scholarly journals Composite lithology-magnetic anomaly image, Fort Fraser, British Columbia

2000 ◽  
Author(s):  
C Lowe ◽  
R Kung ◽  
L C Struik
Keyword(s):  
British Columbia ◽  
Magnetic Anomaly

scholarly journals Total field magnetic anomaly, offshore British Columbia

1982 ◽  
Author(s):  
R G Currie ◽  
D A Seemann ◽  
R P Riddihough
Keyword(s):  
British Columbia ◽  
Magnetic Anomaly ◽  
Total Field

Magnetic anomalies and rock magnetizations in the southern Coast Mountains, British Columbia: possible relation to subduction

1977 ◽  
Vol 14 (8) ◽  
pp. 1753-1770 ◽  
Author(s):  
R. L. Coles ◽  
R. G. Currie
Keyword(s):  
Magnetic Material ◽  
British Columbia ◽  
Magnetic Anomaly ◽  
Western Coast ◽  
Coast Mountains ◽  
Deep Crust ◽  
High Oxygen Pressure ◽  
Plutonic Complex ◽  
Coast Plutonic Complex ◽  
Trend Variation

A qualitative correlation is observed between the northwesterly trending Coast Mountains Magnetic Anomaly, British Columbia, and a systematic, cross-trend variation of measured magnetizations within the more mafic rocks from the Coast Plutonic Complex between 50° and 51° N. This variation partly determines the form of the anomaly. A similar variation of magnetizations in more acidic rocks is not found. Quantitative modelling, however, indicates the presence of deeper, intense magnetizations below the high anomaly in the west. A magnetic crust as much as 40 km thick is consistent with geothermal studies in this region. The deep crust of Vancouver Island is less magnetic than that under the western Coast Plutonic Complex. The concentration of magnetic material may be a consequence of a subduction process, whereby water released by dehydration of the downgoing slab promotes partial melting, with subsequent uprising of heat and melt within a hydrous environment. The water tends to maintain a relatively high oxygen pressure, at least locally, and magnetite forms in the crystallization sequence. As subduction proceeds, this region cools and the magnetic material may then produce a high magnetic anomaly.

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