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
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.
The application of rock magnetic methods in environmental sciences is appreciated because of non-destructive and fast measurement schemes. Magnetic methods offer the great advantage that low concentrations (in the order of ppm) of ferromagnetic phases can be detected, identified and quantified without costly sample preparation and within short measurement time. Iron is one of the most common elements in the Earth's crust. In combination with oxygen and sulphur it forms magnetic minerals, which occur to a greater or lesser extent universally. Nanometre sized particles are of particular interest because they occur in great quantities, implying a large surface area. Due to these properties, nanoparticles can provoke biological reactions itself or act as a vehicle for other toxic components. Iron oxides and sulphides have excellent adsorbent properties, which attract not only heavy metals but also organic contaminants and even radioactive pollutants. Since, however, magnetism is often not directly related to the pollution source, the magnetism proxy often cannot easily be understood in terms of pollution. I am interested in the calibration of the environmental tool "rock magnetism" and in the relationship between surface properties of magnetic minerals and their magnetic structures. In this context, the magnetic properties of urban particulate matter (PM) were analysed. Two magnetic components with well defined magnetic properties have been identified and quantified in samples of different pollution degree. The magnetic results were compared with independent chemical investigations and are in excellent agreement.
Natural and anthropogenic aspects have to be considered for the prediction of future climate scenarios. Palaeoclimatic records offer the unique possibility to study climate without anthropogenic influence. Natural variability, different states and the response of climate to external changes (e.g. closure of the Isthmus of Panama, uplift of the Tibetan Plateau) can be explored. This information can be used to extend the present climate record and provide longer time frames for evaluating the significance of global warming in recent times. I am interested in constructing an ecosystem model for loess/palaeosol sediments. The two states (loess and palaeosol) may be investigated in detail. Weathering, pedogenetic and diagenetic processes, as well as vegetation and climatic influence can be studied intensively. Rock magnetic, sedimentological and geochemical methods may used to characterise the lithological/palaeoclimatic relations and climate feedback processes.
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.
S. Spassov, F. Heller, M.E. Evans, L.P. Yue and Z.L. Ding,
Geomagnetic reversals in the sediments of the Central Chinese Loess
Plateau, Geologica Carpathica, 51, pp. 197, 2000.
S. Spassov, F. Heller, M.E. Evans, L.P. Yue and Z.L. Ding, The
Matuyama/Brunhes geomagnetic polarity transition at Lingtai and Baoji,
Chinese Loess Plateau, Physics and Chemistry of the Earth, 26, pp.
A. Tsatskin, F. Heller, T. S. Gendler, E. I. Virina, S. Spassov, J. Du
Pasquier, J. Hus, E. A. Hailwood, V. I. Bagin and S. S. Faustov, A new
scheme of terrestrial paleoclimate evolution during the last 1.5 Ma in
the western Black sea region: integration of soil studies and loess
magnetism, Physics and Chemistry of the Earth, 26, pp. 911-916,
S. Spassov, Loess magnetism, environment and climate change on the
Chinese Loess Plateau, Doctoral Thesis, Diss No. 14976, ETH
Zürich, Switzerland, 2002.
S. Spassov, F. Heller, M.E. Evans, L.P. Yue and T. v. Dobeneck, A
lock-in model for the complex Matuyama-Brunhes boundary record
of the loess/palaeosol sequence at Lingtai (Central Chinese Loess
Plateau) Geophysical Journal International, 155, pp. 350-366, 2003.
S. Spassov, F. Heller, R. Kretzschmar, M.E. Evans, L.P. Yue and
D.K. Nourgaliev, Detrital and pedogenic magnetic mineral phases in
the loess/palaeosol sequence at Lingtai (Central Chinese Loess Plateau),
Physics of the Earth and Planetary Interiors, 140, pp. 255-275, 2003.
S. Spassov, R. Egli, F. Heller, D.K. Nourgaliev and J.A. Hannam,
Magnetic quantification of urban pollution sources in atmospheric particulate
matter, Geophysical Journal International, 159, pp. 555-564, 2004.
Gendler, T.S., Heller, F., Tsatskin, A., S. Spassov, Du Pasquier, J., and S.S.
Faustov, Roxolany and Novaya Etuliya - Key sections in the western Black Sea
loess area: magnetostratigraphy, rock magnetism and paleopedology,
submitted to: Quaternary Research, 2004.
S. Spassov, F. Heller, T.S. Gendler, V.I. Bagin, E.I. Virina, S.S.
Faustov, J. Hus, E.A. Hailwood and A. Tsatskin, Magnetism of the
loess/palaeosol sequence at Novaya Etuliya, Moldavia, European
Geophysical Society, XXIV General Assembly, The Hague, The
Netherlands, 19. - 23. April 1999. (oral presentation)
T.S. Gendler, F. Heller, S. Spassov, J. Hus, E.I. Virina, E.A.
Hailwood, A. Tsatskin, V.I. Bagin, E.A. Haliulina and S.S. Faustov,
Para- and ferromagnetic minerals in loesses and palaeosols at Novaya
Etuliya, Moldavia: Archive of Quaternary paleoenvironmental change,
European Geophysical Society, XXV General Assembly, Nice, France, 25.
29. 4. 2000 (poster)
S. Spassov, F. Heller, M.E. Evans, Yue, L.P. and Z.L. Ding, Geomagnetic
Polarity Transitions at Lingtai and Baoji, Central Chinese Loess
Plateau, European Geophysical Society, XXV General Assembly, Nice,
France, 25. - 29. 4. 2000 (poster)
A. Tsatskin, F. Heller, T.S. Gendler, E.I. Virina, S. Spassov, J. du
Pasquier, J. Hus, E.A. Hailwood, V.I. Bagin and S.S. Faustov, A new
scheme of terrestrial paleoclimate evolution during the last 1.5 Ma
from the Western Black Sea region: integration of soil studies and
loess magnetism, European Geophysical Society, XXV General Assembly,
Nice, France, 25. - 29. 4. 2000. (poster)
S. Spassov, F. Heller, M.E. Evans, L.P. Yue and Z.L. Ding, Geomagnetic
reversals in the sediments of the Central Chinese Loess Plateau, New
Trends in Geomagnetism VII, Paleo- Rock and Environmental Magnetism,
19. bis 25. 06. 2000, Moravany, Slovakia. (oral presentation)
S. Spassov, High resolution record of geomagnetic polarity events at
Lingtai, China, Kolloquium Institut für Geophysik, ETH Zürich, 30. 06.
2000, Zürich, Switzerland. (oral presentation)
S. Spassov, R. Egli and F. Heller, A new method for IRM
analysis, MAG-NET (TMR-network) workshop, Zürich 2000.
S. Spassov, T. v. Dobeneck, F. Heller, M.E. Evans and L.P. Yue, Delayed
lock-in of the Matuyama-Brunhes boundary in the loess/palaeosol sequence
at Lingtai (Central Chinese Loess Plateau), European Geophysical
Society, XXVI General Assembly, Nice, France, 25. - 30. 3. 2001. (oral
S. Spassov, Kretzschmar, F. Heller, M.E. Evans and L.P. Yue, Evidence
for pedogenic magnetite in loess and palaeosols? EGS02-A-02544,
European Geophysical Society, XXVII General Assembly, Nice, France,
21.-26. April 2002. (poster)
F. Heller, S. Spassov, M.E. Evans, L.P. Yue and T. v. Dobeneck, Delayed
lock-in of the Matuyama-Brunhes geomagnetic polarity boundary in the
loess/palaeosol sequence at Lingtai (Central Chinese Loess Plateau),
International workshop on fundamental rock magnetism and environmental
applications, Erice, Sicily, 26. 06. - 01. 07. 2002.
S. Spassov, Loess magnetism, environment and climate change on the
Chinese Loess Plateau, oral presentation at the Institute of Geography
at the University of Bern, Switzerland, 21. 01. 2003.
R. Egli and S. Spassov, A novel method for the identification and
characterisation of magnetic sources in sediments, EAE03-J-04970,
EGS-AGU-EUG Joint Assembly, Nice, France, 06. - 11. April 2003.
S. Spassov, R. Egli, F. Heller and D.K. Nourgaliev, Discrimination of
atmospheric particulate matter sources with magnetic methods,
EAE03-J-00846, EGS-AGU-EUG Joint Assembly, Nice, France,
06.-11. April 2003. (poster presentation).
R. Egli, S. Spassov and F. Heller, Coercivity distribution of soft-magnetic
components and their occurrence in sediments and sedimentary rocks, AGU
fall meeting, 8 - 12 December 2003 San Francisco, CA. GP41B-0049
S. Spassov, R. Egli and F. Heller, Magnetic quantification of road traffic
pollution in atmospheric particulate matter: a new approach, AGU fall
meeting, 8 - 12 December 2003 San Francisco, CA. GP41B-0048 (poster
R. Egli, S. Spassov, Baster, I., Sturm, M., Heller, F., Kondopoulou, D.,
Occurrence and magnetic properties of magnetosomes in lake sediments
and implications for environmental magnetism, EGU04-A-02206, EGU 1st
General Assembly, Nice, France, 25-30 April 2004 (oral presentation).
Spassov, S., Egli, R., Zananiri, I., De Marco, E., Lüscher, P., Kretzschmar, R.,
A detailed chemical and rock magnetic investigation of a soil profile in
Switzerland, EGU04-A-06299, EGU 1st General Assembly, Nice, France,
25-30 April 2004 (oral presentation).
Spassov, S., De Marco, E., Zananiri, I., Kondopoulou, D., Magnetic properties
of volcanics and archaeological material: Implications for palaeointensity
determination, EGU04-A-05102, EGU 1st General Assembly, Nice, France,
25-30 April 2004 (poster presentation).
Spassov, S., Hus, J., Egli, R., Heller, F. and M.E. Evans, The concept of linear
unmixing - a key for interpreting environmental magnetic signals, GP34A-01
AGU Fall Meeting, San Francisco, USA, 13-17 December 2004.
Kondopoulou, D., Polya, D., Spassov, S., Atzemoglou, A., Zananiri, I. and
B. Maher, Application of environmental magnetic techniques in detecting
nanoparticle contamination. British-Greek Partnership in Science and
Spassov, S., Introduction to Environmental magnetism (lecture for graduate
students), Aristotle University of Thessaloniki, June 2004.
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.
|last updated 10.02.2005 firstname.lastname@example.org|