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Archaeomagnetism |
Geophysics Department, L. Eötvös University, H-1083 Budapest, Ludovika tér 2, Hungary
The first archaeomagnetic dating in Hungary was made using a reference inclination curve derived by interpolation between three inclination curves then available from continental Europe, namely from France, Bulgaria and the Ukraine. As the corresponding declination curves could not be interpolated with confidence, all three declination curves were used only for an estimation of the time interval to which the measured declinations might be assigned. As data accumulated it became feasible for dating to be made exclusively on the basis of archaeomagnetic and direct observational results for Hungary. The results now cover the last 2000 years with relatively short gaps (sixth and thirteenth centuries AD), for which data interpolation is plausible. The variation of inclination is fairly sinusoidal and well resolved. It exhibits two maxima (c. 70°) at approximately AD 800 and AD1500 and three minima at about AD300 (c. 58°), AD 1300 (c. 55°) and in the twentieth century (c. 62°). Although the variation of the declination is twice as large as that of the inclination, the declination record has inherently less resolution (dD = dI/cosI > dI). Approximately zero declination values during the first half of the first millennium AD were followed by westerly values during the sixth to eighth centuries (c. 10°). It appears that by AD 900 the declination was already easterly and rapidly increasing until AD 1000 when it peaked with a value over 20°E. A newly discovered feature is a short oscillation beginning with 16° at AD 1300 and ending with 16.5° at AD 1600 during which the declination became westerly with a minimum of –10° in the first half of the fifteenth century. From AD 1600 on the declination rapidly decreased and described a negative half circle between about AD 1620–30 and 1950 with a minimum of –18° at AD 1800. The general pattern of the directional secular variation for Hungary is in agreement with that for France, Sicily, Britain, the Ukraine and the Balkans.
