Firing temperatures of ceramics from Bulgaria determined by rock-magnetic studies

Abstract

Maximum firing temperatures were determined for a large (198 samples) and variable collection of ceramic sherds from Bulgaria using magnetic susceptibility measurements. The data obtained were combined with the existing archaeological evidences as a first attempt to elucidate the technological development of pottery production in four important Bulgarian archaeological sites – Plovdiv, Pliska, Veliki Preslav and Dragovishtitsa. The results obtained confirm that magnetic susceptibility method is a very effective and precise tool for the determination of ancient firing temperatures, which overall vary from 550°C to 1010°C. Regardless of the great variability of the samples studied (according to their archaeological context, technological characteristics and purpose of usage); the results point out that maximum firing temperatures increase with time. Furthermore, in the earlier periods, firing temperatures of cooking and serving wares are distributed in similar ranges. Thus, the purpose of usage of the vessels has not been decisive about their manufacturing. The technological development in later periods obviously leads to the improvement of the quality of the serving vessels first and of the cooking pots after, but the highest firing temperatures are principally related to serving potteries and especially to the glazed ones. The results obtained for Pliska and Veliki Preslav, located relatively close to each other, indicate that during 10–11 c. CE serving vessels have been produced at higher temperatures in Veliki Preslav in comparison to Pliska but there is no such a difference for the cooking pots. This agrees well with the different status of both settlements at that time. Further expansion of the study by analyzing greater number of well-stratified samples of different types and quality, grouped in type-technology sets could allow finding more precise and common characteristics and trends, which could be compared in synchronous archaeological sites.