“…This behaviour can be explained by the synoptic transport of air masses in the region (Murphey and Hogan, 1992) as well as by human activities at scientific stations in KGI (Evangelista, 1998) that maintain operation mostly during the austral summer. More recently, Dias da Cunha et al (2004) employing a plasma desorption mass spectrometry (PDMS) technique in two samples of shallow snow cores (5 m each) from a site near Lange Glacier detected insoluble carbon structures that can be attributed to an anthropogenic source, such as VC + n and CF + n ; or a biogenic origin, such as CH 3 NH + ; CH 2 CN + ; NH 4 CN + ; C n H + m as C 2 H + , C 2 H + 2 , C 2 H + 3 , C 2 H + 5 , C 3 H + 3 , C 3 H + 5 , C 5 H + , C 5 H + 8 , C 6 H + 5 , C 6 H + 10 and C 7 H + 3 ; and C n H m O + as CH 3 O + , C 3 H 7 O + and C 4 H 5 O + . Carbon structures with Si enrichment were also found as (CH 3 ) 2 SiH + and (CH 3 ) 5 Si 2 O + .…”