Douglas Merrett

B. Sc. Honours Thesis

The Petrology and Geochemistry of the Port Mouton Migmatites

(PDF - 9.9 Mb)

This study is centered on the migmatites found along certain portions of the contact between the Port Mouton pluton of Shelburne and Queens counties, Nova Scotia, and the local host lithology. The field relations, petrology and chemistry of samples taken were studied to determine the genetic processes and the geochemical nature of the migmatites.

The Goldenville Formation (host lithology) consists of two units, the competent quartz-rich psammite showing little melting or distortion, and the aluminous, semi-pelitic schist, the metamorphosed equivalent of semipelitic interbeds in the psammite. This has been intruded by the Port Mouton pluton and is cut in the thesis locality by pegmatitic, aplitic, tonalitic semipelitic interbeds were more ductile during emplacement and tended to be intruded preferentially by granitic phases. The semipelites are almost always strongly folded and contorted, appearing to mix with the intruding dykes in places.

Chemical and petrographic evidence suggests that most leucosomes have hybrid compositions due to melt mixing between the injections and partial melts in the host. There is an indication of at least local equilibration between the granite and psammite lithologies.

Keywords:
Pages: 146
Supervisor: D. Barrie Clarke