Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | GROWING PROCESSES OF AN INLAND ANTARCTIC ICE WEDGE, MESA RANGE, NORTHERN VICTORIA LAND |
| Abstract | During the XVI Italian Antarctic Expedition (2000-2001) the geomorphologic survey of permafrost-related polygons has been carried out in the northern sector of Mesa Range - Pain Mesa - located in the upper part of Rennick Glacier. An ice wedge was found in a volcanic regolith at an elevation of about 2200 m a.s.l.. This altitude is below the trimline that in this sector of Mesa Range is at 2380 m a.s.l.. Samples of ice were taken using a 14 mm internal diameter ice screw that was inserted into the ice wedge in vertical sequences. A co-isotopic study was performed, measuring both oxygen (?18O) and hydrogen (?D) isotope compositions. Tritium activity measurements were carried out on the same samples as well as chemical determinations of both major cations and anions. The ?18O and ?D obtained showed a strong divergence from the expected snowfalls occurring at this elevation, with extremely negative d excess values. Melting-refreezing and/or sublimation processes were taken into account to define the origin of the ice forming the wedge. The tritium data obtained suggest that the growth process of the ice wedge might be active still today. High values of non-sea salt sulphate concentrations, obtained for all samples, showed a strong contribution from a terrestrial source for sulphate which is probably associated with calcium. |
| Source | Annals of glaciology 39 (2), pp. 379–385 |
| Journal | Annals of glaciology |
| Editor | International Glaciological Society., [Cambridge], Regno Unito |
| Year | 2004 |
| Type | Articolo in rivista |
| DOI | 10.3189/172756404781814195 |
| Authors | RAFFI R., STENNI B., FLORA O., POLESELLO S., CAMUSSO M. |
| Text | 42229 2004 10.3189/172756404781814195 ISI Web of Science WOS 000232368400057 GROWING PROCESSES OF AN INLAND ANTARCTIC ICE WEDGE, MESA RANGE, NORTHERN VICTORIA LAND RAFFI R., STENNI B., FLORA O., POLESELLO S., CAMUSSO M. R. RAFFI 1 , B. STENNI 2, O. FLORA 2, S. POLESELLO 3 M. CAMUSSO 3 1Dip. Scienze della Terra, Universita degli Studi La Sapienza , P.le Aldo Moro 5, 00185 Roma 2Dip. Scienze Geologiche, Ambientali e Marine, Universita di Trieste, Via E. Weiss 2, 34127 Trieste 3CNR Istituto di Ricerca sulle Acque, via Mornera 25, 20047 Brugherio MI During the XVI Italian Antarctic Expedition 2000 2001 the geomorphologic survey of permafrost related polygons has been carried out in the northern sector of Mesa Range Pain Mesa located in the upper part of Rennick Glacier. An ice wedge was found in a volcanic regolith at an elevation of about 2200 m a.s.l.. This altitude is below the trimline that in this sector of Mesa Range is at 2380 m a.s.l.. Samples of ice were taken using a 14 mm internal diameter ice screw that was inserted into the ice wedge in vertical sequences. A co isotopic study was performed, measuring both oxygen 18O and hydrogen D isotope compositions. Tritium activity measurements were carried out on the same samples as well as chemical determinations of both major cations and anions. The 18O and D obtained showed a strong divergence from the expected snowfalls occurring at this elevation, with extremely negative d excess values. Melting refreezing and/or sublimation processes were taken into account to define the origin of the ice forming the wedge. The tritium data obtained suggest that the growth process of the ice wedge might be active still today. High values of non sea salt sulphate concentrations, obtained for all samples, showed a strong contribution from a terrestrial source for sulphate which is probably associated with calcium. 39 ARTICOLO AnnalsGlaciology.pdf Articolo in rivista International Glaciological Society. 0260 3055 Annals of glaciology Annals of glaciology Ann. glaciol. stefano.polesello POLESELLO STEFANO marina.camusso CAMUSSO MARINA |