SECT. 1] 



THE MAGNETIC FIELD OVER THE OCEANS 



201 



and the sharp flexures of the pattern immediately north of the fault, suggest a 

 right -lateral movement of the continent relative to the oceanic crust. This is in 

 the same sense as the movement along the San Andreas Fault, and along the 

 tentative NW-SE fault indicated in Fig. 12a. 



300 



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OCEAN 

 SEDIMENTS 



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MAIN CRUSTAL LAYER 



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OCEAN 

 SEDIMENTS 



-BASEMENT TOPOGRAPHY 



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 MAIN CRUSTAL lAYER 



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 SEDIMENTS 



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MAIN CRUSTAL LAYER 



12 L MANTLE 



Fig. 16. Three possible interpretations of the magnetic profile along line A-A of Fig. 12a, 

 in terms of two-dimensional sections adjusted to fit the anomaly exactly. 



Two further facts must be taken into account in any hypothesis about the 

 origin of the crustal displacements. The first is that they are not matched on 

 the adjacent continent. Where the Mendocino Fault intersects the continental 

 slope there is a right-lateral offset of about 100 km, but this is in the opposite 

 direction to the displacement of the magnetic pattern. There is no offset of the 

 continental slope along the line of the Murray Fault, but small east-west 



