Silva, PedroHenry, B.Marques, Fernando O.Madureira, P.Miranda, Jorge Miguel2012-03-212012-03-212006-11-01SILVA, Pedro F.; [et al] – Paleomagnetic study of the Great Foum Zguid dyke (southern Morocco): A positive contact test related to metasomatic processes.Geophysical Research Letters. ISSN 0094-8276. Vol. 33, N.º 21 (2006), pp. 1-6.0094-8276http://hdl.handle.net/10400.21/1325When a paleomagnetic pole is sought for in an igneous body, the host rocks should be subjected to a contact test to assure that the determined paleopole has the age of the intrusion. If the contact test is positive, it precludes the possibility that the measured magnetization is a later effect. Therefore, we investigated the variations of the remanent magnetization along cross-sections of rocks hosting the Foum Zguid dyke (southern Morocco) and the dyke itself. A positive contact test was obtained, but it is mainly related with Chemical/Crystalline Remanent Magnetization due to metasomatic processes in the host-rocks during magma intrusion and cooling, and not only with Thermo-Remanent Magnetization as ordinarily assumed in standard studies. Paleomagnetic data obtained within the dyke then reflect the Earth magnetic field during emplacement of this well-dated (196.9 +/- 1.8 Ma) intrusion.engMagnetic-PropertiesAtlanticPaleomagneticFoum Zguid dyke (southern Morocco)Chemical/Crystalline Remanent MagnetizationMetasomatic processesThermo-Remanent Magnetizationjournal article10.1029/2006GL027498