Geology of the Colin Lake District, Alberta

The geology of a 75 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 predominant feature of this map area is the Colin Lake synclinorium whose folded axis plunges east, and trends northeast, east and southeast in passing from west to east. The 'basement' granite gneiss complex occupies a small area to the northwest of the synclinorium, where-as the principle rock types - porphyoblastic biotite granites - lie in the synclinorium. The typical northerly regional foliation trends are reoriented by the synclinorium to the extent that easterly trends prevail in the southern half of the map area. Fourteen rock types are differentiated in terms of their field characteristics, and are described in regard to field occurrence, and chemical and modal analyses. Metasedimentary rocks are present in minor amounts only. Many local faults are noted and a few large-scale faults are indicated.