GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.1 567 Kissling E., Schmid S.M., Lippitsch R., Ansorge J. and Fügenschuh B.; 2006: Lithosphere structure and tectonic evolution of the Alpine arc: new evidence from high-resolution teleseismic tomography . Geological Society of London Memoirs, 32 , 129-145, doi:10.1144/GSL.MEM.2006.032.01.08. Lippitsch R., Kissling E. andAnsorge J.; 2003: Upper mantle structure beneath the Alpine orogen from high-resolution teleseismic tomography . J. Geophys. Res., 108 (B8), 2376, doi:10.1029/2002JB002016. Mitterbauer U., Behm M., Brückl E., Lippitsch R., Guterch A., Keller G.R., Koslovskaya E., Rumpfhuber E.-M. and Sumanovac F.; 2011: Shape and origin of the East-Alp slab constrained by the ALPASS teleseismic model . Tectonophysics, 510 (1-2), 195-206, doi:10.1016/j.tecto.2011.07.001. Mountain Building Processes in Four Dimensions (MB-4D); 2017: http://www.spp-mountainbuilding.de/ Brisbourne A., Clinton J., Hetényi G., Pesaresi D., Aubert C., Bokelmann G., Csicsay K., Gráczer Z., Haberland C., Hawthorn D., Herak M., Kristeková M., Lane V., Lenhardt W., Margheriti L., Paul A., Péquegnat C., Plomerová J., Ritter J., Sleeman R., Vecsey L., Vergne J., Villaseñor A., Wassermann J., Wilde-Piórko M. and Živčić M.; (2013): Technical strategy for the mobile seismological components of AlpArray . http://www.alparray.ethz.ch/ export/sites/alparray/.galleries/dwn-experiments/AlpArray_TechnicalStrategy.pdf TRANSALP Working Group; 2002: First deep seismic reflection images of the Eastern Alps reveal giant crustal wedges and trans crustal ramps . Geophys. Res. Lett., 29 (10), 92.1-92.4, doi:10.1029/2002GL014911. EVIDENCE OF BOTTOM CURRENT-CONTROLLED QUATERNARY SEDIMENTATION ON THE EASTERN SICILY MARGIN (IONIAN SEA) M. Rebesco 1 , A. Camerlenghi 1 , V. Munari 1 , R. Mosetti 1 , A. Micallef 2 , L. Facchin 1 , D. Accettella 1 1 OGS, Sgonico (TS), Italy 2 Department of Geosciences, University of Malta, Msida, Malta A sedimentary wave field has been observed at the base of the Malta-Sicily Escarpment, in the western Ionian Sea during the “CUMECS-3” project on the base of multichannel seismic reflection data, sub-bottom (CHIRP) acustic profiles and Multibeam echo–sounder data. The wave field consists of asymmetric sediment waves at the depth of about 2400-2600 mbsf. They are interpreted as being deep-water contourite deposits produced by bottom currents flowing close to the continental slope. This deposits seems to have started to grow already after the Messinian Salinity Crisis, but a more regular development of the sediment waves with consitent northwest migration of their crests takes place above a widespread unconformity surface that has been roughly dated at 650 ka. The sedimentary process are hence likely to be controlled by the same forcings since the Mid Pleistocene Transition (MPT), which led to a rise in the velocity of the bottom currents in the Mediterranean Sea. The analysis of the modern oceanographic data (Manca et al. , 2002; Sparnocchia et al. , 2011) support a flow direction towards SE, almost perpendicular with respect to thewave crests. The comparison with contourite deposits in the Tyrrhenian Sea (Miramontes et al. , 2016), where a similar unconfromity at the base of the contourite deposits is also identified and assumed to correspond to the MPT, suggests a paleoclimatic control on the widspread onset of bottom-current controlled sedimentation in the Mediterranean Sea. The uderstanding of the sedimentary processes that take place at the base of the continental slope is of great significance with respect to palaeoclimatology and palaeoceanography, slope stability and hydrocarbon exploration. The action of contour currents has in fact an impact on the petroleum systems in many aspects, including reservoir geometry and quality, and the distribution of sealing rocks. Changes of the seafloor topography by erosion or deposition induced by bottom currents can result in a re-adjustment of the sediment accommodation space and the creation of sub-basins, which act as sediment traps or gateways for sediment transfer. Coarse-grained contourites deposited by robust flows may represent hydrocarbon reservoirs, whereas fine-grained contourites accumulated by weak bottom currents may provide sealing (and source) rocks.