Variations of angular elements of the geomagnetic field in Europe during the last 24 centuries

The analysis of variations in angular elements of the geomagnetic field during the period since 350 B.C. to the present day according to the findings from the study of thermal magnetization of baked archaeological samples from England, France, and East Europe showed that the key feature in the behavior of the geomagnetic inclination in all three regions is a millennial variation. The trend in the behavior of the inclination of the geomagnetic field can be regarded as a manifestation of a variation with a characteristic time scale of several thousand years. Despite the general likeness of variations in inclination and declination of the ancient geomagnetic field, they also exhibit a noticeable dissimilarity. The paths of the virtual geomagnetic pole reconstructed from the variations of angular elements of the geomagnetic field in East Europe indicate that the geomagnetic polar motion is quasi-cyclic. The duration of the first cycle was about 1000 years, while the second cycle has not been completed due to the change of the motion to the opposite direction in the middle of the XVII century.     

Archeomagnetic studies of ceramics from the archeological monument in Ubeda,Spain

The archaeomagnetic study of the ceramics from the multilayered archeological monument Ubeda in Spain provided the data on the geomagnetic field strength in the period of accumulation of cultural deposits. According to the results obtained for the Ubeda monument of the Bronze Age and the La Motilla Del Azuer multilayer archaeological monument dated to the second millennium BC, the time interval of accumulation of the Ubeda cultural deposits likely spans from the last quarter of the 19th to 18th centuries BC. The sharp decrease in the geomagnetic field strength in the 19th century BC. established against the obtained data is consistent with the archaeomagnetic results for other Eurasian regions and can be used for correlating the ages of various archeological monuments and stages of culture.     

Archaeomagnetic studies of materials from the Gorelyi Les and Ust-Khaita monuments (Eastern Siberia)

Archaeomagnetic studies of materials from archaeological monuments of the Irkutsk and Baikal regions provided new constraints on the geomagnetic intensity variation in Eastern Siberia for the interval from the 5th millennium BC through the 1st millennium AD. Material from the Gorelyi Les and Ust-Khaita multilayer archaeological monuments of the Irkutsk region is dated according to layer depths of deposits. Data on the geomagnetic intensity obtained from archaeomagnetic studies corroborate the validity of this method of dating. It is established that the average level of the geomagnetic intensity smoothly rose in the interval from the 5th millennium BC through the 1st millennium AD, with faster variations being superimposed on this trend. The pattern of the geomagnetic intensity variation is similar to those in other Eurasian regions.     

Determination of the ancient geomagnetic field elements from thermal remanent magnetization corrected for magnetic anisotropy

A method is proposed for correcting the magnetic anisotropy of baked magnetic material from archaeological objects and rocks intended for the study of its magnetization and for gaining data on the angular elements of the ancient geomagnetic field. The application of this correction decreases the spread of individual determinations obtained in studying the sample magnetization from an object and increases the determination accuracy of the average value of the ancient geomagnetic field elements. This, in turn, makes it possible to increase the accuracy of its dating.     

Geomagnetic field intensity in the first millennium BC from data on ceramics of the Los Villares archaeological monument (Spain)

The geomagnetic field variation pattern in the second and third quarters of the first millennium BC is obtained from data on ceramic material sampled in the Los Villares multilayer archaeological monument (Spain). The analysis of available data on the geomagnetic field variation in Spain over the last seven millennia shows that it is similar to the geomagnetic variation pattern observed in other Eurasian regions. The amplitude of the “fundamental” (8000-yr) oscillation (≈20 μT) estimated from the Spain data exceeds significantly its amplitudes in other regions, which supports the previously noted tendency to a westward increase in the amplitude of the fundamental oscillation.     

Archaeomagnetic study of ceramics from the Neolithic Los Castillejos multilayer monument (Montefrio,Spain)

The geomagnetic intensity variation from the middle of the 4th millennium BC to the beginning of the 2nd millennium BC is reconstructed from the archaeomagnetic study of ceramic material taken from 24 layers of the Los Castillejos monument (Montefrio, Spain). The general patterns of the geomagnetic intensity variation reconstructed by studying materials from the Cendres Cave and Los Castillejos monuments (Spain) are similar. The intensity level is revised in the time interval including the minimum of the “fundamental” oscillation of the geomagnetic field; the characteristics of geomagnetic intensity variations whose superposition can provide the intensity variation observed in the study time interval are determined. Constraints on the climate humidity variation over the settlement lifetime are obtained from heating-induced variations in the magnetic susceptibility of the ceramics.     

Geomagnetic Field Record in Ceramics of the Central East European Plain in III–II Millennia B.C.

Izvestiya, Physics of the Solid Earth - Abstract—Archaeomagnetic studies have been carried out for the ceramics from cultural deposits of multilayered archaeological monuments Sakhtysh I and...     

The results of wavelet-analysis of series of archaeomagnetic data on the geomagnetic field intensity

We analyze the results of wavelet analysis of series of archaeomagnetic data on the geomagnetic field’s intensity over the past 7500 yrs performed by Gurarii and Aleksyutin and presented in the paper “Wavelet Analysis of Basic Archaeomagnetic Series of Data on Geomagnetic Field Intensity over the Past 7500 Years” [Gurarii and Aleksytin, 2009]. The results in themselves are beyond question, but their interpretation given in the aforementioned paper is very controversial. Analyzing these results, we arrive at the conclusion that the periods of variations identified reliably (very strongly or identified in a long time interval) lie within certain bands with about 300-, 500-, 750-, and 1600-yr centerlines. The conclusion is drawn on the existence of general regularities in the behavior of geomagnetic field variations.     

Geomagnetic field intensity in the eastern Mediterranean region in the second half of the 1st millennium BC and the beginning of our era

The magnetization of ceramic material manufactured in the eastern Mediterranean is studied. Data on the variation in geomagnetic field intensity in the time interval from the fourth-quarter of the 6th century BC through the 2nd century AD are obtained. The main tendency of the variation in the field intensity until approximately the middle of this interval is its decrease, after which the average intensity level varied insignificantly over the three next centuries. Variations with characteristic times of a few tens to a few hundreds of years are superimposed on the smooth variation in the field intensity approximated by a sinusoid with a period of 1600 yr. The data obtained in this work confirm the previously derived conclusion that short-term intensity variations have been permanently present in the geomagnetic field in the recent millennia.     

Variation of the intensity of the Earth’s magnetic field in Portugal in the 1st millennium BC

The study of magnetization of the ceramic material from 21 archeological monuments of Portugal (the Evora province), dated archeologically from the Bronze Age to the end of the Iron Age has been carried out. For the purpose of more detailed timing of the material from the monuments the method of ceramic age dating on the basis of its porosity has been used. In order to take into account the distorted factors in the determination of the parameters of the ancient geomagnetic field with the aim of the maximal approximation to the actual values the diagnostic features of magnetite weathering have been considered and the level of weathering of the magnetic fraction in the ceramics from archeological monuments has been determined. The data of geomagnetic field-strength variation in the time interval of the 12th century BC to the beginning of the Common Era have been obtained. The field-strength at this time interval varied in the range of 60–90 micro Tesla with the maximal values in the 9th, 8th, and the second half of the 5th to the beginning of the 4th century BC. In addition, the timing of the ceramic material from the urns of the megalithic complex Monte de Tera of the Evora province has been clarified.