Anomalous Radiocarbon Ages Found in Campanian Ignimbrite Deposit of the Mediterranean Deep-Sea Core CT85-5

A detailed radiocarbon chronology has been established for the deep-sea core CT85-5 from the Tyrrhenian Sea. This chronology, which is based on the analysis of foraminifera shells, shows a set of reversed C-14 ages for sediments deposited during the eruption of the Campanian Ignimbrite (similar to 40 ka cal BP). The anomalous young C-14 ages coincide with elevated concentrations of Be-10 measured in the same core. Although reversals in C-14 ages have been previously found in other records at 40 ka cal BP, such extreme changes have not been observed elsewhere. The enhancement in C-14 concentration in CT85-5 sediments associated with the Campanian Ignimbrite is equivalent to an apparent age similar to 15 ka younger than the age for the sediments deposited shortly before the eruption. Here, we present consistent results of repeated measurements showing no analytical problems that can explain the observed rapid changes in C-14 of this particular record.