Onedin prospect (Gordon Downs 1), Koongie Park Community, Halls Creek Shire, Western Australia, Australia
Latitude & Longitude (WGS84): | 18° 19' 16'' South , 127° 32' 26'' East |
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Latitude & Longitude (decimal): | -18.32126,127.54075 |
GeoHash: | G#: qudxy28qf |
Locality type: | Prospect |
KΓΆppen climate type: | BSh : Hot semi-arid (steppe) climate |
Carbonate-associated base metal mineralisation (sub-basin floor replacement VHMS deposit).
Note on the mineral list: Orth (2002) also mentions minor silver minerals.
Described as the second largest prospect in the Koongie Park area after the Sandiego prospect. A VHMS deposit showing zinc and minor lead and copper. There are two units at the Onedin prospect. The lower unit in the northern and western areas of the prospect is composed of tholeiitic basalt, turbidites,hemipelagic mudstone,chert and some ironstone with rhyolite bearing breccias. The upper unit is a diverse collection of a coarse grained sediment interbedded with turbidites, hemipelagic mudstone, volcaniclastic quartz bearing units with siliceous sandstone and mudstone, intruded by rhyolite, tholeiitic dolerite and late tholeiitic basalt dykes.
The footwall is a quartz bearing mudstone with chlorite-quartz-white mica. The host is a sequence of mudstone, sandstone, chert and ironstone with abundant Mg, Si and Ca in carbonate, talc, chlorite, quartz, and white mica. The hanging wall is quartz-albite, partially replaced by phyllosilicate minerals.
The sulphide is hosted by carbonate or chlorite schist, with zinc rich massive sulphide of sphalerite, pyrrhotite, chalcopyrite and pyrite, with minor galena and silver minerals, in two 10-60 metre thick carbonate lenses. Massive, vein and disseminated sulphides are hosted in chlorite schist between and above the lenses.
The carbonate (dolomite and ferroan dolomite) has caused an increase of Ph of the metal bearing fluid, thereby precipitating sulfide minerals. The carbonate alteration is complex with 13 different petrographic carbonate types forming 8 carbonate facies via diagenesis, hydrothermal alteration, mineralisation, deformation and metamorphism. The deposit was formed in a deep water environment with high levels of intrusion and extension. The local intrusions of rhyolitic sills resulted in lithification of the surrounding sediment and increasing the temperature, generating fluid circulation, and confining the fluid flow beneath a cap. The circulation in porous volcaniclastic sediment and the host sequence resulted in lower Na levels, and the precipitation of chlorite, quartz, muscovite, carbonate and talc. The carbonate was upgraded by alteration providing a trap to deposit the base metal sulfide minerals.
Mineral List
16 valid minerals.
Rock Types Recorded
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Alphabetical List Tree DiagramRegional Geology
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
Paleoproterozoic 1600 - 2500 Ma ID: 3186269 | Paleoproterozoic sedimentary rocks Age: Proterozoic (1600 - 2500 Ma) Comments: Arunta Block Lithology: Sedimentary rocks 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. [154] |
Orosirian 1800 - 2050 Ma ID: 834874 | Koongie Park Formation Age: Orosirian (1800 - 2050 Ma) Stratigraphic Name: Koongie Park Formation Description: Metamorphosed felsic volcanic and volcaniclastic rocks, metasedimentary rocks, metabasalt, and hornfels; locally migmatitic; minor chert, banded iron-formation, and carbonate; locally intimately veined by granitic rocks and gabbro Comments: igneous felsic volcanic; metasedimentary; synthesis of multiple published descriptions Lithology: Igneous felsic volcanic; metasedimentary 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). [5] |
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