Shell we cook it? An experimental approach to the microarchaeological record of shellfish roasting

Abstract

In this paper, we investigate the microarchaeological traces and archaeological visibility of shellfish cooking activities through a series of experimental procedures with direct roasting using wood-fueled fires and controlled heating in a muffle furnace. An interdisciplinary geoarchaeological approach, combining micromorphology, FTIR (in transmission and ATR collection modes), TGA and XRD, was used to establish a baseline on the mineralogical transformation of heated shells from aragonite to calcite and diagnostic sedimentary traces produced by roasting fire features. Our experimental design focused on three main types of roasting procedures: the construction of shallow depressions with heated rocks (pebble cuvette experiments), placing shellfish on top of hot embers and ashes (fire below experiment), and by kindling short-lived fires on top of shellfish (fire above experiments). Our results suggest that similar shellfish roasting procedures will largely create microstratigraphic signatures of anthropogenically reworked combusted material spatially Bdisconnected^from the actual combustion locus. The construction of shallow earth ovens might entail an increased archaeological visibility, and some diagnostic signatures of in situ hearths can be obtained by fire below roasting activities. We also show that macroscopic visual modifications and mineralogical characterization of discarded shellfish might be indicative of specific cooking activities versus secondary burning.

Experimental Approaches to Archaeological Fire Features and Their Behavioral Relevance

“…These are artifacts or sediments altered because of fire temperatures. Depending on the temperature threshold, such heating can result in important structural and mineralogical transformations (Aldeias et al 2016a(Aldeias et al , 2016bChu et al 2008;Elbaum et al 2003;Maki, Homburg, and Brosowske 2006;Schmidt 2013;Schmidt et al 2013;Stiner et al 1995;Toffolo and Boaretto 2014;Weiner et al 2015). Therefore, thermally altered artifacts (bones, lithics, shells, seeds, etc.…”

“…Of particular interest is the identification of syndepositional (i.e., after formation and before burial) human interactions with fire residues, as such data can give us information on space use, maintenance activities, and, at times, fire functions. For instance, in our experimental work with hearths used for roasting shellfish, Aldeias et al (2016b) showed that spreading and dumping of fire residues outside the cooking area was an essential step in the cooking procedures. Such actions resulted in the absence of a microstratigraphy associated with intact hearths, which in this case would not be due to poor preservation of the fire features but because removal of combustion residues was an intentional activity that directly related to hearth use.…”

Freshwater fishing at the Neolithic site of Rakushechny Yar

“…Also artefacts, such as a broken vessel, fragments of different vessels, polishing stones, and some bone tools, were also found. On the basis of experimental studies (e.g., Aldeias, Gur‐Arieh, Maria, Monteiro, & Cura, ), archaeologists assume that the pit might have been used for heating Unio sp. shells (Dolbunova et al, in print).…”

The significance of aragonite in the interpretation of the microscopic archaeological record

“…A similar approach was used by Villagran (2014) with Anomalocardia brasiliana (venus clam) shells. Aldeias, Gur‐Arieh, Maria, Monteiro, and Cura (2019) characterized the recrystallization of aragonite into calcite upon heating in different species to investigate shellfish roasting from an experimental standpoint and with the aid of FTIR, µFTIR, XRD, and micromorphology. Karkanas et al (2019) characterized with µFTIR the mineralogy of fossil aragonitic oolites embedded in the construction material of a Late Bronze Age pottery kiln in Greece to distinguish unaltered areas (aragonite) from areas affected by elevated temperatures (calcite).…”