Chemical characterisation of a volcanic event (about AD 1500) at Styx Glacier plateau, northern Victoria Land, Antarctica

This is the authors' abstract. We don't add key points for this paper.

A dark layer (∼1 cm thick, 93.41 m deep) was identified in an ice core (116 m deep, covering the period -1350-1995) drilled at Styx Glacier plateau, northern Victoria Land, Antarctica. The ice-core section was dated around AD 1500 ± 20 by a firn-densification model. A chemical characterisation was performed on ten subsamples (resolution 3 cm) located around the dark layer by ion chromatography. The concentration/depth profiles of anions (Cl-, Br-, NC3-, H 2 PO 4 -, SO 4 2 -), cations (Na + , NH 4 + , K + , Mg* + , Ga 2 ^) and some organic anions (acetate, formate, propionate and methanesulphonate (MSA)) indicate very high concentration peaks for all the components. However, non-sea-salt sulphate (nssSo/-) and F- show the greatest increase with respect to background values (370 and 860 times, respectively). A crustal contribution is attributed to Ga 2+ and MSA. The profiles of gas-phase emitted substances (HF, HBr, HNO s and carboxylic acid) suggest gas emission just before the volcanic eruption. Chloride depletion is evident in the dark layer with respect to Na + /Cl- sea-water ratio. At present, it is not possible to attribute an unambiguous source to the volcanic event, but several pieces of evidence lead us to believe that this may be a time-limited local event.