Valores de efecto reservorio marino para los últimos 5.000 años obtenidos en concheros de la costa atlántica norpatagónica (Golfo San Matías, Argentina)

Abstract

Ten shell-charcoal pairs obtained from archaeological shell-middens along the San Matías gulf (Northern Patagonia, Argentina) were dated by accelerator (AMS) in order to evaluate the local marine reservoir effect -MRE-. The age differences obtained fluctuate between 205 and 358 radiocarbon years from ca. 5.300 to ca. 700 yr BP, not recording any temporal tendency in such time span. Local factors as restricted connection with the open sea or the presence of aged carbonates do not show a visible influence on this effect along the gulf coastline. However it has been detected a possible age offset in relation with the age at death of some shrubs used as fuel. The mean value of age differences, related to reservoir effect, was 266±51 yr. It may be highlighted that this local value is perceptibly lower than the standard mean oceanic one, and would represent a useful age for correcting radiocarbon dates in shells from the abundant archaeological sites present in this area since Middle Holocene times.