Structural and magnetic fabric study of the late Archean Sparrow and Prosperous plutons, Prosperous suite, Slave Province, Canada.

• Main Author: Ham, Natalie M.
• Format: Thesis
• Language: unknown
• Published: Université d'Ottawa / University of Ottawa 2001
• Subjects: Geology.; Canada; Yellowknife
• Online Access: https://dx.doi.org/10.20381/ruor-7576; http://www.ruor.uottawa.ca/handle/10393/8959

The late Archean (∼2595 Ma) Sparrow and Prosperous granite plutons near Yellowknife, NWT, intrude cordierite and andalusite bearing metagreywacke typical of the Slave Province. The objective of this thesis is to determine the structure of the plutons, mode of emplacement and timing in relation to regional deformation. Field and microstructural studies of the plutonic and host rocks are complemented by an analysis of the anisotropy of magnetic susceptibility (AMS) of the granites. Minor recrystallization of quartz within the plutons, with most grains showing subgrain development, suggests that the fabrics in the granites formed before the granites had completely cooled, probably during emplacement. Paramagnetic Fe-phyllosilicates (biotite and chlorite) and very fine-grained magnetite contribute to the magnetic susceptibility and its anisotropy. Magmatic mica-rich and mica-poor layers lie parallel to a shallow-dipping basal contact of the Prosperous pluton. The plutons are inferred to have been emplaced during a second phase of regional deformation (D2). It is proposed that the Sparrow and Prosperous plutons are laccoliths that were emplaced horizontally during D2 deformation, and subsequently were deformed as they crystallized during later stages of D2. (Abstract shortened by UMI.)