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Kean & Swingen 1981
Kean, W.F. and Swingen, R.A. (1981). Paleomagnetism of a keweenawan age intrusive near Clam bake, Wisconsin. Geophysical Research Letters 8: doi: 10.1029/GL008i006p00579. issn: 0094-8276.

Two long cores from a magnetite-rich gabbroic intrusion near Clam Lake, Wisconsin were studied to obtain paleopole positions to aid in determining the time of intrusion and learn more about the tectonics of the area. This intrusion was suspected to be late Precambrian in age. A. F. demagnetization above 150 oe. produced reliable remanent directions. The cores were not azimuthally orientated, therefore small circle plots were made for each sample using 12 different horizontal orientations. The best pole position was considered to be where the small circle paths crossed the Precambrian polar wander curve. This gave a normal pole at N 30¿ E 176¿ which is middle Keweenawan in age. The average inclination and declination for 14 of the 18 core sections was 35¿ and 288¿ respectively, which is consistent with aeromagnetic maps of the area. the 35¿ inclination is consistent with most middle Keweenawan rocks of the area, after they have been corrected for a 10¿--30¿ tilt. This suggests that the Clam Lake area was not tilted after intrusion. Basalt dikes in the gabbro gave consistently lower inclinations which suggest a late Keweenawan time for their formation.

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Geophysical Research Letters
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American Geophysical Union
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