Geology of the St. Agnes Lake District, Alberta

The geology of a 74 square-mile area in the Precambrian Shield of northeastern Alberta is shown on a colored map of a scale of 2 inches to 1 mile. The western part of the map-area is underlain by a granite gneiss complex containing bands and patches of high-grade metasedimentary rocks; the eastern part is underlain by a group of porphyroblastic biotite granites with massive biotite and leucocratic granites. Ten rock types are described with regard to hand specimen characteristics, field occurrence, contact relations, and chemical and modal analyses. Schistosity and foliation are well developed in most of the rock-units, and small-scale folds and shear zones are common. A system of north northwest trending faults cut the prevailing northerly strike of the major rock units.