The Palaeomagnetism of Late Cenozoic Volcanic Rocks from Kenya and Tanzania

Abstract

Palaeomagnetic results from 246 sites in the East African Cenozoic volcanics are reported. Palaeomagnetic pole positions are obtained for different age ranges as follows: 0–1.8 My, 104° E, 89° N, A95= 3° (54 sites); 1.8–7.0 My, 148° E, 87° N, A95= 2° (102 sites); around 12 My, 187° E, 87° N, A95= 6° (22 sites); around 17 My, 163° E, 85° N, A95= 2° (62 sites). Apart from the youngest these poles show a far-sided and right-handed tendency which is ascribed to a late Tertiary offset dipole field rather than to polar wander. For at least the past 7 My and possibly for the past 13 My, secular variation in East Africa has been large and in accord with model predictions for near equatorial sites. This contrasts with low secular variation observed in Iavas younger than 5 My from the Hawaiian Islands.