Palaeomagnetic Stratigraphy of Tertiary Lavas from Northern Ireland

Abstract

Three lava profiles, sampled at 1.3 km and 2.3 km spacings, overlap stratigraphically as proven by two geological marker horizons. Groups of several successive lavas often have remarkably coherent directions of magnetization. Further, on three occasions, a group of lavas in one profile correlates palaeomagnetically with a group in another profile, and these correlations agree very well with the geological marker horizons. A lava‐mean α95 of 3.1° makes possible palaeomagnetic stratigraphy based on secular variation, apparently within one polarity epoch (reversed). Since many lavas seem to have recorded virtually the same magnetic field, 54 distinct lavas contribute only 25 distinct spot values of the ancient field, from which we deduce a mean pole position at 69.6° N and 162.9° E, with P= 5° and M= 7°. Copyright © 1970, Wiley Blackwell. All rights reserved