Tracing dust sources and transport patterns using Sr, Nd and Pb isotopes

Continental dust transported through the atmosphere can be a tracer of atmospheric circulation and transport, as well as being a source of information about climate in the dust's source area. This information about the provenance of dust transported from desert areas and deposited elsewhere on the oceans and continents can be evaluated using several observational techniques. Satellite imagery has been used to this end in recent decades, and air-mass back trajectories have been calculated to trace dust deposits back to their source area. Another method consists of analysis of the concentration and composition of certain tracers in the dust itself, and comparing them to soils and sediments from possible source areas. This method has the advantage of being useable for paleo-atmospheric circulation and paleo-dust transport studies, whereas satellite imagery and air-mass back trajectories are restricted to relatively recent times. We review here different kinds of isotopic tracers that have been used to trace dust provenance, but special attention is focused on the use of Sr, Nd and Pb isotopes. We evaluate their use in studies of both spatially as well as temporally varying continental dust source and transport.