Reservoir Effect of Coastal Waters off Western and Northwestern Galicia

Abstract

Differences in the radiocarbon ages of closely associated marine mollusk shells and terrestrial material(charred wood or bones) from several Galician archaeological contexts are significant from the Iron Age to Medieval times. ΔR values show high variability, ranging from 280 70 to 270 40 14C yr. The set of ΔR values also presents a strong positive peak (ΔR = 270 40 14C yr) at 860 90 BP, which matches another peak found for western Portuguese coastal waters. The data obtained, namely the negative or close to zero ΔR values, suggest that the reduced offset between atmospheric and surface water 14C content is due to the existence of a strong stratification of the water column and environmental factors in the Galician ras during the Iron Age and the Medieval period.