Estudio experimental de alteración térmica sobre exoesqueletos de moluscos marinos (nacella magellanica) y sus implicancias para la interpretación de conjuntos arqueomalacológicos de concheros en patagonia argentina

The results of the experimental program on current calcareous exoskeletons of Nacella magellanica (Patellidae, Gasteropoda) are presented. This species of mollusc is one of the main that composes the archaeological shell middens in continental Patagonia argentine. We sought to obtain evidence of diagnostic features and modifications generated on the exoskeletons as a consequence of the thermal exposure process. Different samples were submitted to controlled burning under laboratory conditions in a muffle with digital thermocouple to obtain greater control over temperatures (from 0°C to 700°C). Structural, chromatic and textural analysis of samples exposed to heat were carried out. A first approach to the application of the indicators obtained in the experimental program for the analysis and interpretation of arqueomalacologicas assemblages recovered in systematic excavations in shell middens on the northern coast of Santa Cruz, Patagonia Argentina, was performed. This information was complemented with anthracological studies of carbons recovered in the same sites. The analysis of the experimental results and archaeomalacological remains allowed us to estimate that archaeological shells would have been subjected to temperatures of between 300°C and 400°C. Finally, the importance of the experimental approach is highlighted to understand characteristics of materials that make up the archaeological sites.