XLII. Rock magnetism in India

Abstract

Measurements have been made of the magnetic polarization of 450 specimens of basaltic lavas of the Deccan Trap taken from two sites about 500 miles apart. With the exception of some nearly randomly magnetized specimens, the main direction of magnetization is N. 155° E. and the dip is 53° downwards. The most plausible interpretation of this result is (a) that India has drifted north from a position about 34° south of the equator when the rocks were formed some 70 million years ago and has rotated anti-clockwise through 25°, and (b) that either the earth's field was reversed when the rocks were formed or that the rocks became magnetized in the opposite direction to the field by some physico-chemical mechanism. The pole position corresponding to these results does not agree with that found by other workers for British and American rocks of the same period. This suggests that a movement of India, relative to North America and Europe, has taken place at some time during the past 70 million years.