Atmospheric dust contribution to the budget of U-series nuclides in soils from the Mount Cameroon volcano

Abstract : The atmospheric dust contribution to U-series nuclides in soils is evaluated by analyzing two soil and paleo-soil (<10 ka) profiles from the Mount Cameroon volcano where Sr-Nd-Pb fingerprints are clearly affected by Saharan dust accretion. The comparison of measured U-series disequilibria between bulk soils and associated parent lavas suggests that dust inputs can contribute up to 25% of the U and Th budget in soils whereas chemical weathering affects a maximum of 7% of the U budget. The uniform U-Th isotopic composition of the Saharan dust end-member inferred from the soils and the paleo-soils suggests a relative stability of the Saharan dust isotopic composition during the last 10 ka.