Mineralogy, Fe-57 Mossbauer spectra and magnetization of chalcolithic pottery

Three chalcolithic pottery sherds, paint removed from the surface of each sherd, and an unheated red pigment (Tell-Halaf culture, Turkey) were analysed within the frame of archaeometric studies using mineralogical methods, (57)supercript stopFe Mossbauer spectroscopy, magnetization and rotational hysteresis data. From mineralogical results, the individual minerals forming the cores of the sherds were determined. It was found that the sherds are lime-rich. High temperature X-ray analysis on comparable Ca-rich material showed that the established composition is consistent with a firing temperature of 750-950 degrees C. Apart from the pigment, each Mossbauer spectrum of Fe-bearing components consists of dominating paramagnetic doublets, arising mostly from silicate phases, and of a six-line pattern with reduced intensity, due to ferri- and/or antiferromagnetic Fe-oxide phases. For three samples, an Fe3+ silicate component of the spectra is clearly dominating, which points to oxidizing conditions during firing. For the others Fe2+ and Fe3+ components occur in about equal intensities. For the pigment, the magnetic sextet is of similar intensity to the Fe3+ silicate component. From magnetic analysis of ferrimagnetic phases it follows that a low percentage of particles of solid solutions gamma-Fe2O3 - Fe3O4 exist, probably in part <= 0.1 mu m in diameter. The ferrimagnetic particles of at least one paint are probably covered by a thin layer of hematite as found from rotational hysteresis data. An attempt is made to draw conclusions from the experimental results, regarding the firing conditions of the sherds and paints.

@article{id135,
  author = {Keller, R. and Masch, L. and Pohl, J. and Schmidbauer, E.},
  doi = {10.1007/s00269-005-0459-6},
  journal = {Physics and Chemistry of Minerals},
  language = {en},
  number = {3},
  pages = {165-174},
  title = {Mineralogy, Fe-57 Mossbauer spectra and magnetization of chalcolithic pottery},
  volume = {32},
  year = {2005},
}

%O Journal Article
%A Keller, R.
%A Masch, L.
%A Pohl, J.
%A Schmidbauer, E.
%R 10.1007/s00269-005-0459-6
%J Physics and Chemistry of Minerals
%G en
%N 3
%P 165-174
%T Mineralogy, Fe-57 Mossbauer spectra and magnetization of chalcolithic pottery
%V 32
%D 2005