Alkaline Rocks and Carbonatites of the World

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Venturi Township (Township 107, Spanish River)

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Occurrence number: 
031-00-077
Country: 
Canada
Region: 
Ontario
Location: 
Longitude: -81.07, Latitude: 46.05

A body of carbonatite at least 1.2 km long and 200 m wide strikes northeast and dips to the southeast, but its full extent is obscured by swamp and drift, although it certainly extends into Township 108 to the north. The body cuts Precambrian granite gneisses and is itself dissected by mafic dykes. The carbonatite is dolomitic, strongly foliated, and brecciated with abundant phlogopite. Vermiculite is present and apparently formed by the alteration of the dykes. An extensive fenite aureole including sodic amphibole-rich types has been detected by drilling (J.Gittins, personal communication and P. Mainwaring - quoted in Currie, 1976a, p. 132).

Economic: 
Has been investigated extensively as a vermiculite prospect.
Age: 
K-Ar on mica gave 1560 Ma (Gittins et al., 1967).
References: 
CURRIE, K.L. 1976a. The alkaline rocks of Canada. Bulletin, Geological Survey of Canada, 239: 1-228. J.Gittins, personal communication, 1976. GITTINS, J., MACINTYRE, R.M. and YORK, D. 1967. The ages of carbonatite complexes in eastern Canada. Canadian Journal of Earth Sciences, 4: 651-5. GUILLET, G.R. 1962. Vermiculite in Ontario. Industrial Mineral Report, Ontario Department of Mines, 7: 1-39
Fig. 40 Venturi Township (after Guillet, 1962, Fig. 4a).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith