A Devonian palaeomagnetic pole for Armorica

Abstract

The palaeomagnetic study of Siluro‐Devonian redbeds of the San Pedro formation, at Cabrillanes, Asturias, Spain, reveals a high temperature and pre‐tectonic magnetization determined by intersection of great circles as well as conventional averaging (Fisher). This magnetization is carried by the haematitic pigment and is therefore of chemical and post‐ depositional origin. The formation mean direction (D= 113°, I=+34°, α95= 10°) is interpreted as representing a record of a Devonian palaeofield. The corresponding pole after correction for the opening of the Bay of Biscay and the tectonic closure of the Ibero‐Armorican arc is in good agreement with contemporaneous European poles, confirming that the Armorica plate had already joined the Laurentia‐Baltica assembly at that time. Copyright © 1984, Wiley Blackwell. All rights reserved