|Latitude & Longitude (WGS84):||28° 33' 16'' South , 122° 28' 42'' East|
|Latitude & Longitude (decimal):||-28.55472,122.47856|
|Köppen climate type:||BWh : Hot deserts climate|
Location: 11 km north-east of the town of Laverton.
Admiral Hill contains copper, gold, and is possibly a VHMS deposit. In recent times an open pit was developed for the gold. Prior to 1989 Admiral Hill had produced 672 ounces of gold.
Admiral Hill has a deeply leached regolith with abundant kaolin. A syenite intrusion outcrops to the east close to the mineralisation. To the west of the syenite is calc-alkaline units with felsic to intermediate schists altered from volcaniclastic sediments, dipping 50 to 60 degrees east. The Footwall west of these units is mafic and ultramafic schist.
Copper and gold is associated, although copper in the regolith is more mobile, and separate to a degree. The main part of the deposit is a supergene zone immediately beneath the andalusite schist ridge, with gold found sporadically through leached kaolinite rock. The copper is mainly malachite and chalcocite in the base of the supergene zone, with gold more widespread in refractory quartz veins. Copper can be up to 10% and gold 70 g/t in rich patches, but is generally lower grades, with 0.5 g/t common. Malachite shows in the Admiral Pit walls as olive green staining, and malachite rock chips. Whether specimen grade material exists is uncertain.
Near the base of the oxidised zone is also narrow areas of copper and gold. Primary copper and gold is chalcopyrite and pyrite in veins, in a 5 to 30 metres wide zone in the Hanging Wall. Copper tends to form narrower zones within a broad low grade gold area. Copper is associated with chalcopyrite, pyrite and magnetite. An area of elevated copper called the Curry Copper Deposit is found below the Admiral Hill deposit.
Both are associated with sub-ecomonic levels of Ag, W, Mo, and Bi, with sporadic grains of molybdenite. There is some Zn, As, Sb, and Pb anomalism in envelopes surrounding the Cu-Au mineralisation, some La and Ce carbonate veins with elevated Ba, Sr and Pb. Isolated galena grains appear in some veins. REE is mainly allanite.
Focus Minerals claims strong evidence of a VHMS deposit at Admiral Hill from a 2015 drilling campaign. It notes a hematitic banded barite-calcite-dolomite zone with strong barium and manganese values, and elevated bismuth, strontium, copper, thorium, and yttrium in the banded zone. There is also light and heavy REE of the lanthanide series 10 times higher than the background. Overlying the copper supergene zone is elevated values of sulphur, gold, silver, arsenic, bismuth, molybdenite, and cadmium.
19 valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
2500 - 4000 Ma
|felsic volcanic and volcaniclastic rocks 74288|
Age: Archean (2500 - 4000 Ma)
Description: Quartz-feldspar (meta-) porphyry, porphyritic microgranite; rhyolite, dacite, rhyodacite, andesite; agglomerate, breccia tuff; felsic schist; felsic volcanic and volcaniclastic rocks; dacite and rhyodacite tuff; dacite porphyry;
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia). 
|Neoarchean - Mesoarchean|
2500 - 3200 Ma
|Archean volcanic and intrusive rocks|
Age: Archean (2500 - 3200 Ma)
Comments: Yilgarn Craton
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.