Paleomagnetic directions from two sites at Mono Lake, California, 24000 years ago traced-out a well-defined counter-clockwise loop 25° in diameter. Major features of the loop can be explained by an inward directed radial dipole located at 0.5 Earth's radius, drifting eastward along a path 15° south of Mono Lake. Its longitudinal velocity was 0.10-0.19°/yr and its strength was 0.12-0.21 relative to the Earth's main dipole moment. The life-span of this perturbing source probably was similar to the period of the magnetic loop, about 850 years.
No takes yet. Share an insight, caveat, or question.
Charles R. Denham (1974) studied this question.