Petrology, mineral chemistry and geochronology of the Eagle, F.D. no. 5, and Tappy pegmatites: Cat Lake-Winnipeg River Pegmatite Field, southeastern Manitoba, Canada

Abstract

The Eagle, F.D. no. 5, and Tappy are spodumene-bearing, Li-Cs-Ta (LCT) class, rare-element pegmatites. The Eagle and F.D. no. 5 dykes are spatially related: both located in the Cat Lake-Maskwa Lake pegmatite district in the northern part of the Bird River Domain in southeastern Manitoba. However, petrologically and chemically they do not appear to be part of the same body. The Tappy pegmatite is hosted within the Winnipeg River pegmatite district to the south. All three dykes are emplaced near vertically and have good exposure with accessible locations near roads making them all prospective targets for critical mineral development. U-Pb geochronology on tantalite and monazite gives near contemporaneous ages for the Eagle, F.D. no. 5, and Tappy dykes at ~2650 Ma, placing them all within the D3 deformation event in the Bird River, coeval with widespread granitic magmatism and other pegmatites in the region.