mohammad javad khanzadi

Sirvan historical site is located in Sarāb Kalān village in northern area of Ilam province and according to experts and remains belongs to Sasanian and Early-Islamic periods. The purpose of this research, for the first time, was to investigate the chemical structure of 10 glass fragments (mainly including parts of the body of the vessel) obtained from geoarchaeological studies of this area, using XRF analytical method. The results of analysis show that these samples have been classified in the group of alkaline glass (silica - soda - lime) and according to the ratio of their alkaline elements, vegetable ash (probably local plants) has been used to prepare the glass load. The average weight percentage of silicon oxide is 60.97 with a variance of 15.100 and due to the amounts of aluminum and iron oxides, different sources of silica with low purity have been used in the production of these glasses. Observing variation in amounts of elements in glass lattice and lack of correlation between elements, strengthens the hypothesis of diversity and alteration in primary sources. Also, a comparative study between these samples with the analytical results of glass artifacts belonging to the closest historical sites to Sirvan (Goryeh and Jahangir Dome), indicates that probably the samples of Sirvan are older than these two sites, and trial and error has been played a main role in their production.

According to experts, Sirvan historical site in Ilam province belongs to the Sassanid period or the early Islamic centuries. Despite the archaeological importance of this site, unfortunately, methodical and broad archaeological and archaeometical activities have not been performed. To the systematic investigation of samples obtained from the initial excavations for geoarchaeological studies, 14 potsherds from this site were examined. Concerning this question that what are the main geochemical properties, structural similarities, and differences between these specimens, experimental analysis was done. In order to the elemental and mineralogical description of samples, estimating their firing temperature, and preparing a model for classification of them, chemical composition and mineralogical phases of samples were characterized through X-ray fluorescence (XRF) and X-ray diffraction (XRD) analysis. The standard deviations of the amount of silicon, aluminum, iron, calcium, and magnesium oxides were calculated at 11.527, 3.290, 2.705, 5.887, and 2.087, respectively. High dispersion of the quantity of elements especially for Si and Ca reveals that these samples belong to different workshops, regions, or historical periods with variation in sources and amounts of raw materials and processing steps. in the same geographical area. Moreover, any special model for classification of samples not found, except samples no. S8 and S9 that have similarity in their chemical and mineralogical composition. In addition, the three samples S12, S13, and S14 have completely different chemical and mineralogical characterization and are probably to be imported products. Also in samples with a high amount of the calcium oxide (more than 6%), probably local limestones were used as temper. In general, these samples can be considered as local production (except for the three examples mentioned. Concerning not identifying the clay minerals and presence of calcite (likely primary), diopside, and gehlenite (as firing products), the firing temperature of these samples was estimated between 850 - 900.