6533b85efe1ef96bd12bfb21

RESEARCH PRODUCT

Degassing of trace volatile metals during the 2001 eruption of Etna

subject

description

This paper provides new data on sulfur, halogens, and minor and trace metal contents in airborne particulate matter from the Mt. Etna volcanic plume. Aerosol samples were collected by conventional filtration techniques before and during the summer 2001 eruption, in order to investigate relations between plume chemistry and volcano dynamics. Data analysis reveals that abundances of trace metals in the plume result from mixing of erosive and volatile components. The former is responsible for the contents of rare earth elements (REE), Ca, Ba, Sr, Ti, Sc, Y, Hf and Th; the latter contributes significantly to the abundance of Cs, Rb, Na and K, probably transported in the plume as metal halides, and Cd, Pb, Zn, Ge, Te, Mo, Re, Se, Sb, Sn, In, Bi, Tl, Cu and Au, associated with sulfur in plume particles. Enrichment factors show that plume particulate matter from the Monti Carcarazzi vent, which opened on the southern flank of the volcano in July 2001, is typically depleted in volatile trace elements with respect to the output from the summit crater, suggesting the secondary nature of the outpouring lavas. The decreasing trend observed throughout the eruption in the enrichment factors of most trace metals probably indicates a small-volume batch of magma with limited feed from depth.