New Late Permian paleomagnetic data from Argentina: Refinement of the apparent polar wander path of Gondwana

DOMEIER, M. M.; VAN DER VOO, R.; TOHVER, E.; TOMEZZOLI, R.; VIZÁN, H.; TORSVIK, T.; KIRSHNER,J.

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS

AMER GEOPHYSICAL UNION

Año: 2011 vol. 12 p. 1 - 21

1525-2027

The Late Paleozoic¨CEarly Mesozoic apparent polar wander path of Gondwana is largely constructed from relatively old paleomagnetic results, many of which are considered unreliable by modern standards. Paleomagnetic results derived from sedimentary sequences, which are generally poorly dated and prone to inclination shallowing, are especially common. Here we report the results of a joint paleomagnetic geochronologic study of a volcanic complex in central Argentina. U©Pb dating of zircons has from relatively old paleomagnetic results, many of which are considered unreliable by modern standards. Paleomagnetic results derived from sedimentary sequences, which are generally poorly dated and prone to inclination shallowing, are especially common. Here we report the results of a joint paleomagnetic geochronologic study of a volcanic complex in central Argentina. U©Pb dating of zircons has ¨CEarly Mesozoic apparent polar wander path of Gondwana is largely constructed from relatively old paleomagnetic results, many of which are considered unreliable by modern standards. Paleomagnetic results derived from sedimentary sequences, which are generally poorly dated and prone to inclination shallowing, are especially common. Here we report the results of a joint paleomagnetic geochronologic study of a volcanic complex in central Argentina. U©Pb dating of zircons has ©Pb dating of zircons has yielded a robust age estimate of 263.0 +1.6/−2.0 Ma for the complex. Paleomagnetic analysis has revealed a pretilting (primary Permian) magnetization with dual polarities. Rock magnetic experiments have identified pseudosingle domain (titano)magnetite and hematite as the mineralogic carriers of the magnetization. Lightning induced isothermal remagnetizations are widespread in the low©coercivity magnetic carriers. The resulting paleomagnetic pole is 80.1¡ãS, 349.0¡ãE,A95 = 3.3¡ã,N= 35, and it improves a Late Permian mean pole calculated from a filtered South American paleomagnetic data set. More broadly, this new, high©quality, igneous©based paleomagnetic pole falls between the previously distinct Late Permian segments of the Laurussian and Gondwanan apparent polar wander paths, suggesting that the long©recognized disparity between these  large paleomagnetic data sets may be primarily due to the inclusion of low©quality or systemically biased data.