Geology 38, 19–22 (2010)

The composition of dust blowing into the Mediterranean Sea from North Africa varies according to season and, new work suggests, is also influenced by broader oceanic and atmospheric cycles. As a result, dust may help researchers to reconstruct past regional climates.

Tom Jilbert of Utrecht University in the Netherlands and his colleagues used a high-resolution spectroscopy system to analyse the composition of a sediment core from off the coast of southern Greece.

Variable levels of aluminium, silicon and other elements indicate two dust sources. The team proposes that periods of low air pressure during Mediterranean summers bring about westerly winds, which carry in dust from Tunisia and Algeria. Periods of high pressure block dust from that area, leading to a relative increase in dust from the south.

The group also found that dust deposition rates correlated with regional sea surface temperatures, which serve as a surrogate for broader climate and ocean-cycle trends.