Radiocarbon reservoir corrections on the Brazilian coast from pre-bomb marine shells

• Pre-bomb shells from a museum collection were radiocarbon dated.
• We obtained the first radiocarbon reservoir corrections for some regions on the Brazilian coast.
• The values range from 17 ± 56 14C yr in São Jose do Norte, Rio Grande do Sul to 96 ± 48 14C yr in Cabo Frio, Rio de Janeiro.

Despite the great extent of the Brazilian coast, there are very few studies on the marine radiocarbon reservoir correction local offset (ΔR) for this region.In the present study, we used marine shells from the malacological collection of the National Museum of Brazil to obtain values of ΔR for different locations on the Brazilian coast. According to the museum records, the mollusks were collected alive from the coasts of Rio de Janeiro, Rio Grande do Sul, São Paulo and Bahia, prior to the 14C bomb-peak. The exact year of collection for each shell is known.The samples were chemically prepared and measured at the Radiocarbon Laboratory of the Universidade Federal Fluminense (LAC-UFF) in Brazil. The conventional ages were calibrated using the Marine13 curve and the ΔR values were calculated using the OxCal software. The values range from 17 ± 56 14C yr in São José do Norte, Rio Grande do Sul to 96 ± 48 14C yr in Cabo Frio, Rio de Janeiro.