Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: a digital alkaline rocks and carbonatites database



Occurrence number: 
Montreal area
Longitude: -74.12, Latitude: 45.43

The Como pipe outcrops as a low mound of appoximately 200x500 m. The rock is a monticellite alnoite with phenocrysts of poikilitic phlogopite, monticellite and augite in a matrix of melilite, phlogopite, monticellite and calcite with accessory opaques, perovskite and apatite. A full petrographic description and whole rock analyses will be found in Howard (1922, p. 54). A smaller alnoite lies about 1 km to the east-southeast.

GOLD, D.P. and MARCHAND, M. 1969. The diatreme breccia pipes and dykes, and the related alnoite, kimberlite and carbonatite intrusions occurring in the Montreal and Oka areas, P.Q. Part 1: The alnoite, kimberlite, and diatreme breccia pipes and dykes. In Geology of the Monteregian Hills (Ed. G. Pouliot). Geological Association of Canada - Mineralogical Association of Canada, Guidebook: 5-42. HOWARD, W.V. 1922. Some outliers of the Monteregian Hills. Transactions of the Royal Society of Canada, Series 3, 16: 47-95.
Fig. 1_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