Geomagnetic field variations as determined from Bulgarian archaeomagnetic data. Part II: The last 8000 years

The knowledge about past secular variations of the geomagnetic field is ach ieved on the basis of archaeomagnetic researches of which the Bulgarian stu dies form an extended data set. In Part I (Kovacheva and Toshkov, 1994), th e methodology used in the Sofia palaeomagnetic laboratory was described and the secular variation curves for the last 2000 years were shown. In Part I I (this paper), the basic characteristics of the prehistoric materials used in the archaeomagnetic studies are emphasised, particularly in the context of the rock magnetic studies used in connection with palaeointensity deter minations. The results of magnetic anisotropy studies of the prehistoric ov ens and other fired structures are summarised, including the anisotropy cor rection of the palaeointensity results for prehistoric materials, different from bricks and pottery. Curves of the direction and intensity of the geom agnetic held during the last 8000 years in Bulgaria are given. The availabl e directional and intensity values have been used to calculate the variatio n curve of the Virtual dipole moment (VDM) for the last 8000 years based on different time interval averages. The path of virtual geomagnetic pole (VG P) positions is discussed.