The Pointe-des-Monts diabase swarm crops out along 3 km of shoreline at Pointe des Monts, Quebec, Canada. Most of the dykes are aphyric diabase 10 to 100 cm thick with chilled margins to migmatites and intrusive rocks of the Grenville province. There are also a few dykes with plagioclase phenocrysts and also two composite diabase/aplite dykes. Although the dykes appear in many outcrops to be post-Grenville they are deformed in places where they host minor garnet crystals. The age of the dykes is unknown but they must be very late Grenville, maybe around 1000 Ma.
BSc thesis: Dominique
Meilleur. CARACTERISATION
ET
CHRONOLOGIE DE L'INTRUSION DE POINTE-DES-MONTS ET DES DYKES DE DIABASE,
POINTE-DES-MONTS, QUEBEC. UQAC, 2000