Troquoi

A number of syenite and quartz syenite intrusions of an alkaline character are described as of ‘Mont Troquoi type’ (Papon, 1973). Six such intrusions, all emplaced in Precambrian gneiss or migmatite, are indicated on the 1:500,000 geological map accompanying Papon’s (1973) paper. Three comprise the Mont Troquoi massif, each of which is two to four kilometres in diameter, with rather smaller bodies several kilometres to the south and west and a much bigger 6x8 km intrusion 5 km north of Mont Troquoi. All the intrusions are of syenite with some facies containing quartz. They comprise microcline, albite, aegirine-augite, which is generally associated with arfvedsonite, biotite and accessories. Six rock analyses are given by Papon (1973).