Origin of Foliation in the Barrington Passage Pluton
Gallant, Geoffrey K.
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New studies provide insight into the processes producing the penetrative foliation observed in the Barrington Passage Pluton (BPP). Preferred alignment of primary minerals, imbrication of feldspars, preferred alignment of enclaves, schlieren layering, and orientation parallel to the contact suggest a magmatic flow origin for most of the BPP. However, features such as recrystallized quartz and biotite, fractured and rotated feldspars, anastomosing foliations, and `S-C' foliations characterize a gneissic texture present along the western margin of the BPP. Local deformation in the area is the result of a shear zone. A younger norite intrusion occurs within the BPP and has locally deformed the tonalite host. There is resetting of the foliation around the norite body. Deformation including extensive plagioclase alteration, fractured and broken feldspars, and recrystallized and reoriented biotite characterize the BPP rocks near the norite body. Forceful intrusion of the norite produced effects on the BPP similar to those produced upon wall rocks by ballooning pluton. Recrystallized quartz aggregates occur throughout the study area, and align parallel to the foliation. Quartz is the only deformed mineral among the magmatically produced foliation samples. This suggests that solid-state deformation is very slight in the BPP. Kwywords: folliations, submagmatic, tectonic, solid-state, shear zone, deformation, norite, tonalite, ballooning plutons, syntectonic Pages: 129 Supervisor: D. Barrie Clarke