impossible age result warranted b a repeat analysis (BC18MVM003RPT), which yielded another impossible and irreproducible Re–Os model age of 4940 ± 20 Ma (2σ). The Re–Os isotopic data for this sample are reported in Table 2.
Interpretation of result
The ages obtained from sample BC18MVM003 and repeat sample BC18MVM003RPT are geologically impossible and were not able to be reproduced. These ages are not considered to have any geological significance. The A18-505.ai reason for the failed result is unclear. The samples contain Figure 10. The Hill of Leaders Granite and Hill of Leaders deposit. anomalously high concentrations of radiogenic 187Os (a) Photograph of the Hill of Leaders deposit workings, showing the relative to the measured Re content. This suggests that the Hill of Leaders Granite, which hosts the tungsten mineralisation, in the foreground and the workings sampled for BW18MVM003 sampled molybdenite may have lost Re after formation. in the background. (b) Close-up of Hill of Leaders Granite. This Alternatively the sampled coarse-grained molybdenite megacrystic K-feldspar porphyritic granite is comprised of K‑feldspar, may have been strongly decoupled spatially with respect plagioclase, quartz, muscovite and biotite. Hammer for scale. to Re and 187Os distribution.
Molybdenite–scheelite–wolframite-bearing quartz with minor wolframite, scheelite, pyrite and chalcopyrite, vein, North Curtis prospect (BM18MVM006) as well as oxidised tungstite and secondary copper carbonate minerals including malachite (Figure 11a). Sample information Under ultraviolet light, scheelite is distinguished from quar tz by its strong fluorescence (Figure 11b). Tourmaline, NTGS Sample ID: BW18MVM006 muscovite and biotite are common alteration minerals Collector: Matt McGloin associated with the quartz veins. The sampled mine dump 1:250 000 mapsheet: BONNEY WELL (SF 53-02) (Figure 11c) is located 6 m north from a small working and 1:100 000 mapsheet: Ooradidgee (5857) shaft on a 50 cm wide vertical quartz vein (Figure 11d–e). Province: Warramunga Province This shaft is at least 7 m deep. The quartz vein is hosted Grid Reference: MGA94 Zone 53, 462172mE 7754674mN in greisenised Hill of Leaders Granite (Figure 11f–g). Lithology: molybdenite–scheelite–wolframite-bearing Several other small pits and workings occur close to the quartz vein sample site. Geochronology target: molybdenite Details on the geology, mineralisation and existing age constraints for sample BW18MVM006 and the Interpreted model age summary wider Mosquito Creek tungsten field are summarised for sample BW18MVM003 (this Record). Molybdenite 1777 ± 9 Ma sample BW18MVM006 was dated to confirm the timing of tungsten mineralisation at the North Curtis prospect. Sample details and lithological characteristics Model result Several small chips of molybdenite–scheelite–wolframite- bearing quartz vein were collected from a mine dump ID–NTIMS analysis of molybdenite from sample at surface workings at the North Curtis prospect in the BW18MVM006 yielded a Re–Os model age of 1777 ± 9 Ma Mosquito Creek tungsten field (Figure 8). The sample site (2σ). The Re–Os isotopic data for this sample is reported in is located ~55 m south of a station track, about 22 km north Table 2. of Kurundi Cattle Station in central Ooradidgee. In the sample, coarse-grained molybdenite is associated
NTGS Record 2019-009 12 a b
molybdenite
scheelite
c d
sample site
e f
North Curtis sample site
quartz vein g
A18-507.ai Figure 11. Mineralisation and geology from the North Curtis prospect, Mosquito Creek tungsten field. a( ) Molybdenite and scheelite- bearing quartz chips sampled for BW18MVM006 (vein fragments are ~ 1 cm across). (b) same quartz chips under ultraviolet light showing highly fluorescent scheelite. c ( ) Mine dump of mineralised quartz where sample BW18MVM006 was collected (rucksack for scale). (d) View of working and mine dump at North Curtis. (e) View of small shaft with vertical-trending quartz vein exploited for tungsten. (f) View of North Curtis site from southerly hill outcrop of Hill of Leaders Granite (four wheel drive for scale). (g) Close-up of Hill of Leaders Granite showing a megacrystic K-feldspar, porphyritic, two mica composition (hammer for scale).
Interpretation of result Re concentration in the analysed molybdenite (≤2 ppm) is consistent with an evolved felsic magmatic source, The ca 1777 Ma model age for molybdenite from sample supporting a link with granite intrusions (Berzina et al BW18MVM006 is tentatively interpreted to record the 2005, Stein 2006). However, this new age is significantly timing of tungsten mineralisation at the North Curtis younger than that of the ca 1846 Ma Hill of Leaders Granite, prospect in the Mosquito Creek tungsten field. The low which the mineralised quartz vein cross-cuts. Thus, these
13 NTGS Record 2019-009 new data permit two possible interpretations of the Re–Os Donnellan N, 2013a. Chapter 9: Warramunga Province: in molybdenite age. First, the ca 1777 age records the timing Ahmad M and Munson TJ (compilers). ‘Geology and of tungsten mineralisation associated with a period of felsic mineral resources of the Northern Territory’, Northern magmatism not currently recognised in the Mosquito Creek Territory Geological Survey, Special Publication 5. tungsten field. Second, the age may reflect remobilisation Donnellan N, 2013b. Chapter 10: Davenport Province: in if molybdenite was dissolved and reprecipitated by Ahmad M and Munson TJ (compilers). ‘Geology and hydrothermal fluids during metamorphism and/or fluid mineral resources of the Northern Territory’, Northern flow, a process that could reset or decouple the Re–Os ratios Territory Geological Survey, Special Publication 5. in the molybdenite. However, the high closure temperature Donnellan N, in review. Geochemistry and petrogenesis of Re–Os in molybdenite (≥550–800 ; Selby et al 2004) of Palaeoproterozoic mafic rocks in the Tennant makes the second scenario unlikely. Region, central Australia, and their palaeotectonic ℃ implications. Northern Territory Geological Survey, ACKNOWLEDGMENTS Record. Ferenczi PA and Ahmad M, 1996. Davenport Province Thanks to Jay Carter for field assistance, and to Darryl – 1:250 000 mineral deposit data series. Northern Stacey and Max Heckenberg for organising logistics for Territory Geological Survey, Darwin. this trip. We acknowledge helpful discussions with Roddy, Fraser GL, Hussey K and Compston DM, 2008. Timing of Brian and Esther at the Battery Hill in Tennant Creek and Palaeoproterozoic Au–Cu–Bi and W-mineralisation thank them for access to the legacy drill core repository in the Tennant Creek region, northern Australia: at Battery Hill, Tennant Creek. We also thank staff at the Improved constraints via intercalibration of 40Ar/39Ar Devil’s Marbles Hotel and Kurundi Cattle Station. Thanks and U–Pb ages. Precambrian Research 164(1), 50–65. as always to Kathy Johnston for figure preparation and Kruse PD and Maier RC, 2010. Frew River, Northern formatting, and to Jo Whelan for reviewing this Record. Territory (Third Edition). 1:250 000 geological map series, SF 53-03. Northern Territory Geological REFERENCES Survey, Darwin. Maidment DW, Lambeck A, Huston D and Donnellan N, Berzina AN, Sotnikov VI, Economou-Eliopoulos M 2006. New geochronological data from the Tennant and Eliopoulos DG, 2005. Distribution of rhenium Region: in ‘Annual Geoscience Exploration Seminar in molybdenite from porphyry Cu–Mo and Mo–Cu (AGES) 2006, Record of Abstracts’. Northern Territory deposits of Russia (Siberia) and Mongolia. Ore Geology Geological Survey, Record 2006–002, 32–35. Reviews 26, 91–113. Markey RJ, Stein HJ, Hannah JL, Selby D and Creaser RA, Blake DH, Stewart AJ, Sweet IP and Hone IG, 1987. 2007. Standardizing Re–Os geochronology: A new Geology of the Proterozoic Davenport province, central molybdenite Reference Material (Henderson, USA) Australia. Bureau of Mineral Resources, Australia, and the stoichiometry of Os salts. Chemical Geology Bulletin 226. 244, 74–87. Bingen B and Stein S, 2003. Molybdenite Re–Os dating McGloin MV, Huston DH and Norman M, 2019. Summary of biotite dehydration melting in the Rogaland high- of results. Re–Os molybdenite dating of the Hit or temperature granulites, S Norway. Earth and Planetary Miss tungsten deposit, Hatches Creek Tungsten field, Science Letters 208, 181–195. Warramunga Province. Northern Territory Geological Claoué-Long JC, Maidment D and Donnellan N, 2008. Survey, Record 2019-010. Stratigraphic timing constraints in the Davenport McGloin MV and Weisheit A, in review. Epigenetic Province, central Australia: A basis for Palaeoproterozoic copper and tungsten mineralisation in the Bonya Hills correlations. Precambrian Research 166(1–4), 204–218. and Jervois mineral field, eastern Aileron Province. Compston DM and McDougall I, 1994. 40Ar–39Ar and Northern Territory Geological Survey, Record. K – Ar age constraints on the Early Proterozoic Tennant McInnes BIA, Keays RR, Lambert DD, Hellstron J Creek Block, northern Australia, and the age of its and Allwood JS, 2008. Re–Os geochronology and gold deposits. Australian Journal of Earth Sciences 41, isotope systematics of the Tanami, Tennant Creek and 609 –616. Olympic Dam Cu–Au deposits. Australian Journal of Compston DM, 1995. Time constraints on the evolution of Earth Sciences 55, 967–981. the Tennant Creek Block, northern Australia: in Collins Norman M, Bennett V, Blevin P and McCulloch M, 2004. WL and Shaw RD (editors). ‘The time limits on tectonic New Re–Os ages of molybdenite from granite-related events and crustal evolution using geochronology: some deposits of eastern Australia using an improved multi- Australian examples’. Precambrian Research, Special collector ICPMS technique. Tectonics to Mineral Volume 71, 315–346. Discovery - Deconstructing the Lachlan Orogen. Donnellan N, 2001. Short Range, Northern Territory Proceedings volume and field guide, MORE-SGEG (First Edition). 1:100 000 geological map series, 5659. conference, Orange, NSW, Geological Society of Northern Territory Geological Survey, Darwin. Australia Abstracts 74, 129-132. Donnellan N, Hussey KJ and Morrison RS, 2001. Short Page RW, 1996a. GA sample 84497021 (Devils Marbles Range, Northern Territory (First Edition). 1:100 000 Granite). Geoscience Australia’s Geochron Delivery geological map series explanatory notes, 5659. Northern System.
NTGS Record 2019-009 14 Page RW, 1996b. GA sample 84497022 (Elkedra Granite). Stein HJ, 2006. Low-rhenium molybdenite by Geoscience Australia’s Geochron Delivery System. metamorphism in northern Sweden: Recognition,
15 NTGS Record 2019-009