Wandagee Diamond Province, Wandagee Station, Carnarvon Shire, Western Australia, Australiai

Regional Level Types
Wandagee Diamond Province	Province
Wandagee Station	- not defined -
Carnarvon Shire	Shire
Western Australia	State
Australia	Country

Located 125 kilometres north-east of Carnarvon.

First discovered in 1975 by CRA, so far 16 small kimberlite-like diatremes, and 6 dykes and sills have been found, in a belt 50 kilometres long by 15 kilometres wide, at the north-eastern edge of the Southern Carnarvon basin.

Later, Stockdale Prospecting Limited discovered a further 6 bodies. While one sill is exposed along the banks of the Minilya River, the others are concealed beneath soil or Cretaceous sediments.

The diatremes are carrot shaped vents, steep sided, filled with poorly bedded tuff and tuff breccia. The surface areas range from 1 to 14 ha. Sills and dykes, 1 to 15 metres thick, consisting of porphyritic olivine rich monchiquite (olivine lamproite).

The diatremes are associated with the Wandagee Fault Zone, and the east boundary of the Yanrey-Wandagee Ridge. Four of the bodies are concealed under sediments 158 metres thick.

The sills and dykes are dark porphyritic magmatic rocks containing 30-60% olivine phenocrysts, and rare macrocrysts of olivine up to 8mms across. The groundmass is abundant green diopside laths, with chromium spinal granules with biotite and kaersutite, with patches of calcite, alkali feldspar, and anaclime.

The pyroclastics of the diatremes consist of extensively altered tuffs, lapilli tuffs, and tuff breccia, coarse ash, fine lapilli with quartz grains, shale fragments, siltstone and sandstone. The fragments have cores of olivine altered to serpentine, and sometime carbonate, surrounded by a thin selvedge of fine grained magmatic material. Chromian diopside, chrome pyrope and three small diamonds have also been found.

Map denotes Wandagee pastoral station homestead location.

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