Textural Changes in Speleothem Inclusions during Firing: A Useful Tool to Estimate Temperature in Speleothem-Bearing Pottery

Speleothem inclusions have been identified in a ceramic class, ‘flared rim and flat lip’ pottery, that is widespread in the Friuli  – Venetia Giulia and Veneto regions (north-eastern Italy) between the Final Bronze Age and the Early Iron Age. Textural analysis of speleothem inclusions revealed small rounded pores occurring along annual growth laminae, interpreted as the result of partial calcite decomposition during firing. Their size, number and diffusion at increasing temperatures were monitored during a set of firing experiments following heating and cooling rates, soaking times and redox conditions typical of open-firing kilns. The textural features of the speleothem inclusions turned out to represent a powerful thermometric tool to precisely determine firing temperature which, in the case of the ‘flared rim and flat lip’ pottery studied here, reduced the thermal interval to a greater extent than that obtained from mineralogical associations.