PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
In the course of the study, the sample thermal cleaning is performed by means of stepped heating to
100 and 200°C and the following cooling in a nonmagnetic space in order to more distinctly reveal specific
features in the inclination (I) behavior.
Fig. 5c-d. Geomagnetic field excursions in column 1157: (c) inclination (I), and (d) inclination(j)
before thermal cleaning (1) and after thermal cleaning to 100˚(2) and 200˚(3).
Figure 5с shows the I4 C absolute age measured with the help of acceleration mass-spectrometry
(Levitan et al., 1999). The average sedimentation rate is 45 cm per 1000 years according to column 1157.
Consequently, the anomalous I values at depths of 75 and 200 cm should be dated as approximately 2200
and more than 4000 years old, respectively. Since the amplitude of variations at these depths exceeds 60° (it
is equal to 130° and 75° according to the nonaveraged values) such inclination variations can indicate that
the geomagnetic field excursion was possible in the considered time interval.
We have indicated (data of column 1157) that the Etrussia-Sterno excursion lasted 100-300 years.
For this time, the geomagnetic pole shifted from the region of the geographic pole to the equator and
backwards, which causes one to pay serious attention to a sharp present-day acceleration of the magnetic pole
displacement and to possible consequences of this displacement.
ACKNOWLEDGMENTS
This work was supported by the Russian Foundation for Basic Research, project no. 06-05-64200a.
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