Options
Oberlin, Christine
Loading...
2 results
Now showing 1 - 2 of 2
- PublicationRestrictedUse of the Radiocarbon Activity Deficit in Vegetation as a Sensor of CO2 Soil Degassing: Example from La Solfatara (Naples, Southern Italy)Soil CO2 flux measurement is a key method that can be used to monitor the hazards in an active volcanic area. In order to determine accurately the variations of the CO2 soil emission we propose an approach based on the radiocarbon (14C) deficiency recorded in the plants grown in and around the Solfatara (Naples, Italy). We twice sampled selected poaceae plants in 17 defined sites around the Solfatara volcano. 14C measurements by liquid scintillation counting (LSC) were achieved on the grass samples. The 14C deficiency determined in the sampled plants, compared to the atmosphere 14C activity, ranged from 6.6 to 51.6%. We then compared the proportion of magmatic CO2 inferred to the instantaneous measurements of CO2 fluxes from soil performed by the accumulation chamber CO2 degassing measurement at the moment of the sampling at each site. The results show a clear correlation (r=0.88) between soil CO2 fluxes and 14C activity. The determination of the plants 14C deficiency provides an estimate of the CO2 rate within a few square meters, integrating CO2 soil degassing variations and meteorological incidences over a few months. It can therefore become an efficient bio-sensor and can be used as a proxy to cartography of the soil CO2 and to determine its variations through time
68 2 - PublicationRestrictedRapid lea-level movements and noneruptive crustal deformations in the Phlegrean Fields caldera, Italy(2006)
; ; ; ; ; ;Morhange, C.; CEREGE, CJB, Universite´ Aix-Marseille, 29 avenue Robert Schuman, F-13621 Aix-en-Provence, France ;Marriner, N.; CEREGE, CJB, Universite´ Aix-Marseille, 29 avenue Robert Schuman, F-13621 Aix-en-Provence, France ;Laborel, J.; Universite´ de la Me´diterrane´e, Faculte´ des Sciences de Luminy, F-13288 Marseille, France ;Todesco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Oberlin, C.; Centre de Datation par le Radiocarbone, Universite´ Lyon 1, F-69622 Villeurbanne, France; ; ; ; The importance of Pozzuoli’s archaeological ruins in linking sea-level change and Earth deformation with volcanic activity has been recognized since the nineteenth century. The pillars of the Roman market were used as a paleotide gauge by pioneer geologists such as Lyell. For the first time, we have radiocarbon dated biological indicators on these remains, showing three 7 m relative sea-level highstands during the fifth century A.D., the early Middle Ages, and before the 1538 eruption of Monte Nuovo. These repeated uplift and subsidence cycles, not always followed by volcanic activity, have important implications for the evaluation of volcanic hazard.248 32