The connection between geomagnetic secular variation and climate changes in Eastern Europe during Holocene
|Location||International Geological Congress,oslo 2008|
|Holding Date||20 September 2008|
One of the possible mechanisms of the causes of short-term climate changes and geomagnetic field variations is a matter of discussions of numerous papers of Prof. V.Bucha. It has been found that changes in the position of the geomagnetic pole play an important role in temperature fluctuations in the northern hemisphere. The position of the geomagnetic pole as a centre of the auroral oval and solar corpuscular radiation (and geomagnetic activity) causes the changes in the atmospheric circulation, including sudden intrusions of arctic air in Europe. Adopting this as a working hypothesis, variation of the geomagnetic pole position over hundreds up to one or two thousands of years should also be reflected in long-term variations of climatic situation.
In order to verify this hypothesis we analyzed new data, obtained during palaeomagnetic study of lake sediments in North Europe, together with archaeomagnetic and palaeomagnetic data from existing Databases (archaeomagnetic directional and palaeosecular variation) and palaeotemperature variation. Palaeoclimatic reconstructions of the Late Weichselian and Holocene were calculated by V. Klimanov using the information-statistical analysis methods. More then 40 palaeoclimatic curves from different regions of Eastern Europe serve as a background for combine diagram which reflect main landscape-climatic characteristics during this period. Palaeomagnetic study has been undertaken for Late Quaternary deposits from 43 outcrops and cores (about 12000 samples) located on the territory within 59-70 N and 28-40 E.
The sediments are represented by glaciolacustrine, glaciomarine, marine and lake deposits with sedimentation rate mainly 0.1-0.3 cm/yr. As a result, composite regional magnetostratigraphical scheme of palaeosecular variation for north-western part of Russia with the radiocarbon ages of the main peaks for the last 13 kyr has been set up. Detailed records of declination and inclination variations correlate with palaeomagnetic data from Finland and Western Europe. Analyses of the geomagnetic pole position during the Late Weichselian and Holocene suggest that alteration of cold and warm intervals in northern and north-eastern Europe are connected with geomagnetic secular variations. The change of stadial and interstudial stages depends on position of the geomagnetic North Pole (as a centre of the auroral oval) relative to the geographic pole.
In the situation when geomagnetic pole approaches to or recedes from Northern Europe, the temperature in Eastern and Northeastern Europe increases or decreases. The main causes of long-term climatic changes are assumed to be astronomic factors such as fluctuation of the Earths orbital parameters, while one of the probable causes of climate changes in the periods of few hundred - thousands years are changes of geomagnetic pole position. This regularity is confirmed by archaeomagnetic data from Ukraine for the last 5 kyr.