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.

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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