Affiliation: | 1.Paléomagnétisme, Institut de Physique du Globe de Paris, PRES Sorbonne Paris Cité and Centre National de la Recherche Scientifique,Saint-Maur cedex,France;2.Geological Institute,Bulgarian Academy of Sciences,Sofia,Bulgaria;3.Department of Geology and Geography,Sofia University,Sofia,Bulgaria;4.National Institute of Geophysics, Geodesy and Geography,Bulgarian Academy of Sciences,Sofia,Bulgaria;5.Department of Meteorology and Geophysics, Physics Faculty,Sofia University,Sofia,Bulgaria |