Stable isotope and multi-analytical investigation of Monte da Cegonha: A Late Antiquity population in southern Portugal

This study presents for the first time the diet of a Late Antiquity population in southern Portugal (Civitas of Pax Julia), from the Roman villa of Monte da Cegonha (predominantly 7th century CE). Stable isotope analysis (δ13C, δ15N, δ18O, 87Sr/86Sr) of human and faunal bone collagen and apatite was conducted in order to understand the influence of Roman subsistence strategies on the way of life of rural inhabitants of the area of Pax Julia and to explore their diet (types of ingested plants, amount of animal resources, terrestrial versus marine resources). X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR) analyses were used to determine the degree of bone diagenesis and assess the reliability of the bone stable isotopic composition for palaeodietary reconstruction. Anthropological analysis revealed a cariogenic diet, rich in starchy food and carbohydrates, in at least in two individuals based on the frequency of dental caries. Collagen and apatite carbon isotopic analysis suggested that C3 plants were the basis of the population's diet, complemented with some terrestrial meat and its by-products as reflected by the observed bone collagen nitrogen isotopic composition. Moreover, whilst the fairly low apatite-collagen spacing recorded in some skeletons (at around 4‰) may have been due to freshwater organisms intake, the relatively low nitrogen values observed indicate that this consumption did not occur very often, unless in the form of fresh fish of low trophic level or fish sauces. There were no significant differences in isotopic values depending on gender or burial type. Strontium and oxygen isotopic composition of bone apatite revealed a sedentary community, with the exception of a male individual who probably did not spend his childhood in Monte da Cegonha.

Exploring chalcolithic diet and mobility of humans and animals from Perdigões site

Chalcolithic diet at Perdigões (Reguengos de Monsaraz) was investigated using stable carbon and nitrogen isotope analysis of human bone collagen. Strontium isotopes of faunal dental enamel were used to establish the site local range and to distinguish the presence of non-local individuals. ATR-FTIR and EA analysis were used to determine the degree of bone diagenesis and to evaluate the reliability of the stable isotopic composition for paleodietary reconstruction. The individuals from which paleodietary results were obtained had a diet based on C3 terrestrial resources and some animal protein. Data from Perdigões site, was compared with the published data from other Iberian Chalcolithic populations. Site comparison revealed that diet through Iberian Peninsula have mainly maintained terrestrial dietary focus consistent with animal husbandry and farming on C3 plants with occasional intake of freshwater or marine resources. Strontium isotopic composition of enamel revealed that some of the individuals from Perdigões site were non-local; Resumo: A dieta de indivíduos do período Calcolítico dos Perdigões (Reguengos de Monsaraz) foi investigada através de análise de isótopos estáveis de carbono e azoto no colagénio ósseo. Isótopos de estrôncio do esmalte dentário de fauna foram utilizados para estabelecer o sinal local dos Perdigões, permitindo distinguir a presença de alguns indivíduos e fauna não-locais. A avaliação da diagénese óssea foi efectuada através de análises realizadas com analisador elementar e com ATR-FTIR, de forma a validar dos resultados isotópicos obtidos. Os indivíduos para os quais foi possivel obter resultados isotópicos de carbono e azoto apresentam uma dieta baseada em recursos terrestres, plantas C3, e alguma proteína animal. A comparação efectuada com outros sitios arqueológicos da Peninsula Ibérica revelaram que a dieta das populações é sobretudo feita à base de plantas C3, com ingestão de alguma proteina animal e ingestão ocasional de produtos marinhos ou provenientes de água doce.