δ13C and 14C activity of groundwater DOC and DIC in the volcanically active and arid Loa Basin of northern Chile

•14C and δ13C in DIC and DOC have been measured in groundwater in the Atacama Desert.•DIC is affected by volcanic CO2 inputs followed by degassing and carbonate precipitation.•14CDOC-based C residence times are consistent with late Holocene paleoclimate records.•Carbon transit times across the Calama Basin based on 14CDOC and 14CDIC agree.