Alkaline Rocks and Carbonatites of the World

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Masson Street


Occurrence number: 
Montreal area
Longitude: -73.05, Latitude: 45.05

This sill outcrops in the Longue Pointe area of the City of Montreal and extends over about 2.5 km in a north-northwest- south-southeast direction with a width of some 500 m. Other sill outcrops occur within the city further to the north-northwest. About 8 m thick the sill is a tinguaite with phenocrysts of aegirine, nepheline, hauyne and orthoclase in a syenitic matrix.

Formerly quarried for road metal, but not now worked.
CLARK, T.H. 1952. Montreal area Laval and Lachine map-areas. Geological Report, Quebec Department of Mines, 46: 1-159
Fig. 61 Distribution of alkaline rocks in the area of Montreal.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith