RESUMEN
The 53Mn flux onto Earth is a quantity relevant for different extraterrestrial and astrophysical questions. It is a proxy for related fluxes, such as supernova-produced material or interplanetary dust particles. In this work, we performed a first attempt to assess the 53Mn flux by measuring the 53Mn/10Be isotopic ratio in a 1400â¯L sample of molten Antarctic snow by AMS (Accelerator Mass Spectrometry). Using the 10Be production rate in the atmosphere, an upper limit of 5.5â¯×â¯103 atoms cm-2 yr-1 was estimated for the deposition of extraterrestrial 53Mn. This result is compatible with one of the two discrepant values existing in the literature.
RESUMEN
Measurements of total iodine (I) and iodine-129 ((129)I) concentrations in rivers and lakes of Argentina are presented. Their latitudinal distribution can be explained by taking into account their main sources (oceanic emissions and biomass burning for I, and atmospheric nuclear tests for (129)I), transport mechanisms, and fallout patterns. From the measured (129)I concentrations in the studied lakes, deposition fluences for their catchment areas were estimated. These results agree with a model of the global deposition pattern due to the (129)I released by atmospheric nuclear weapon tests and with other fluences reported for the southern hemisphere. In addition, the first measurements of (129)I in shallow seawater from the South Atlantic Ocean are presented and discussed.