This paper is devoted to the study of the features of thermoremanent magnetization (TRM) acquisition in brick fragments from a Roman kiln, uncovered by archaeological excavations in the vicinity of the village of Dragovishitisa (Western Bulgaria), in experiments using the Thellier method as modified by Coe. The aim was to determine the magnitude of the geomagnetic field in ~300 AD. Initially, petromagnetic and archeomagnetic studies were carried out in the Paleomagnetic Laboratory of the National Institute of Geophysics, Geodesy and Geography of the Bulgarian Academy of Sciences. Then, experiments using the Thellier-Coe procedure at two cooling rates of samples taking into account the TRM anisotropy were carried out in the Laboratory of the Main Geomagnetic Field and Petromagnetism of the Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. Based on 18 archaeointensity determinations, the average weighted value of the magnetic field B = 56.5 ± 0.8 μT was obtained, corresponding to the archaeological age of 260±20 CE. The dating of 281-342 CE obtained by the archaeomagnetic method is consistent with the archaeological estimate of the kiln operation time. The calculated value of archaeointensity is in satisfactory agreement with the reference values of the magnetic field for Bulgaria and confirms its decrease in the time interval of ~200-300 CE.
O. V. Pilipenko (Wed,) studied this question.