Terrestrial manganese-53 — A new monitor of Earth surface processes

We report the first systematic study of the terrestrial cosmogenic radionuclide manganese-53 (T1/2 = 3.7 Ma) measured in thirteen samples from nine dolerite surfaces in the Dry Valleys, Antarctica. The terrestrial manganese-53 concentrations correlate well with cosmic-ray-produced helium-3 and neon-21 concentrations in the same samples, implying that the manganese-53 is produced continuously in situ and retained quantitatively over millions of years. The terrestrial manganese-53 production rate determination normalized to iron (the only important target element) and to high-latitude and sealevel yields a value of P53 = 103 ± 11 atoms yr− 1 (g Fe)− 1. This is consistent with the theoretical value of 120 ± 18 atoms yr− 1 (g Fe)− 1 obtained from modeling calculations. Our results show that the manganese-53 concentrations in bulk terrestrial rocks can be used to monitor Earth surface processes on time-scales exceeding 10 My.