Jurassic Apparent Polar Wander of Pangea: Evidence of True Polar Wander?

IGLESIA, P.; PREZZI, CLAUDIA BEATRIZ

Isla de Margarita

Congreso; Primera Reunión Bienal de la Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo; 2009

During the Late Carboniferous until the Middle Jurassic continents were assembled in a quasi-rigid supercontinent called Pangea. Most palaeomagnetic poles from South America during this time cluster close to the geographical pole and therefore, it has always been interpreted that the continent remained more or less stationary in similar present-day latitudes (e.g. Valencio et al. 1983, Oviedo and Vilas 1984, Rapalini et al. 1993, Beck 1999). However, in a more recent study other authors question the validity of such model at least during the Early Jurassic, particularly in the case of South America (Iglesia Llanos et al. 2006, 2008). Furthermore, after a thorough compilation of palaeomagnetic data from international databases the apparent polar wander (APW) paths of the four major Pangean continents depict the same shape, length and chronology of tracks. Cusps like this are commonly related to a major plate reorganisations, although no significant tectonic events are recorded during the Early Jurassic in Pangea. This correspondence in the curves aims at that either Pangea moved at relatively high rates or that true polar (TPW) prevailed particularly during the Early Jurassic, meaning that the entire Earth moved with respect to the spin (=palaeomagnetic) axis. On this basis, we correlate the South American APW path with those from Eurasia, Africa and North America to investigate the probable origin of the Early Jurassic cusp.