AbstractsEarth & Environmental Science

The sedimentary, volcanic and intrusive rocks of an area in the northern part of the Canadian Shield are described. Particular reference is made to the relative ages of these formations* their structures, and to major faults. The field evidence suggests that a red feldsparporphyry intrusive is younger than the granite which intrudes the volcanic porphyries. This, and to some extent the stratigraphic sequence proposed differ from previous findings. The distribution and attitudes of the sedimentary and volcanic formations indicate a flexure in a regional northv/esterly-trending open fold- Two sets of right-hand faults strike northerly and northeasterly respectively. The latter are marked by large displacements and in places by giant quartz veins. The horizontal movement along one such northeasterly-trending fault is determined as three to four miles. The age relations and causes of faulting are discussed.