AEROMAGNETIC STUDY OF THE CHURCHILL–SUPERIOR BOUNDARY IN NORTHERN MANITOBA
ABSTRACT A regional aeromagnetic study of northern Manitoba suggests adjustments in the position of the Churchill–Superior boundary. This proposed boundary is correlated to a narrow, continuous magnetic low that changes direction at its northern end, from a northeast trend to an east–west trend that approximately parallels the 56° N. latitude line.The date pattern of age determinations chiefly supports the position of the proposed boundary. Comparison of aeromagnetic patterns to the geology establishes their close correlation. Aeromagnetic anomalies appear to be chiefly produced by near-surface material and can be correlated with the surface geology. A comparison of the gravity patterns to the aeromagnetic and geologic patterns establishes the apparent independence of the gravity patterns to the other two. The gravity anomalies appear to be produced by larger scale density contrasts which are not correlative with near-surface material. A deeper, crustal source of the gravity anomalies fits the evidence better.
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ABSTRACT: An integrated aeromagnetic-geologic interpretation of the Moak Lake – Setting Lake structure, a distinctive magnetic feature which contains the Manitoba nickel belt, is presented. This structure is separated, on the basis of aeromagnetic and geologic data, into eastern and western areas. A main fault zone, which is mapped in part and is also an aeromagnetic lineament, separates the two areas. It is deduced that the western area of the Moak Lake – Setting Lake structure was involved in the Hudsonian orogeny only. The eastern area is interpreted to have been initially involved in the Kenoran (?) orogeny, which produced the characteristic charnockite and pyroxene granulite rocks, and was then reinvolved in the dynamic effects of the Hudsonian orogeny. A chronologic sequence of the major events in the area is presented.Canadian Journal of Earth Sciences 02/2011; 6(3):373-381. · 1.37 Impact Factor