Simo Spassov Dr. sc. nat.
Section du Magnétisme Environnemental
Centre de Physique du Globe	Telephone:  +32 60 395 424
Institut Royal Météorologique	Facsimile:   +32 60 395 423
Dourbes  -   5670	e-mail:            simo.spassov@oma.be
Belgium

• Archaeomagnetism

Since September 2003, I am working in the European research project AARCH (Archaeomagnetic Applications for the Rescue of Cultural Heritage). Here you will find a link to the AARCH workshop 3 in Madrid from 18.03. - 21.03. 2005.
The temporary record of the Earth's magnetic field intensity in Greece is solely based on material from archaeological sites. Data from historical lava flows on Santorini would complete the Greek data set and provide additional control points. Within this frame, eight lava flows ranging in time from 46 AD until 1950 AD and volcanic clasts from the Minoan eruption 1640 BC were sampled. Archaeological material from Hellenistic pottery kilns has been sampled, too. Magnetic remanence carrying minerals often alter during thermal treatments, such as during the procedure for determination of the ancient magnetic field. The samples were tested for thermal stability (thermomagnetic analyses of magnetic susceptibility and magnetic remanence). First results show that the lava samples are thermally stable and may be useful for absolute ancient field intensity determination. The archaeological material is thermally stable, too. In a next step the absolute ancient field intensity will be determined using Thellier-Thellier and microwave analysis.

• Application of rock magnetic methods to environmental problems (Airborne particulate matter, pollution monitoring)

• Palaeoclimate / Ecosystem models
  

• Magnetism of loess and palaeosol sediments

My PhD research was  intended to contribute to complex palaeomagnetic and palaeoclimatic questions. It tackled a  major  conflict  in the magnetostratigraphy of Chinese loess/ palaeosol sections: the position  of the Matuyama-Brunhes boundary (MBB). The boundary has been observed  in  the marine oxygen isotope  stage  19  in  a  horizon  which  corresponds  to  an interglacial period.  In  most  of  the  Chinese  loess/palaeosol  sequences, however, this major polarity change has been  observed  in  a  loess  layer, which clearly represents a cold climate interval. This causes  a  large  age discrepancy for the MBB of about 23 to 26 kyr  between  magnetostratigraphic records on land and in the marine realm. The MBB transitional interval  was  investigated  in  detail.  The  observed polarity pattern is characterised by abrupt changes of normal  and  reversed polarities. Different nearby loess sections were considered as  well  as  an ODP record near Japan. In each case the polarity record  was  different.  It was concluded that  the  transitional  polarity  behaviour  rather  reflects complex magnetisation lock-in processes than the Earth's magnetic field. In order to shed  some  light  on  this  problem,  grain  size  fractionated loesses and palaeosols of different weathering and  pedogenetic  degree  were analysed.  Evidence  was  found  for  coexisting  detrital  and   pedogenic remanence carrying components using mainly coercivity  spectra  analysis  in combination with geochemical and other rock magnetic methods. The  different components have been quantified, too. It was further  shown,  that  detrital remanence carriers  were  not  destroyed  during  weathering  and  that  new pedogenic components in palaeosols derive from iron bearing clays  and  other ferruginous silicates. The previous results were used to set up a magnetisation lock-in  model  for loess/palaeosol  sediments.  This  model  was  able  to  explain   the   time discrepancy between marine and continental loess sediments as  well  as  the complicated  transitional  magnetisation  record   in   terms   of   delayed acquisition of magnetic remanence and varying  detrital/pedogenic  remanence contribution.

New book  Environmental Magnetism                                                                                                                                                          Ted Evans and Friedrich Heller give in their recently published book a very comprehensive review of the state-of-the-art of environmental magnetism, covering a broad spectrum of applications.