HR: 1340h
AN: U33A-0022    [Abstracts]
TI: The Tarim APWP Paradox
AU: * Gilder, S
EM: gilder@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, Paris cedex 05, IdF 75252 France
AU: Cogne, J
EM: cogne@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, Paris cedex 05, IdF 75252 France
AU: Courtillot, V
EM: courtil@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, Paris cedex 05, IdF 75252 France
AU: Chen, Y
EM: Yan.chen@univ-orleans.fr
AF: Universite d'Orleans, BP6749, Orleans, 45067 France
AU: Gomez, J
EM: gomez@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, Paris cedex 05, IdF 75252 France
AB: Central Asia boasts one of the world's densest regions sampled for paleomagnetic data thanks to numerous sections of well-exposed rocks possessing stable remanent magnetizations. Such is the case for the Tarim craton, which is represented by a quasi-continuous time sequence of paleomagnetic poles since the Permo-Carboniferous. Most of these poles are derived from studies demonstrating positive fold and-or reversal tests, with N equal to or greater than 6 sites or 50 samples. Samples collected from Permo-Carboniferous rocks usually have reverse polarities, and samples collected from Cretaceous rocks usually have normal polarities, consistent with the geomagnetic polarity time scale. Despite the apparent excellent quality of the paleomagnetic data from Tarim, they impose geologically unrealistic tectonic displacements when compared to the Eurasian and-or Indian APWPs. This leads to the Tarim APWP paradox: is there a problem (inclination shallowing, overprinting, etc.) with the plentiful Tarim data, or is the Eurasian APWP not representative of the land east of the Ural Mountains? If the latter is true, then previous tectonic reconstructions must be reconsidered. If the former is true, then when/how can we rely on the paleomagnetic data? We present arguments showing that both scenarios have their pros and cons.
DE: 8110 Continental tectonics--general (0905)
DE: 8155 Plate motions--general
DE: 8157 Plate motions--past (3040)
DE: 1525 Paleomagnetism applied to tectonics (regional, global)
DE: 1540 Rock and mineral magnetism
SC: Union [U]
MN: 2004 AGU Fall Meeting