HR: 14:30h
AN: GP23A-03    [Abstracts]
TI: Paleomagnetism of the Late Proterozoic Sierras Bayas Group and the Ediacaran-Cambrian Apparent Polar Wander Path of the Rio de la Plata Craton
AU: * Rapalini, A E
EM: rapalini@gl.fcen.uba.ar
AF: INGEODAV, Dept. Cs. Geol., FCEN, Univ. Buenos Aires, Pab.2, Ciudad Univ., Buenos Aires, C1428EHA, Argentina
AU: Trindade, R I
EM: rtrindad@iag.usp.br
AF: IAG, Universidade de Sao Paulo, C. Univ., Sao Paulo, Brazil
AU: Poiré, D G
EM: poire@cig.museo.unlp.edu.ar
AF: CIG-CONICET, Univ. Nacional de La Plata, Calle 1, La Plata, Argentina
AU: Vieira, L
EM: lvieira@iag.usp.br
AF: IAG, Universidade de Sao Paulo, C. Univ., Sao Paulo, Brazil
AB: The apparent polar wander path (APWP) of the Rio de la Plata craton (RP) for the Late Proterozoic and Early Paleozoic is of significance to reconstruct the tectonic processes that led to the amalgamation of Gondwana. In order to define the Ediacaran-Cambrian APWP for RP, a systematic paleomagnetic study was carried out in the Sierras Bayas Group exposed in the province of Buenos Aires, Argentina. 328 samples from 44 sites were collected in the Cryogenian to Ediacaran Villa Mónica Fm., the Ediacaran Cerro Largo, Loma Negra and Las Aguilas Fms. and the Cambrian (?) Cerro Negro Fm. Sampling included mainly limestone and dolomite, red claystone and marls. Although most sites presented secondary magnetizations of likely recent and Permian (?) age, a few sites from the Cerro Largo and uppermost Villa Mónica Fms. carry a pre-tectonic magnetization that yielded a preliminary paleomagnetic pole at 34.6°S, 211.3° (6.4°/10-9°; n: 18 samples), while a pre-tectonic remanence from the Cerro Negro Fm. yielded a paleomagnetic pole at 10.9°N, 323.5°E (9.7°/13.3°, n:17 samples). These two preliminary paleomagnetic poles for the Sierras Bayas Group together with previously published ones permit to define with confidence the APWP of RP from ca. 600 to ca. 500 Ma.
DE: 1527 Paleomagnetism applied to geologic processes
DE: 1599 General or miscellaneous
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly