Thermogravimetric and Differential Scanning Calorimetric Analysis of Archaeological Pottery Samples from Keeladi, Tamil Nadu, India

Ancient pottery samples from Keeladi, Tamil Nadu, dated to the 6 ^th century BCE, were analyzed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The main objective of this study is to investigate the thermal behavior of the samples and to evaluate the physical and chemical transformations that take place during heating. The findings highlight a clear technological progression from simple open-firing practices to more controlled, high-temperature kiln technology. The samples vary from lower fired earthenware fired below 700°C to high-temperature ceramics fired between 900-1050 °C, demonstrating a technological evolution toward dense, high-performance ceramics in Keeladi’s pottery tradition. These results indicate a more pronounced vitrification process, with qualities comparable to those seen in modern high-performance ceramics. The red colour in the pottery is attributed to hematite mineralogy, while the dual-redox nature of Black-and-Red Ware corresponds to limited-oxygen reduction in the core during the production stage is an example for well managed variable atmosphere firing. Altogether, the results identify Keeladi as an advanced pottery production center with notable kiln control, raising an important question about how this 2500-year-old community achieved such high firing temperatures.