Geology and petrology of the anorthosite and associated rocks of the Chertsey map-area.

The area covers the eastern portion of the Morin anorthosite massif north of Montreal. The mapped geological units include a zone of coarse anorthosite of the "Ashton facies", a quite broad zone of sheared anorthosite of the "Chertsey facies", concordant bodies of sheared quartz mangerite, and an elongated boss of unsheared alaskite; rocks of the Grenville series bound the massif on its eastern side and form several 'inclusions' within the anorthosite and the mangerite. [...