Large scale magnetic anomalies over western Canada and the Arctic: a discussion

A contoured map of vertical magnetic field residuals (relative to the IGRF) over western Canada and adjacent Arctic regions has been produced by amalgamating new data with those from previous surveys. The measurements were made at altitudes between 3.5 and 5.5 km above sea level. The map shows the f...

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Bibliographic Details
Published in:Canadian Journal of Earth Sciences
Main Authors: Coles, R. L., Haines, G. V., Hannaford, W.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1976
Subjects:
Online Access:http://dx.doi.org/10.1139/e76-082
http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-082
Description
Summary:A contoured map of vertical magnetic field residuals (relative to the IGRF) over western Canada and adjacent Arctic regions has been produced by amalgamating new data with those from previous surveys. The measurements were made at altitudes between 3.5 and 5.5 km above sea level. The map shows the form of the magnetic field within the waveband 30 to 5000 km. A magnetic feature of several thousand kilometres wavelength dominates the map, and is probably due in major part to sources in the earth's core. Superimposed on this are several groups of anomalies which contain wavelengths of the order of a thousand kilometres. The patterns of the short wavelength anomalies provide a broad view of major structures and indicate several regimes of distinctive evolutionary development. Enhancement of viscous magnetization at elevated temperatures may account for the concentration of intense anomalies observed near the western edge of the craton.