AIRBORNE GEOPHYSICAL RECONNAISSANCE IN THE CANADIAN ARCTIC ARCHIPELAGO

Abstract

Profiles of total magnetic intensity and gamma radioactivity were obtained along a series of widely‐spaced flight lines across the main tectonic regions of the Canadian Arctic Archipelago. The interpretation of these data and the calculated depths‐to‐basement substantiate the recognized regional structures, confirm general geological continuity between the islands, and provide some additional structural detail. Results of particular interest are the maximum depths‐to‐basement in the sedimentary basins (10,000 ft or greater), the interpretation of the structure of the Precambrian arches, the extent of nonbasement igneous activity, the apparent absence of disturbed ferromagnetic rocks on the Polar Continental Shelf except near the edge where a few deep basement‐type anomalies were observed, and the occurrence of anomalous radioactivity in certain sedimentary rocks on Bathurst Island. Remarkable magnetic anomalies, which in profile show a central minimum with marginal maxima, are characteristic of known gypsum domes in the Sverdrup Basin. It is concluded that reconnaissance geophysical surveys of comparable geological regions can provide much information concerning the structure and lithology of the area. In particular, this survey reveals geophysical contrasts of significance in the planning of future investigations in the archipelago and points out a number of interesting anomalies which require further study.