The aeromagnetic survey program of the Geological Survey of Canada: contribution to regional geological mapping and mineral exploration

Abstract

The aeromagnetic survey operations of the Geological Survey of Canada (GSC) began in 1946, utilizing a magnetometer in a bird system towed by a Royal Canadian Air Force Anson. Subsequent early operations were carried out by the GSC-operated Canso and Aero Commander aircraft. In 1961, the GSC in-house survey team formed the nucleus of a contract surveys group set up to monitor a new program established to complete the aeromagnetic mapping of the Canadian Shield in 12 years on a cost-sharing basis with the provinces. Today, surveys are carried out under contract by light twin-engine aircraft such as the Cessna 404 and even, in some cases, single-engine aircraft that utilize compact computer-controlled data acquisition and navigation systems and inboard magnetometer installations. Early systems were capable of resolution of only a few nanoteslas (nT) compared to the current standard of 0.1 nT or less, and flight path positioning with 35 mm film and photomosaics or topographical maps was extremely challenging. Despite these limitations, the careful selection of survey parameters and attention given to quality control have resulted in a world-class aeromagnetic data base that has contributed significantly to regional geological mapping and to mineral and oil exploration in Canada. Concurrently, the GSC carried out research programs into the development of instrumentation and into processing, interpretation, and enhancement techniques. In 1968, the GSC acquired its own platform, a Beechcraft B80 Queenair, which was used to develop high-sensitivity techniques, and an inboard gradiometer system, which was transferred to private industry in 1983. The GSC, in cooperation with the Flight Research Laboratory of the National Research Council of Canada, has also conducted a program of research into magnetometry and navigation combined with aeromagnetic studies of the Arctic since 1962.

New digital data base helps to map North America

“…Canadian Data. Canada has conducted a systematic aeromagnetic mapping program since 1947 [Teskey et al, 1993], often on a costsharing basis between federal and provincial governments. Surveys are contracted out by the GSC and are often jointly funded with industry partners from both the petroleum and mining sectors.…”

“…The leveling and merging of aeromagnetic surveys in Canada to produce a country-wide compilation was started in the late 1970s. A second phase was started in the late 1980s and has continued, resulting in a regional compilation for the majority of the Canadian land mass and offshore area [Teskey et. al, 1993] .As part of the new North American map, the remaining data-which mostly cov ers the Arctic Islands-will be merged with the existing data base to produce the most upto-date coverage of Canada.…”

An assessment of long-wavelength magnetic anomalies over Canada

“…This national program has maintained a standard set of survey parameters of 0.5 mi (805 m) line spacing and 1000 ft (305 m) mean terrain clearance wherever possible (Teskey et al 1993). As part of the production of a 1 : 1000000 scale map series started in 1977, early analog surveys were digitized to form a database of gridded magnetic data at an interval of 812.8 m (Dods et al 1985 (1969,1970,1972,1974,1976).…”

Integration of an Aeromagnetic Measurement System Based on an Unmanned Aerial Vehicle Platform and Its Application in the Exploration of the Ma’anshan Magnetite Deposit

“…It is characterized by a high speed and low exploration cost, and it can cover regions that are difficult to access, such as volcanic areas [2]- [4]. Aeromagnetic survey is used in large-scale regional geological mapping and mineral and oil exploration [5], [6]. In addition, aeromagnetic exploration plays an important role in the mapping of buried igneous rocks and geological structure divisions, as well as in geothermal, and groundwater investigations [7]- [13].…”