IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PALEOMAGNETIC STUDIES ON THE EDICACARAN-CAMBRIAN PUNCOVISCANA AND LATE CAMBRIAN CAMPANARIO FORMATIONS: NEW PALEOGEOGRAPHIC CONSTRAINTS FOR PAMPIA TERRANE
Autor/es:
FRANCESCHINIS, PABLO; RAPALINI, AUGUSTO E.; ESCAYOLA, MÓNICA; LUPPO, TOMÁS
Lugar:
Sao Paulo
Reunión:
Congreso; LatinMag 2015; 2015
Institución organizadora:
Asoc. Latinoamericana de Paleomagnetismo y Geomagnetismo
Resumen:
Amagnetofabric and paleomagnetic study was carried out in the latest Ediacaran ?Early Cambrian Puncoviscana and the early Late CambrianCampanario Formations,exposed in Santa Victoria Oeste, in northwestern Argentina. The anisotropy of magneticsusceptibility (AMS) allowed to recognize a pre-tectonic fabric in bothformations indicating that it is previous to the Andean cycle. Reliablemagnetic components were isolated in only two out of ten sites on a tuff, datedas 537 Ma, and an andesitic sill interbedded in the turbiditic sequence of the PuncoviscanaFormation. The virtual geomagnetic poles (VGPs) for these sites are close tothe apparent polar wander curve of Gondwana for the Late Neoproterozoic -Cambrian. The Campanario Formation was carrrier of a pre-tectonic magneticremanence slightly affected by compaction that was corrected with data obtainedfrom directional IRM. Its paleomagnetic pole (18.3°S, 359.9°W, dp:2.9°,dm:5.2°) is close to but does not coincide with those obtained previously in thisformation at other locations and that have been used to propose a Cambrianaccretion of Pampia to Gondwana by transcurrent displacements. However the polepresented here is closer to the reference apparent polar wander path ofGondwana suggesting two possible interpretations; the presence of Andeantectonic rotations between different study locations or a record of rapid dextraldisplacement of Pampia along the Gondwana margin in Cambrian times.