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King, Erayinia |
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Western Australia, WA, Australia |
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Zn Ag Au Pb
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The King or Erayinia VHMS (volcanic hosted massive sulphide) deposit is located ~140 km ESE of Kalgoorlie, within the Kurnalpi Terrane of the Yilgarn Craton, near it's southeastern margin with the Albany-Fraser Orogen, south-west Western Australia.
Exploration undertaken by Sons of Gwalia Ltd during the early to mid-1990's identified indications of VHMS mineralisation within the area, which is characterised by limited outcrop and deep weathering.
An extensive aircore (AC) and reverse circulation (RC) drilling and sampling campaign subsequently established the regional stratigraphy, intersected further VHMS-style mineralisation, and delineated the King deposit. Indications of mineralisation are distributed over a north-south strike length of ~35 to 40 km. This included the King North Prospect, ~2.5 km to the ENE of the main King deposit. Between 2012 and 2023, a further extensive program of soil and rock-chip geochemistry was executed across the Erayinia area, as well as a heliborne VTEM (Versatile Time Domain EM) geophysical survey, which was flown in 2013, identifying 24 targets. In late 2018, 10 060 line km of high-resolution regional airborne magnetics were flown, at 37 m sensor height and 50 m line spacing, to enhance geological mapping and facilitate regional correlations of the VHMS-favourable stratigraphy. This was complimented by extensive regional AC, RAB (Rotary Air Blast) and RC drilling to aid in re-mapping of the greenstone belt.
The latter had been delineated by 2007's, but as of 2025 has not been exploited.
The Yilgarn Craton records a history of crustal growth extending from ~4.4 to 2.6 Ga, and is composed of generally NNW-SSE trending Archaean granite-greenstone terranes that may be subdivided into a series of domains based on distinct lithological associations, geochemistry, and ages of volcanism. The Kurnalpi Terrane is characterised by 2.72 to 2.70 Ga mafic calc-alkaline volcanic complexes (including abundant intermediate rocks) with thin interlayered komatiites. Between 2692 and 2680 Ma, volcanic centres in the Kurnalpi Terrane were associated with largely bimodal (basalt-rhyolite) volcanic and associated sedimentary rocks. As detailed above, the Erayinia region is located ~100 km ESE of Kalgoorlie, towards the SE margin of the Kurnalpi Terrane, and is composed of three major domains, as recognised by the Geological Survey of Western Australia (GSWA) mapping, namely Menangina, Murrin and Edjudina. Of these, only the latter is represented in the immediate Edjudina area.
The 300 km long, north-south trending Edjudina Domain, occupies the longitudinal core of the southern half of the Kurnalpi Terrane. Within the Kurnalpi Terrane, it is bounded to the east by the Linden Domain, and to the west, progressively by the Murrin Domain across the Claypan Fault, and then across the Roe Hills Fault, by the Menangina Domain.
The Edjudina Domain is characterised by tholeiitic basalt, calc-alkaline andesitic volcanic complexes, and minor komatiite (Swager, 1995). These rocks are overlain by a laterally extensive belt of epiclastic units that are interbedded with banded iron formation (BIF), chert and slate, which were subsequently intruded by dolerite sills and dykes (Swager, 1997). Available U-Pb zircon ages within this suite are rare, but include 2708 ±6 and 2698 ± 10 Ma respectively from a metadacite within a felsic sequence associated with a calc-alkaline suite, and from a metatonalite, both from ~100 km north of King deposit. A third date is 2680 ±4 Ma from a granite gneiss, 30 km NE of King (Wingate, et al., 2016).
In the immediate Erayinia area, the Edjudina Domain is predominantly composed of bimodal basaltic-rhyolitic volcanic complexes and extensive dolerite sills and dykes (Swager 1995, 1997). Several metasedimentary units are also intercalated within the sequence, including metamorphosed chert, overlain by banded iron formations. The stratigraphic sequence, as detailed below is as described by Hollis et al., (2019) and modified by Kelly et al., 2024).
The host sequence and contained King deposit is overturned and east dipping, with the sequence below described from the stratigraphic footwall to hanging wall, or structural hanging wall to footwall. To the east of the King deposit and King North prospect, the lower units of the Edjudina Domain sequence are underlain by undifferentiated schists and gneisses, whilst to the east, a faulted arm of the same host units are intruded by a late regional granitoid mass.
• Footwall Mafic units, the oldest lithologies of the footwall sequence, dominated by ~250 m of strongly foliated package of biotite-muscovite schist, interpreted to represent a mafic-derived metasedimentary protolith, on the basis of the abundance of muscovite and biotite, high Al2O3 content, and its immobile element ratios (e.g. low Zr/TiO3; Hollis et al., 2019; Kelly et al., 2024). This unit is overlain by >300 m of foliated garnet amphibolite, interpreted to represent a sheared and metamorphosed package of tholeiitic mafic rocks (Hollis et al., 2019; Kelly et al., 2024). The garnet amphibolite is dominated locally by intense chlorite ±magnetite ±ilmenite alteration, occurring as magnetite-chlorite schist, where cut by stringer pyrite- chalcopyrite-pyrrhotite mineralisation.
• Footwall Intermediate to Felsic units, which overlie the Footwall Mafic units package, occurring as a 80 to 200 m thick mixed sequence of intermediate to felsic schist, dominantly chlorite-muscovite-quartz schist, with lesser muscovite-chlorite schist (Hollis et al., 2019). On the basis of their mineralogy (e.g. abundance of quartz and muscovite) and immobile element geochemical characteristics (e.g. high Zr/Ti and Th/Yb, gently dipping chondrite-normalised REE profiles with negative Eu anomalies), the protoliths of all of these units are interpreted to be calc-alkaline dacitic-rhyolitic volcanic/volcaniclastic rocks (Hollis et al., 2019; Kelly et al., 2024). Felsic rocks from this package immediately underlying the massive sulphides, are dominated by intense quartz-sericite alteration and become more chloritic towards the contact with the stratigraphically underlying mafic units. A narrow zone of intense Mg-rich chlorite alteration also occurs below the quartz-sericite zone and is represented by a package of muscovite-chlorite schist, also informally referred to as ‘talc schist’ (Dana et al., 2025). This latter schist is interpreted to represent intensely metasomatised intermediate to felsic volcanic rocks. Relatively thin, but uncommon, bands of graphitic schist are also found in the footwall stratigraphy. Stringer sulphide mineralisation at King occurs as locally intense zones of pyrite (sphalerite) and pyrrhotite-pyrite (-chalcopyrite) veining throughout footwall lithologies, which are recrystallized into the regional foliation.
• Massive Sulphide Mineralisation, which at King is dominated by iron sulphides, and occurs as a 1 to 7 m thick, broadly concordant lens of pyrite-pyrrhotite-sphalerite at the contact between the felsic muscovite-quartz schists and a thin unit of amphibole-quartz schist. The latter is also referred to as the 'grunerite-BIF' by Hollis et al. (2019, and has been interpreted as a metamorphosed 'exhalite' (e.g., Kelly et al., 2024); see below. The massive sulphides are recrystallised pyrite and pyrrhotite, with lesser sphalerite and chalcopyrite filling interstitial spaces, as well as trace marcasite, galena and some Sb-bearing minerals (e.g. gudmundite - FeSbS, ullmannite - NiSbS, and boulangerite - Pb5Sb4S3. One of the best intersections from King has been 8 m @ 6.7% Zn, 0.4% Pb and 23 g/t Ag.
At King North, the primary sulphide assemblage is dominated by pyrite, sphalerite, chalcopyrite, pyrrhotite and galena, which are distributed throughout the footwall lithologies, occurring as disseminated grains and as stringer veins recrystallised into the regional foliation. The sulphide assemblage grades stratigraphically upwards from being dominated by pyrite-chalcopyrite-pyrrhotite in the garnet amphibolite, to increased abundances of sphalerite, galena and lesser chalcopyrite in more felsic lithologies.
Stratigraphically beneath the massive sulphide lens at King, a zone of discordant vein and disseminated sulphides, dominated by pyrite, chalcopyrite and pyrrhotite is evident, recrystallised into the regional foliation. The stringer mineralisation becomes increasingly sphalerite rich closer to the massive sulphide lens, but is chalcopyrite-rich in the deeper, more distal mafic footwall stratigraphy.
A diverse variety of tellurides also occur within the stringer zone within the footwall garnet amphibolite). Gold grades are variable across the deposit, with the best intersection being 5 m @ 0.6 g/t Au in the massive sulphide lens. Secondary Cu-minerals, predominantly malachite, are the most dominant components near surface, most likely remobilised from the underlying Cu-bearing chloritic stockwork (Hollis et al., 2019).
• Mixed Hanging-wall Package - The overlying hanging-wall lithologies are dominantly argillaceous meta-sedimentary, and intermediate to felsic meta-volcaniclastic rocks, with thin (a few metres or less) intercalated units of amphibolite. The massive sulphide lens and related mineralisation of the King VHMS deposit is immediately overlain by a narrow horizon of amphibole-quartz schist, which, as noted above, is interpreted to be a metamorphosed 'exhalite' layer. This interpretation is based on it's high iron contents (>25% Fe2O3); anomalous high magnetic susceptibility; and a unique texture, characterised by banded grunerite-quartz rich layers (Kelly et al., 2024). Overlying volcanic rocks are dominated by mafic (garnet-amphibole) to felsic (calcite-muscovite-quartz) schists (Hollis et al., 2019). Rare units of graphitic schist and quartz-porphyroblastic felsic schist are also found in the upper stratigraphic levels of the hanging wall sequence. The hanging wall garnet amphibolite has a similar mineralogy with those in the footwall, but it's immobile geochemistry suggests it has a calc-alkaline basaltic-andesitic affinity (Hollis et al., 2019; Kelly et al., 2024). The calcite-muscovite-quartz schist, which is interpreted to represent intermediate-derived meta-sedimentary protoliths due to the abundance of quartz, mica and carbonate, preserves graded bedding and laminations (Hollis et al., 2019; Kelly et al., 2024). These hanging-wall units, which are up to several hundred metres thick, are relatively unaltered, although minor secondary chlorite-carbonate is evident. The whole stratigraphic sequence at King has been intruded by at least two generations of quartz-feldspar porphyry sills, and late-stage E-W and NNE-SSW oriented dolerite dykes (Hollis et al., 2019).
• Colby Schists and BIF Package - which, while part of the Edjudina Domain are thrust with an east vergence over the Erayinia sequence detailed above. These lithologies are comprise a poorly defined, mixed sequence of basalts, undifferentiated schists and metasediments, with intercalated BIF units, and are exposed over a width of ~200 to 700 m to the east of the Claypan Fault. In that width they are folded into a north-south anticline and syncline.
• Erayinia NW Package, which occupies a 600 m to 2.5 km wide slice of the eastern Murrin Domain and lies to the west of the Claypan, which separates it from the Edjudina Domain. It is predominantly composed of basalt to felsic volcanic/volcaniclastic rocks with interbedded black shale, and intercalated magnetic amphibolite.
• Upper Package of the Murrin Domain, which has been thrust to the east over the Erayinia NW Package, and is composed of basaltic to felsic volcanic/volcaniclastic rocks that are interbedded with siltstone and black shale.
The Colby, Erayinia NW and Upper Package of the Murrin Domain have all been intruded by granitoids, predominantly quartz porphyritic monzonite that predates the Claypan and thrust network that were folded prior to faulting.
Hollis et al. (2019) note that hydrothermal alteration in stratigraphically overlying intermediate to felsic rocks is characterised by a mineral assemblage of quartz-muscovite ±chlorite ±albite ±carbonate. Cordierite and anthophyllite are locally significant and indicative of zones of Mg-metasomatism prior to metamorphism. Increases in SiO2, Fe2O3T, pathfinder elements (e.g. As, Sb, Tl), and depletions of Na2O, CaO, Sr and MgO occur in quartz-muscovite schists approaching massive sulphide mineralisation. Within all strata (including the immediate hanging wall), the following pathfinder elements are strongly correlated with Zn: Ag, As, Au, Bi, Cd, Eu/Eu*, Hg, In, Ni, Pb, Sb, Se and Tl.
The main King deposit has a strike length of ~1.2 km and persists down a 70°E dip for at least 600 m. It lies ~350 m east of, and sub-parallel to, the north-south trending, major domain bounding Claypan Fault, and tapers south to within a few hundred metres north of the intersection of that structure with the NE-SW to NNE-SSW trending Maverick Fault. Another branch of the same mineralised sequence is located to the SE of this latter structure, apparently displaced with the same west facing, but with little or no significant mineralisation. These two west facing limbs form a V shape, bisected by the Maverick Fault. The King deposit, which lies on the western limb of this V-shaped structure, is truncated to the south by the Maverick Fault, and is fault offset by ~1 km in a dextral sense on its northern end by the parallel King Fault. It reappears on the northern side of the King Fault to form the King North prospect, with weaker mineralisation distributed over an ~3km strike length.
Non-JORC compliant resource estimates at the King deposit, as quoted by Hollis et al. (2019) are:
2.15 Mt @ 3.47% Zn, 0.3% Pb, 15 g/t Ag, 0.2 g/t Au.
The most recent source geological information used to prepare this description was dated: 2025.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Dana, C.D.P., Hollis, S.P., Podmore, D., James, M. and Azri., R., 2025 - Using coupled bulk-rock geochemistry and short-wave infrared (SWIR) spectral reflectance data as rapid exploration tools in metamorphosed VHMS deposits: insights from the King Zn deposit, Yilgarn Craton, Western Australia: in Mineralium Deposita v.60., pp. 1117-1140, doi.org/10.1007/s00126-024-01342-8
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Hollis, S. P., Podmore, D., James, M., Menuge, J. F., Doran, A. L., Yeats, C. J. and Wyche, S. 2019 - VHMS mineralisation at Erayinia in the Eastern Goldfields Superterrane: Geology and geochemistry of the metamorphosed King Zn deposit: in Australian J. of Earth Sciences v.66, pp. 153-181. doi.org/10.1080/08120099.2018.1515577
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Kelly, J., Hollis, S.P., Dana, C.D.P., Kneeshaw, A., Podmore, D., James, M., Azri, R., Rodgers, C.and Roberts, S., 2024 - Characterization of a Metamorphosed Volcanic Stratigraphy and VMS Alteration Halos Using Rock Chip Petrography and Lithogeochemistry: A Case Study from King North, Yilgarn Craton, Western Australia: in Minerals (MDPI) v14, 30p. doi.org/ 10.3390/min14050481
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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