Similarity of new palaeomagnetic data from the Santa Rosa Mountains with those from Steens Mountain gives wide regional evidence for a two‐stage process of geomagnetic field reversal

Abstract

New palaeomagnetic data of much improved resolution are presented for the geomagnetic field reversal recorded by lavas of the Santa Rosa Mountains in Nevada, USA; five of six intermediate field directions have α95 values of less than 5.5°. The variation in the direction of the palaeomagnetic field recorded by the Santa Rosa lavas is of striking similarity to that recorded by a sequence of lavas of similar age at Steens Mountain, Oregon, 200 km away. The data from the Santa Rosa lavas represent an important field test to substantiate the detailed recording of a two‐stage geomagnetic field reversal in the middle Miocene at Steens Mountain (Watkins 1969; Mankinen et al. 1985.) Copyright © 1990, Wiley Blackwell. All rights reserved