Alkaline Rocks and Carbonatites of the World

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Wapikopa Lake

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Occurrence number: 
031-00-045
Country: 
Canada
Region: 
Ontario
Location: 
Longitude: -88, Latitude: 52.07

Wapikopa Lake is an elliptical complex covering 98 km2, intruded into Precambrian orthogneisses. It consists of a core of pyroxene syenite with an outer zone, best developed in the southeast, of a mafic pyroxene syenite. The mafic syenite consists of 25-70% augite/aegirine-augite in crystals up to 1 cm in length and sometimes rimmed by amphibole, perthite, up to 15% apatite, abundant sphene and a little quartz. The core syenites are mineralogically similar but with only 5-35% pyroxene. Dykes of amphibole syenite occur on the northwestern margin of the complex. The syenites are highly potassic and BaO values approach 1.5%.

Age: 
K-Ar gave 2534+-147 Ma (Bell and Watkinson, unpublished data, quoted by Sage, 1983a, p. 5).
References: 
SAGE, R.P. 1983a. Geology of the Wapikopa Lake alkalic rock complex. Open File Report, Ontario Geological Survey, 5419: 1-82
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith