Lead (Pb) in old Antarctic ice: Some from dust, some from other sources

Recently published data on amounts and isotopic compositions of lead (Pb) and on amounts of mineral dust in pre-industrial Antarctic ice can be further interpreted by means of simple calculations. These show that two distinct types of Pb were provided by the atmosphere to the continent in varying proportions during Pleistocene and Holocene time. One type of Pb is that contained in the mineral lattices of dust. It has non-radiogenic isotopic proportions. The other type of Pb is not associated with dust minerals, is more radiogenic, and is consistent with an origin in emissions from ocean island volcanoes worldwide, or from some Antarctic volcanoes.