http://hdl.handle.net/2122/133 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4005 Title: Isotopic composition of single rain events in the central Mediterranean <br/> <br/>Authors: Liotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Bellissimo, S.; Dipartimento di Chimica e Fisica della Terra, Universita` degli Studi di Palermo; Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Valenza, M.; Dipartimento di Chimica e Fisica della Terra, Universita` degli Studi di Palermo <br/> <br/>Abstract: The ratios of stable isotopes of single rain events were investigated during the period October 2005 to September 2006 in the central Mediterranean. Clear seasonal trends were identified in both oxygen isotope ratios and the deuterium-excess parameter, and these were ascribed to the dominant circulation systems during both cold and hot intraannual periods. Rain events were classified on the basis of the origin of rain-bearing systems. Air masses coming from the south usually give rise to rainwater with a low deuterium excess. Air masses coming from the north and the northeast are often dry and cold, and are associated with high evaporation from the Mediterranean Sea that occurs under isotopic nonequilibrium conditions. Kinetic fractionation enhances lighter isotopomers in the vapor phase, increasing the deuterium excess. During cold periods large vapor fluxes from the Mediterranean Sea, as estimated by the ECMWF (European Centre for Medium-Range Weather Forecasts), usually precede rain events with a high deuterium excess. However, the isotope signatures of the Mediterranean moisture contribution may be masked by the original isotope content of the circulating air masses and/or by secondary evaporation effects. http://hdl.handle.net/2122/3847 Title: Sedimentation and aspects of glacial dynamics from physical properties, mineralogy and magnetic properties at ODP Sites 1166 and 1167, Prydz Bay, Antarctica <br/> <br/>Authors: Forsberg, C. F.; Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, N-0806 Oslo, Norway; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Grützner, J.; University of Bremen,; Venuti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Solheim, A.; Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, N-0806 Oslo, Norway <br/> <br/>Abstract: Trough mouth fans are formed by aggradation of glacial debris flows from sediment deposited by fast flowing ice streams extending to the shelf edge. We here present investigations at two sites, ODP Site 1166 on the shelf and ODP Site 1167 drilled on the Prydz Channel Fan in order to contribute to the understanding of Neogene ice flow patterns in Prydz Bay. The mineralogy, wt.% > 63 μm, physical and magnetic properties were analyzed. The mineralogy of Neogene strata at Site 1166 can be correlated to nearby ODP Site 742 drilled during Leg 119. Moreover an increase in the shear strength of the sediments (Leg 119 load event 3) is found both at Site 1166 and Site 742. This load event probably indicates that the oldest glacial configuration involved thicker glaciers than the later ones. The results from Site 1167 show that there has been a significant change in the provenance of the sediments during the past 2 million years. The greatest change occurred at about 1.13 Ma and implies a shift in the glacial configuration in Prydz Bay with a greater contribution of material from western parts of the drainage basin during the deposition of Unit II (> 1.13 Ma; 217–435 mbsf) at Site 1167 on the Prydz Channel Fan. http://hdl.handle.net/2122/3093 Title: A Record of Antarctic Climate and Ice Sheet History Recovered <br/> <br/>Authors: Naish, T.; Antarctic Research Centre, Victoria University of Wellington, New Zealand, and Geological and Nuclear Sciences, Lower Hutt, New Zealand; Powell, R.; Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Harwood, D.; ANDRILL Science Management Office; Kuhn, G.; Department of Marine Geophysics, Alfred Wegener Institute, Bremerhaven, Germany; Niessen, F.; Department of Marine Geophysics, Alfred Wegener Institute, Bremerhaven, Germany; Talarico, F.; Dipartimento di Scienze delle Terra,Università di Siena, Siena, Italy; Wilson, G.; Department of Geology, University of Otago, Dunedin, New Zealand <br/> <br/>Abstract: Antarctica’s late Cenozoic (the past ~15 million years) climate history is poorly known from direct evidence, owing to its remoteness, an extensive sea ice apron, and an ice sheet cover over the region for the past 34 million years. Consequently, knowledge about the role of Antarctica’s ice sheets in global sea level and climate has relied heavily upon interpretations of oxygen isotope records from deep-sea cores. Whereas these isotopic records have revolutionized our understanding of climate-ice-ocean interactions, questions still remain about the specific role of Antarctic ice sheets in global climate. Such questions can be addressed from geological records at the marine margin of the ice sheets, recovered by drilling from floating ice platforms [e.g., Davey et al., 2001; Harwood et al., 2006; Barrett, 2007]. http://hdl.handle.net/2122/2527 Title: Isotopic composition of meteoric water in Sicily <br/> <br/>Authors: Liotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia <br/> <br/>Abstract: The isotopic composition of meteoric water in Sicily (Italy,) was investigated from May 2004 until Jun 2006; a rain gauge network (50 sites) was installed and sampled monthly. During this same period most of the circulating groundwater in the investigated area was sampled from more than 560 springs and wells related to the main aquifers. The mean weighted precipitation values were used to define the weighted local meteoric water line (WLMWL) for several sectors of Sicily. The use of GIS tools, coupled with isotopic vertical gradients, allowed us to design an isotopic contour map of precipitation in Sicily. The defined meteoric compositions fitted well with most of the groundwater samples for each sector. However, in some areas fractionation processes occurring during and after rainfall, slightly modified the isotopic composition of the groundwater <br/> <br/>Description: Poster