NEW MARINE Delta R VALUES FOR THE SOUTH PACIFIC SUBTROPICAL GYRE REGION

This paper presents 31 new Delta R results of known-age, pre-AD 1950 shells from the South Pacific subtropical gyre region, spanning from the Tuamotu Archipelago in the east to New Caledonia in the west. This doubles the number of available Delta R values for the Oceania region, These values indicate that the regional offset (Delta R) from the modeled radiocarbon marine age has remained relatively constant over the last 100 yr prior to 1950. Variation front the norm can be attributed to various influences including localized upwelling around islands, the presence of a hardwater effect, direct ingestion of old carbon by the live shellfish. or enhanced exchange with atmospheric CO2 as a consequence of photosynthetic activity or increased aeration.