Chemical composition of fresh snow from Glaciar Marinelli, Tierra del Fuego, Chile

Abstract

A fresh-snow sampling campaign was conducted during the late austral summer of 2006 in the accumulation zone of Glaciar Marinelli, located in the Cordillera Darwin, Tierra del Fuego, Chile. Snow samples were analyzed for stable isotopes (δ18O), major soluble ions (Na+, K+, Ca2+, Mg2+, Cl-, NO 3-, SO42-, MS-) and major and trace elements (Na, Mg, AI, Fe, Ca, Sr, Cd, Cs, Ba, La, Ce, Pr, Dy, Ho, Er, Bi, U, As, Ti, V, Cr, Mn). The dominance of marine chemistry resembles that in studies from Patagonian glaciers. Snow chemistry was dominantly loaded by marine species (Cl-, Na+ and ssSO42-), while contributions of crustal species (e.g. Al and Fe) were very low. Empirical orthogonal function analysis suggests two possible dust sources, one represented by Al and Fe and the other by La, Ce and Pr. Enrichment-factor calculations suggest the majority of elements are within average upper-crustal ratios, but major enrichments of Bi and Cd (hundreds of times) suggest possible anthropogenic sources. Linear correlation of δ18O and barometric pressure (r = 0.60, ρ< 0.007) suggests a potential amount effect relationship between depleted δ18 ratios and stronger storm conditions (e.g. greater precipitation). The snow-chemistry records from Glaciar Marinelli are the first measured in Tierra del Fuego, the southernmost glaciated region outside Antarctica.