Elemental analysis of pottery obtained from the historical site of Kohneh Gorab Amlash using Micro-PIXE technique: classification and provenance study

Abstract

The study and measurement of elemental compositions of historical pottery have particular importance. Only by knowing the elemental composition of these historical artifacts can precious information be obtained in various fields such as technology and manufacturing technique, determination of raw materials used in manufacturing and their diversity, the study of trade and exchange, and provenance study of these historical objects. In this article, 14 pieces of glazed artifacts, including the remaining nine dishes and five tiles belonging to the middle of the Islamic period, have been analyzed and examined using the micro-PIXE technique.The pottery studied in this article have been obtained from the second season of archaeological excavation in the ancient site of Kohneh Gorab Amlash in Gilan province in 2021. In the present study, the elemental compositions of the main body, the base glaze, and the surface decorations used in these pieces have been measured using the micro-PIXE analysis for the first time.This study uses elemental analysis to find appropriate answers to related questions. What raw materials have been used to manufacture the main body and glaze of these objects, whether the same raw materials used in the main body and base glaze? What is the resource of the raw materials used as flux or melting materials? Determining the colorant agents and identifying the elements that are responsible for different colors is another question that can be considered as another goal of this research work.Based on the results obtained from the elemental compositions of the main body of the pottery, it can be concluded that different sources of silica have been used in the making of the pottery of Kohneh Gorab Amlash. Elemental analysis depicted three different types of raw materials used in the main body of this pottery to supply silica raw materials. The first group used stonepaste as silica raw materials, and the second and third groups were used clay to silica resources. Also, the results of elemental analysis of the base glaze show that three types of alkali glaze, lead glaze and lead-tin-alkali glaze, can be identified in these studied objects. In addition, the results shows that the flux used in alkaline glazes was prepared from plant ashes.