Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters off Northern Iberia

Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (mammal bones or charred wood) collected from archaeological contexts in northern Atlantic Iberian coastal areas is used to quantify the marine 14C reservoir effect (ΔR) for the coastal waters off the Cantabrian coast (northern Iberia). For the first time, ΔR values were reliably determined for these coastal waters, and also for the first time a ΔR was calculated for the Late Pleistocene in Atlantic Iberia. Pairs of coeval samples of different carbon reservoirs selected from Upper Paleolithic (Late Pleistocene) and Mesolithic (Early Holocene) contexts yielded ΔR weighted mean values of −117±70 14C yr and −105±21 14C yr, respectively. These values show oceanographic conditions characterized by a reduced offset between atmospheric and surface water 14C contents, suggesting a nonexistent or a very weak upwelling and some stratification of the water column. Similar oceanographic conditions have been recorded in other areas of Atlantic Iberia during the Holocene, such as off Andalusian and northwestern Galician coasts. Results not only provide useful information on environmental conditions but also a framework to obtain more precise and reliable absolute chronologies for the Late Pleistocene and Early Holocene in northern Iberia

Análisis de morteros medievales de dos castillos de Cantabria/España

RESUMEN. En este trabajo se presenta la metodología seguida en el análisis de morteros procedentes de dos castillos medievales, el de Camargo (siglo VIH) y el del Torrejón de Las Henesirosas (siglo XIII), ambos en Cantabria, con objeto de aportar información complementaria a la obtenida en las campañas arqueológicas en ambos asentamientos. La selección de los morteros de cimentación y pavimentación realizada permite que los resultados obtenidos resalten sus diferencias asociadas a las variables de localidad, antigüedad y funcionalidad, lo que ha de servir de base al establecimiento de hipótesis sobre el modo y saber de los procesos constructivos en ambos puntos.ABSTRACT. This work presens the methodological procedure done on the analysis of ancient mortars from two middle-age castles, the one of Camargo (Vlll century) and the Torrejón at Las Henestrosas (XIII century), both in Cantabria. The analysis pretends to get a complementary information to the previous one obtained from the archeological research done at these places. The results obtained from the mortars tested, from foundations or pavem.ent, shoves their differences that can be associted to variables as location, age of construction and utility. The conclusions are a base for later analysis to modeling the construction knowledge in both settings

Protein diagenesis in "Patella" shells: Implications for amino acid racemisation dating

Abstract: The inter- and intra-crystalline fractions of Patella vulgata limpets recovered from archaeological sites in Northern Spain (covering Neolithic, Mesolithic, Magdalenian, Solutrean, and Aurignacian periods) were examined for amino acid composition and racemisation over time. The calcitic apex and rim areas of the shells were found to probably be composed of similar proteins, as the D/L values and amino acids were comparable and varied in the same way with increasing age; however, the mineral structures present in these areas differed. The aragonitic intermediate part of the shell showed a distinctly different amino acid composition and mineral structure. The main protein leaching from the inter-crystalline fraction occurred within the first 6000 yr after the death of the organism. In contrast, the intra-crystalline fraction d comprised of a different protein composition than the inter-crystalline fraction d appeared to behave as a closed system for at least 34 ka, as reflected by the lack of a significant decrease in the amino acid content; however, changes in the amino acid percentages occurred during this period. The concentration of aspartic acid remained almost constant with age both in inter- and intra-crystalline proteins, and its contribution to the total amino acid content increased with age at the expense of other amino acids such as glutamic acid, serine, glycine and alanine. Temperature is thought to play a key role in the amino acid racemisation of P. vulgata and could explain why in the localities belonging to the Gravettian and Solutrean period, which formed during relatively cold conditions, D/L values were similar to those detected in shells from sites formed during the Magdalenian.This paper was made possible by funding from the Spanish Ministry of Science and Innovation projects: HAR2010-22115-C02-01 “La respuesta humana al cambio climático global en una zona litoral: el caso del tránsito al Holoceno en la costa cantábrica (10000-5000 cal BC)”, and HAR2010-22115-C02-02 “Aplicación del análisis de sustancias orgánicas e inorgánicas a la reconstrucción paleoambiental, cronológica y tafonómica de yacimientos arqueológicos del Norte de España”