HR: 0830h
AN: GP41A-01    [Abstracts]
TI: Paleomagnetism of the Independencia Group, Eastern Paraguay: A New Late Permian Pole for Stable South America
AU: * Rapalini, A E
EM: rapalini@gl.fcen.uba.ar
AF: INGEODAV, Depto.Cs.Geol., Univ. Buenos Aires, Pabell¢n 2, C. Universitaria, Buenos Aires, 1428 Argentina
AU: Fazzito, S
EM: sabrinafazzito@yahoo.com.ar
AF: INGEODAV, Depto.Cs.Geol., Univ. Buenos Aires, Pabell¢n 2, C. Universitaria, Buenos Aires, 1428 Argentina
AU: Orue, D
AF: Fac. Cs. Exactas y Naturales, Universidad Nacional de Asunci¢n, Campus Universitario, S. Lorenzo, Asunci¢n, Paraguay
AB: The late Permian segment of the South American apparent polar wander path (APWP) is poorly defined due to scarce and unreliable paleomagnetic poles, justifying the need for further paleomagnetic efforts on suitable rocks of such age from stable areas of South America. A study was carried out on the Late Permian Independencia Group, which is discontinuously exposed along Eastern Paraguay and consists of several hundred meters of flat lying continental pink to reddish sandstones and siltstones, deposited on the western margin of the Parana basin. Thirteen sites (83 samples) were collected on the top unit of the Group (the latest Permian Tacuary Fm) from outcrops distributed over 1000 square kms. Detailed AF and thermal demagnetization permitted the isolation of within-site consistent characteristic remanence in eleven sites, being generally hematite the main carrier of the remanence. Excluding one outlier, a paleomagnetic pole was computed by averaging 10 virtual geomagnetic poles of mixed polarities (6 reversed, 4 normal), yielding a position at: 80.7 S, 7.0 E, A95: 6.6. The new pole may be considered as key for a better definition of the South American APWP by filling a gap between recently obtained and reliable Early Permian poles and an older and less reliable Early-Middle Triassic group of poles.
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1525 Paleomagnetism applied to tectonics (regional, global)
DE: 1527 Paleomagnetism applied to geologic processes
DE: 8157 Plate motions--past (3040)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly