Improving the 14c dating of marine shells from the Canary Islands for constructing more reliable and accurate chronologies

Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (charred wood or bone) collected from archaeological contexts on Tenerife and Fuerteventura islands allowed us to quantify the marine C-14 reservoir effect (Delta R) around the Canary Archipelago. Coastal Fuerteventura has a positive weighted mean Delta R value of +185 +/- 30 C-14 yr, while for Tenerife a range of negative and positive values was obtained, resulting in a Delta R weighted mean value of 0 +/- 35 C-14 yr. These values are in accordance with the hydrodynamic system present off the Canary Islands characterized by a coastal upwelling regime that affects the eastern islands (Fuerteventura and Lanzarote) but not the other islands of the archipelago, namely Tenerife. Because of this oceanographic pattern, we recommend the extrapolation of these results to the remaining islands of the archipelago, i.e. the first value must be used for the eastern islands, while for the central and western islands the acceptable Delta R value is 0 +/- 35 C-14 yr