New paleomagnetic data from the late Ediacaran sedimentary cover of the Tandilia System: paleogeographic implications for the Rio de la Plata craton

Abstract

Paleomagnetic studies were performed on samples from two bore cores from the Avellaneda Formation at the Alicia quarry, located in the Olavarría area of the Tandilia System, in the Río de la Plata craton. High temperature demagnetization yielded a mean characteristic remanence direction of Dec: 14.6°, Inc: 67.4°, k: 31.3, α95: 8.3° N:11 after bedding correction. This direction in combination with those obtained by Franceschinis et al. (2022) for the same unit in the La Cabañita quarry, permitted the calculation of a refined paleomagnetic pole for the ca. 570 Ma Avellaneda Formation at: 0.9° S, 312.5° E, A95: 5.2°. The apparent polar wander path (APWP) for the Rio de la Plata Craton during the Late Ediacaran was analyzed and a new alternative path is presented considering an opposite polarity for poles older than ca. 580 Ma. This path resembles the recently proposed APWP of West Africa craton, whose large oscillations were attributed to two events of inertial interchange true polar wander (IITPW).