Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Cabonga Reservoir

stripes

Occurrence number: 
031-00-104
Country: 
Canada
Region: 
Quebec
Location: 
Longitude: -76.48, Latitude: 47.18
Carbonatite: 
No

A small crescentic mass of nepheline syenite outcrops 1 km south of Nadon Bay on the southern side of Cabonga Reservoir. Enveloped in Precambrian gneisses and amphibolites, the rock consists of plagioclase, nepheline, biotite, muscovite and corundum, with sodalite apparent in hand speciments.

Age: 
K-Ar on biotite gave 894 Ma (MacIntyre et al., 1969), but this is probably only dating a metamorphic event.
References: 

LAURIN, A.F. 1960. Preliminary report on Tubquetil-Emard area Pontiac Electoral District. Preliminary Report, Quebec Department of Natural Resources, 424: 1-9.
MACINTYRE, R.M., YORK, D. and GITTINS, J. 1969. The K-Ar characteristics of nepheline. Earth and Planetary Science Letters, 7: 125-31.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith