Nitrogen, noble gases (He, Ne, Ar) and some of their isotopes (4He, 20Ne, 22Ne, 36Ar, 38Ar, 40Ar) were measured in the fumaroles at the crater of Vulcano (Italy), during a special survey from June to September 1988. Since 1979 the survey has been carried out on two fumaroles (F1 and F5) but it was extended to other medium-temperature fumaroles (F5AT, FO, FA) during the summer of 1988. In 1987 a decrease was recorded in the 40Ar/36Ar, N2/Ar, He/Ne and He/Ar ratios; these are still decreasing towards values close to atmospheric in all the sampled fumaroles. The excess of the radiogenic component (4He, 40Ar), that was clearly detected in the period 1982-1986, is thus masked by the increase of the atmospheric species (in particular Ar). The Ne/Ar and N2/Ar ratios suggest that an inflow of a non-degassed air saturated water in the volcanic system is the likely explanation for the observed variation.
Light noble gases and nitrogen in the crater fluids at Vulcano (Italy): special survey from June to September 1988
G Magro;M Pennisi
1991-01-01
Abstract
Nitrogen, noble gases (He, Ne, Ar) and some of their isotopes (4He, 20Ne, 22Ne, 36Ar, 38Ar, 40Ar) were measured in the fumaroles at the crater of Vulcano (Italy), during a special survey from June to September 1988. Since 1979 the survey has been carried out on two fumaroles (F1 and F5) but it was extended to other medium-temperature fumaroles (F5AT, FO, FA) during the summer of 1988. In 1987 a decrease was recorded in the 40Ar/36Ar, N2/Ar, He/Ne and He/Ar ratios; these are still decreasing towards values close to atmospheric in all the sampled fumaroles. The excess of the radiogenic component (4He, 40Ar), that was clearly detected in the period 1982-1986, is thus masked by the increase of the atmospheric species (in particular Ar). The Ne/Ar and N2/Ar ratios suggest that an inflow of a non-degassed air saturated water in the volcanic system is the likely explanation for the observed variation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.