1967 Hay River Area Airborne Magnetometer Survey - Acquisition & Interpretation Report

Abstract

The 1967 Hay River Area Airborne Magnetometer Survey was carried out by Adastra Hunting Geophysics Pty Ltd in 1967 within OP146. The purpose of the survey was to ascertain the thickness of sediments, trends of major structural features such as faults and magnetic intrusions, and the locations (if any) of basin boundaries. The information gained from the survey to be used as a guide in selecting areas of interest for further more detailed, geophysical surveys in the search for oil bearing zones.

Zones based on differing magnetic character have been delineated. Two localised basins have been defined in the extreme east of the area, containing up to 7000 feet of sediments. However their positions relative to outcropping, thick sequences of non magnetic Late Proterozoic Sandstone suggests local development of these sediments preserved in shallow basins in the Older Precambrian basement surface. The A and E zones have a magnetic pattern characteristic of very deep basement. In zone E, this basement could be up to five miles deep. This is not consistent with current concepts if geology in the area, and the magnetic pattern probably relates to a heterogenous acidic pluton. A similar environment could explain the pattern of zone A, a more likely explanation is a fairly thick sequence of generally non-magnetic sediments of unknown age. Micro anomalies indicative of shallow sources further complicated the magnetic pattern of zones A and B. The deeper areas of zones A and E warrant more consideration. If a deep basement is favoured, then some of the micro anomalies should be analysed further to attempt to determine sedimentary structures.