C.E. Jahren
1965
<p><span>Remanent </span>magnetization<span> measurements on 200 oriented samples from the </span>Keweenawan<span> gabbro, diabase, and associated </span>rocks<span> in the </span>Duluth<span> area show a clustering of directions west-northwest and downward. Gabbro samples magnetized in this direction usually have Q, the ratio of remanent to induced </span>magnetization<span>, up to five, whereas other gabbro samples have larger Q. Diabase shows no such generalization. Remanent </span>magnetization<span> is important in all </span>rocks<span> studied. Q ranges from 0.3 to 75, but is less than 1.0 in only 15 samples. Volume magnetic susceptibility averages range from 0.3 × 10</span><sup>-3</sup><span> to 6.0 × 10</span><sup>-3</sup><span>. There is no apparent correlation between magnetic susceptibility and the direction of remanent </span>magnetization<span>. Average directions of remanent </span>magnetization<span> indicate a </span>Keweenawan<span> geomagnetic north pole at latitude 30° to 34° N, longitude 175° to 180° W. </span></p>
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10.1190/1.1439660
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Society of Exploration Geophysicists
Magnetization of Keweenawan rocks near Duluth, Minnesota
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