IV. Regional studies. Hudson Geotraverse: geology of the Mid-Atlantic Ridge at 45° N/ Petrology of submarine volcanics from the NE Pacific

Abstract

Palaeomagnetic data from two volcanoes of the Aden Volcanics shows 7 degrees anticlockwise rotation of this part of Arabia relative to Africa during the last 5 Ma. On theoretical grounds this amount of deviation should not be detectable from other sources of scatter, in particular that caused by averaging the secular variation. It is suggested that this deviation is probably real as it is shown in both volcanoes, but further detailed work is necessary to distinguish between anomalous secular variation and the suggested tectonic interpretation. Studies of older rocks in both Arabia and Africa show that the Mesozoic anticlockwise rotation of Africa relative to the axis of rotation had ceased by the late Cenozoic and this movement, together with the evolution of Turkey and the Zagros Mountains, must be considered within the problem of the tectonic evolution of the Red Sea-Gulf of Aden area.