RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 8, ES1002, doi:10.2205/2005ES000185, 2006

Method of Study

[27]  It is believed [Khain, 2001] that a new supercontinent, Pangea, had been formed by the end of the Late Paleozoic, which combined all of the major continental blocks, including those composing the basic part of modern North Eurasia. Let us assume (we will return to this point later) that the western part of North Eurasia, including the East European Platform with its pre-Mesozoic foldbelts (we use the term "Stable" Europe for this region in the text that follows) and the Siberian Craton, had not experienced any movements relative to each other during the post-Paleozoic time. In this case we can attempt to verify the dipole type of the geomagnetic field at the boundary between the Paleozoic and Mesozoic by way of comparing the paleomagnetic poles of the Siberian Platform and "Stable" Europe, of the same or closely similar age. The absence of any significant difference between the compared poles (calculated proceeding from the dipole law) was supposed to confirm the dipole character of the Earth's magnetic field in the respective interval of time. In the opposite case the dipole character of the geomagnetic field at the Paleozoic-Mesozoic boundary would be doubtful. The observed differences between the positions of the paleomagnetic poles could be compared with the expected one, proceeding from the assumption of some or other relationships between the zonal non-dipole (quadrupole and/or octupole) and dipole sources. This comparison was supposed to allow us to estimate the potential contribution of the non-dipole components to the geomagnetic field at the Paleozoic-Mesozoic boundary. We believed it most convenient to chose the time interval corresponding to the Permian-Triassic boundary (with an age of about 250 Ma) for the comparison of the Siberian and European paleomagnetic poles. We preferred to use this time interval because, first, there is a significant number of high-quality paleomagnetic data for the rocks of this age and, secondly, this time interval is believed [Torsvik and Van der Voo, 2002] to have been marked by the highest non-dipole content of the geomagnetic field (TAF) for the last 300 Ma.


RJES

Citation: Veselovskiy, R. V., and V. E. Pavlov (2006), New paleomagnetic data for the Permian-Triassic Trap rocks of Siberia and the problem of a non-dipole geomagnetic field at the Paleozoic-Mesozoic boundary, Russ. J. Earth Sci., 8, ES1002, doi:10.2205/2005ES000185.

Copyright 2006 by the Russian Journal of Earth Sciences

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