GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 1.2 231 compare them with onshore units by integration of interpreted structural framework. This was achieved by synthetic seismogram generation, while some seismic attributes were used to improve fault detection and better recognition of some deep reflectors, particularly the Top Triassic clastites/base Carbonates. As result, interpreted seismic lines provide information about mapped seismic facies distribution. Whole sequence can be generally separated into some main sequences that are not always seismically well defined. From the bottom to the top, the first is the Permo-Triassic clastic sequence, characterized by deep low frequency reflectors below the Base Carbonates horizon. It is overlain by a thick sequence of Jurassic- Paleogene carbonates, with a changeable, mainly opaque seismic facies. This sequence is often tectonically and erosional disturbed, due to several episodes of intense erosion followed by karstification. Above this, the Eocene clastic sequence is often at the limit of the seismic resolution, with the Flysch unit only locally present, characterized by medium/high amplitude reflectors gradually disappearing toward west. The upper sequence is represented by Neogene and Quaternary siliclastic deposits, generally showing medium/high amplitude reflectors. The Messinian age processes can be recognized inside this sequence, with alternate process of sedimentation in some parts of the area, and simultaneous erosion in other parts. Erosional processes related to Messinian age are evident as large canyons especially present on the line from Susak Island to the Istria shoreline, while a regional erosional truncation characterizes the westward deepening outermost sector. Recognition and interpretation of the seismic facies led to reconstruction of the spatial distribution of the different sedimentary units and structures with aim to correlate them with those mapped onshore. The Messinain canyons seem to be developed above the main fault zones evidenced along the seismic profiles. Accordingly, this can be the potential zone of Kvarner fault (Salopek, 1954; Juračić, 1999; Grandić et al ., 2010; Korbar, 2009; Placer et al ., 2010; Soto et al ., 2017), which is previously not well mapped. One of the most important structures recognized on the dataset is the frontal Dinarides thrust: to the western offshore area, several transpressional faults are occurring, which can be described as part of a regional flower structure system, probably reactivated also in recent times. The exact structural style, geometry and their relationship definition is in progress, due to the huge amount of data. 3D modeling tools and balanced sections are currently producing new results to better define the recent tectonics of the area. Acknowledgements. This work is part of GEOSEKVA project (IP-06-2016-1854) funded by Croatian Science Foundation (HRZZ). The whole research is conducted using academic license of Petrel software, provided by Schlumberger Company. Authors are grateful to Croatian Hydrocarbon Agency (AZU) for 2D seismic and well data usage permission as well. References Aljinović, B., Prelogović, E., Skoko, D.; 1987: Novi podaci o dubinskoj geološkoj građi i seizmotektonski aktivnim zonama u Jugoslaviji ( New data on deep geological structure and seismotectonic active zone in region of Yugoslavia ). Geološki Vjesnik, 40, 255-263. Busetti, M., Volpi, V., Barison, E., Giustiniani, M., Marchi, M., Ramella, R., Wardell, N., Zanolla, C.; 2010: Meso- Cenozoic seismic stratigraphy and the tectonic setting of the Gulf of Trieste ( northern Adriatic ). Geology of the Adriatic area, GeoActa, Special Publication, 3, 1-14. Cazzini, F., Zotto, O., Fantoni, R., Ghielmi, M., Ronchi, P., Scotti P.; 2015: Oil and gas in the Adriatic foreland, Italy . Journal of Petroleum Geology, 38 (3), 255-279. DOI 10.1111/jpg.12610. Del Ben, A.; 2002: Interpretation of CROP M-16 Seismic Section in the the Central Adriatic Sea . Mem. Soc. Geol. It, 57, 327-333. Juračić, M., Benac, Č., Crmarić, R.; 1999: Seabed and Surface Sediment Map of the Kvarner Region, Adriatic Sea, Croatia (Lithological Map, 1:500,000) . Geologia Croatica, 52/2, 131-140, DOI 10.4154/GC.1999.11. Finetti, I.; 2005: CROP PROJECT: Deep Seismic Exploration of the Central Mediterranean and Italy . Elsevier, Volume 1, 794. GKSFRJ; 1970: Geološka karta SFR Jugoslavije ( Geological Map of the SFR Yugoslavia ) scale 1:500.000 . Savezni geološki Zavod, Beograd (Federal geological Institute, Belgrade), 1 sheet.