Iron and bronze production in Iron Age IIA Philistia: new evidence from Tell es-Safi/Gath, Israel

Physical and mineralogical properties of experimentally heated chaff-tempered mud bricks: Implications for reconstruction of environmental factors influencing the appearance of mud bricks in archaeological conflagration events

“…3000 years old fired pottery is only partial (apparent by the presence of an OH band at 3620 cm −1 , while the OH band at 3690 cm −1 is absent). Similar observations were made by Berna et al (2007), Eliyahu-Behar et al (2012, Gur-Arieh et al (2013, 2014 and Friesem et al (2014a) who worked in various locations in Israel, Uzbekistan and Greece, where different types of soils and sediments occur. They all point to the same spectral changes in heated clay minerals, and show that these spectral changes are preserved for thousands of years.…”

“…6 in Berna et al, 2007; see also Eliyahu-Behar et al, 2012;Shoval et al, 2011). Previous studies conducted calibration of spectral changes to clay minerals under oxidizing conditions only (Berna et al, 2007;Eliyahu-Behar et al, 2012;Shoval et al, 2011;Gur-Arieh et al, 2013;Friesem et al, 2014a). They identified the spectral parameters that allow approximation of heating temperature, to be the absence of absorbance bands of structural water (especially the 3690 cm −1 band) when heating occurs above 500°C, lowering of the absorbance bands at 535 and 913 cm −1 , and a gradual shift of the main absorbance band from 1035 to 1084 cm −1 with increasing temperature.…”

“…Specifically, we identify the main component of clay in the sediment used for preparation of experimental mud bricks to be montmorillonite (see in comparison to Fig. 6 in Berna et al, 2007; see also Eliyahu-Behar et al, 2012;Shoval et al, 2011). Previous studies conducted calibration of spectral changes to clay minerals under oxidizing conditions only (Berna et al, 2007;Eliyahu-Behar et al, 2012;Shoval et al, 2011;Gur-Arieh et al, 2013;Friesem et al, 2014a).…”

“…The same approach was also deployed in pottery studies (e.g., Shoval et al, 2011). These studies showed that infrared spectroscopy enables to distinguish between heated and unheated clay, and even determine rough estimates of temperature ranges (Berna et al, 2007;Eliyahu-Behar et al, 2012;Friesem et al, 2014a;Gur-Arieh et al, 2013). We note that thermoluminescence is also a technique suitable for reconstruction of temperature from heated clay-based materials, but relative to infrared spectroscopy it is more time consuming and expensive.…”

“…Clay minerals are known from previous studies to be effective recorders of firing temperature. For example, in heat-related mud-based industrial/ domestic installations such as ovens, furnaces, and where metallurgical activities took place, researchers were able to reconstruct use temperatures through infrared spectroscopy (e.g., Eliyahu-Behar et al, 2012;Gur-Arieh et al, 2013). The same approach was also deployed in pottery studies (e.g., Shoval et al, 2011).…”