Comparisons of magnetic anomalies of lithospheric origin measured by satellite and airborne magnetometers over western Canada

Abstract

Crustal magnetic anomaly data from the Orbiting Geophysical Observatories 2, 4, and 6 (Pogo) satellites are compared with upward-continued aeromagnetic data between 50–85°N latitude and 220–260°E longitude. Agreement is good, both in anomaly location and in amplitude, giving confidence that it is possible to proceed with the derivation and interpretation of satellite anomaly maps in all parts of the globe. The data contain a magnetic high over the Alpha ridge suggesting continental composition and a magnetic low over the southern Canada basin and northern Canadian Arctic Islands (Sverdrup basin). The low in the Sverdrup basin corresponds to a region of high heat flow, suggesting a shallow Curie isotherm. A ridge of high field, with two distinct peaks in amplitude, is found over the northern portion of the platform deposits and a relative high is located in the central portion of the Churchill Province. No features are present to indicate a magnetic boundary between Slave and Bear Provinces, but a trend change is evident between Slave and Churchill Provinces. South of 60° latitude a broad magnetic low is located over very thick (40–50 km) crust, interpreted to be a region of low magnetization.