GNGTS 2013 - Atti del 32° Convegno Nazionale

succession, dissected by normal faults. During Cenozoic orogeny, the gulf area represented the frontal part of the SW-ward advancing Dinaric thrust system, and was initially buried by foredeep flysch sediments of Eocene age, then affected by thrusts in the final stage of Dinaric deformation. In Late Cenozoic continuing convergence of the Adriatic microplate towards Eurasia produced transpressional reactivation of the faults, which might be continuing into the present time, as seismic profiles have revealed that tectonic deformation is affecting the Quaternary marine and continental sediments. We found geophysical evidence of fluid migrations through the sedimentary units, that are spatially associated with major neotectonic fault zones. Neotectonic activity provides permeable fracture systems along which the fluids migrate. The fluids may come both from the low-enthalphy carbonate reservoir, as well as from the terrigenous sedimentary sequence bearing biogenic gas. Acknowledgements. The authors acknowledge the crew and the scientific party of the R/V OGS Explora and of the Harpha Sea support vessel, for collecting the geophysical data. References Busetti M., Volpi V., Barison E., Giustiniani M., Marchi M., Ramella R., Wardell N. and Zanolla C., 2010a: Meso-Cenozoic seismic stratigraphy and the tectonic setting of the Gulf of Trieste (northern Adriatic) . GeoActa, SP 3 , 1-14. Busetti M., Volpi V., Nicolich R., Barison E, R. Romeo, L. Baradello, Brancatelli G., Giustiniani M., Marchi M., Zanolla C., Wardell N., D. Nieto, and Ramella R.; 2010b: Dinaric tectonic features in the Gulf of Trieste (Northern Adriatic) . Boll. Geof. Teor. Appl., 51 (2-3), 117-128. Calore C, Della Vedova B, Grassi S, Marson I, Nicolich R, Squarci P (1995) A hydrotermal system along the coastal area of Friuli–Venezia Giulia Region (NE Italy) . In: Proceedings of the World Geothermal Congress, Florence, 2, 1269–1274. Cimolino A., Della Vedova B., Nicolich R., Barison E. and Brancatelli G.; 2010: New Evidence of the outer Dinaric deformation front in the Grado area (NE-Italy). Rend. Fis. Acc. Lincei 21-Suppl. 1: S167-S179. DOI 10.1007/s12210- 010-0096-y. Della Vedova B., Castelli E., Cimolino A., Vecellio C., Nicolich R. and Barison E.; 2008: La valutazione e lo sfruttamento delle acque geotermiche per il riscaldamento degli edifici pubblici . Rassegna Tecnica del Friuli Venezia Giulia, 6 /2008, 16-19. Doro, 1939 . Analisi chimica e chimico-fisica delle acque delle Terme di Monfalcone . Annali di Chimica Applicata, XXIX. Gordini E., Marocco R., Tunis G., and Ramella R., 2004. I depositi cementati del Golfo diTrieste (Adriatico Settentrionale): Distribuzione areale, caratteri geomorfologici e indagini acustiche ad alta risoluzione . Il Quaternario, 17 (2/2), 555- 563. Gordini E., Ciriaco S., Borme D., Cibic T., Falace A., Faresi L., Marocco r., Odorico R., Poloniato D., and Kaleb S., 2010: Trezze o “Grebeni”: biotopi e geotopi dell’Alto Adriatico . OGS, 246 pp. Fantoni R., Catellani D., Merlini S., Rogledi S., and Venturini S., 2002: La registrazione degli eventi deformativi cenozoici nell’avampaese veneto-friulano. Mem. Soc. Geol. Italiana, 57 , 301-313. Placer L.; 2008: Principles of the tectonic subdivision of Slovenia . Geologija 51 (2), 205-217. Placer L., Vrabec M., and Celarc B., 2010. The base for understanding of the NW Dinarides and Istria Peninsula Tectonics. Geologija 53/1, 55-86, doi:10.5474/geologija.2010.005 Poli E., and Zanferrari A., 2008: Inquadramento geologico e lineamenti strutturali . In: Note Illustrative della Carta Geologica d’Italia alla scala1:50.000, Foglio 066 Udine. 23-34. Weber, J., Vrabec, M., Pavlovčič-Prešeren, P., Dixon, T., Jiang, Y., Stopar, B., 2010: GPS-derived motion of the Adriatic microplate from Istria Peninsula and Po Plain sites, and geodynamic implications . Tectonophysics 483, 214-222, doi:10.1016/j.tecto.2009.09.001 Žumer J., 2004: Odkritje podmorskih termalnih izvirov . Geografski Obzornik, 51 (2), 11-17. 34 GNGTS 2013 S essione 3.1