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Survey Background

FINDLAY RIVER GEOPHYSICAL SURVEY
GSC Open File 3495
Aeromagnetic Residual Total Field Map, British Columbia
(Parts of NTS 94E/NE)
Dumont R., Coyle M., Stone P.

The aeromagnetic survey was carried out from July 21st to September 9, 1997 by Sander Geophysics Ltd, using two Cessna208B Grand Caravan  aircraft and a BN2B-21 Islander aircraft. A 0.005 nT sensitivity split-beam cesium vapour magnetometer was mounted in the tail boom of the survey aircraft.

The nominal traverse line spacing was 800 meters with control lines at 5 kilometres spacing at a nominal terrain clearance of 305 meters. A pre-planned flight surface was calculated for this survey to minimize the control line and traverse line altitude differences. Flight path was recovered using a post flight differential Global Positioning System, combined with a vertically mounted video camera.

After editing the survey data the intersections of the control and traverse lines were established and differences in the magnetic values were computer analyzed and manually checked to obtain the level network. The levelled total field values were then interpolated to a 200 meter grid. The International Geomagnetic Reference Field has been removed for the year 1997 75 at an altitude of 2060 meters.

Shading from the calculated magnetic vertical gradient is superimposed on the colour residual magnetic intensity to enhance subtle features present in the dataset.

Copies of this map may be obtained from the Geophysical Data Center, Geological Survey of Canada, 615 Booth Street Ottawa, Ontario, K1A 0E9. It is also available online at the MIRAGE and at the Geoscience Data Repository.  The geophysical data used to compile this map are available in digital form from the Geophysical Data Centre, Geological Survey of Canada, 1 Observatory Crescent, Ottawa, Ontario. K1A OY3.

Analogue and digital products include data for magnetic parameters in two projections: