Alkaline Rocks and Carbonatites of the World

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Cargill

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Occurrence number: 
031-00-067
Country: 
Canada
Region: 
Ontario
Location: 
Longitude: -82.07, Latitude: 49.02

This complex is intruded into Precambrian granite gneisses and quartz gabbros. Outcrop is scarce but there is a strong, double aeromagnetic anomaly. There is a variety of ultramafic rocks, many showing layering, and including olivine and hornblende pyroxenite and hornblendite, all with variable Ti-magnetite and abundant sphene. These are cut by late segregation veins rich in aegirine. Carbonatites cut the ultramafic rocks. In the western part they form a plug-like body and comprise calcite and dolomitic carbonatites with apatite, richterite to arfvedsonite, phlogopite, olivine and titaniferous clinohumite. Pyrochlore has not been reported. The eastern part has apatite- dolomite carbonatite. There has been deep erosion, probably by karst development and collapse, producing an extensive depression about 200 m deep, which is filled with lacustrine sediments overlying a residual layer rich in apatite. Pollen as old as Cretaceous has been identified in the sediments.

Economic: 
Extensive drilling has proved a large tonnage of apatite, and is likely to be developed as an apatite mine.
Age: 
K-Ar on biotite gave 1740 Ma (Gittins et al., 1967).
References: 
BENNETT, G., BROWN, D.D., GEORGE, P.T. and LEAHY, E.J. 1967. Operation Kapuskasing. Miscellaneous Paper, Ontario Department of Mines, 10: 1-98. J. Gittins, personal communication, 1984. 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
Fig. 33 Cargill (after Bennett et al., 1967, Fig. 13).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith