Figure F18. Spherical projections illustrating the effects of rotation of a remanent magnetic vector initially striking 360° with an inclination of 28° around axes striking 360°040° and plunging 10° to +10°. The initial position of the vector is indicated with a black cross. The rotation axis is shown as a square. Closed symbols = projection points in the lower hemisphere, open symbols = projection points in the upper hemisphere. Small circles = projection points of the rotating magnetic vector plotted at 20° rotation intervals, large circles = magnetic inclinations of 28° (blue = expected at this latitude), 15° (black = average observed in gabbroic rocks), 28°, and 36° (dashed = average observed in talc-altered peridotites). Effects on the inclination are relatively large and are sufficient to account for the observed inclinations in gabbronorite and peridotite in Hole 1268A. Also, in some cases, the effects on the azimuth of the remanent magnetization vector are large. For example, in the most extreme case illustrated, the azimuth changes by almost 90° of counterclockwise rotation around an axis striking 040° and plunging 10° to the south (lower left). CW = clockwise, CCW = counterclockwise.
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