title: A new application of fiber-optic reflection spectroscopy (FORS): characterization of low-temperature alteration of chlorite schist and implications for understanding ancient stone cooking vessels.
abstract: Bulk thermal alterations to chlorite schist occurring at temperatures above 450 °C are traditionally studied using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, or thermogravimetric analysis (TGA), but lower temperature changes that lead to structural and chemical alteration, including changes in oxidation state that are not followed by a crystalline modification, are not detectable using these techniques. In this paper we present the results of the first study to examine the application of fiber-optic reflection spectroscopy (FORS) for the detection and quantification of low-temperature thermal alterations in chlorite schist. Such changes have been observed during research on the thermal behavior of medieval (12th-13th centuries AD) chlorite cooking pots from the archaeological site of Merv, Turkmenistan. FORS was used to investigate these changes, testing the archaeological samples against a model data set of experimental reference specimens. The results demonstrate the potential of FORS for tracking low-temperature thermal alterations and offer the opportunity to examine temperatures attained by ancient chlorite vessels during their past use in cooking activities.
authors.affiliation: Department of Conservation and Scientific Research, The British Museum, Great Russell Street, London WC1B 3DG, UK.
authors.forename: Dvory
authors.initials: D
authors.lastname: Namdar
authors.forename: Giovanni
authors.initials: G
authors.lastname: Verri
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Stacey
authors.forename: Andrew
authors.initials: A
authors.lastname: Middleton
authors.forename: St John
authors.initials: SJ
authors.lastname: Simpson