Recycling of cosmogenic nuclides after their removal from the atmosphere; special case of appreciable transport of 10Be to polar regions by aeolian dust

In this paper we discuss the general problem of recirculation of atmospheric cosmogenic isotopes after their initial removal from the atmosphere. Practically all nuclides are recycled after their removal from the atmosphere. The noble gas radio-nuclides re-circulate between the atmosphere and the hydrosphere; the fraction of time spent in these reservoirs depends on their solubility and half-lives. Radiocarbon atoms spend most of their life-time in the oceans before being removed to the sediments. All cosmogenic nuclides which are removed from the atmosphere by wet precipitations spend most of their life-time in the hydrosphere or in sediments. A special exception arises in the case of nuclides such as 10Be and 26Al, which are particle-active and adhere to aerosols and top soils in the lithosphere. Strong winds dislodge surface particles and transport the smaller particles to great distances.We discuss the special case of the transport of particle reactive 10Be via aeolian dust, which can result in appreciable 10Be fluxes in polar regions in cold climates, vis-à-vis its direct deposition from the atmosphere. We compare estimated concentrations of dust transported 10Be with the measured total10Be concentrations in Antarctica in the Vostok and Taylor Dome ice cores, and atmospheric10Be concentrations in Greenland in the GISP and GRIP ice cores. During certain epochs, high aeolian dust concentrations contribute significantly to 10Be fluxes in Greenland, comparable to or greater than atmospheric 10Be fluxes. In the Antarctica, however, even during epochs of high dust fluxes, the aeolian 10Be contributions are < 10% of the atmospheric 10Be fluxes. These results imply that great care should be taken in analyzing 10Be concentrations in Greenland especially!