PALEOMAGNETISM OF DEVONIAN SEDIMENTARY-ROCKS AND MAFIC SILLS FROM THE MEGUMA TERRANE, NOVA-SCOTIA

Paleomagnetic data were obtained from the Lower-Middle Devonian Torbrook Formation (7 sites) which consists of fossiliferous shales, siltstone and quartzite and mafic intrusions (10 sites) composed mainly of gabbro sills. Some but not all the sills intrude the Torbrook Formation. Thus, some of these intrusives are of Silurian age while others are Late Devonian. The natural remanent magnetization site-mean directions are scattered but discordant from the present Earth's field for both the sedimentary rocks and the sills. The pole positions are compared with those of the same age from Laurentia, Gondwana and the Avalon Terrane. During the Silurian period, the Meguma and Avalon zones were apparently not part of the same landmass. By Early-Middle Devonian time, both the Meguma Terrane and Avalon Zone had docked unto the North American craton. The dissimilarity in the apparent polar wander paths and paleolatitudes of Africa and the Meguma Terrane does not support a North African provenance for the Meguma Zone. -from Authors