The NW sector of the Sicily Channel: geometry and evolution of inverted structural lineaments

The 3-D trend of anticline axial planes, fault planes and surfaces has been reconstructed in the offshore area between the Egadi Islands and the Sciacca High from the interpretation of multichannel seismic reflection profiles and well data (available from the VIDEPI project database). In particular, isopach maps generated for the five seismic units of age between Cretaceous and Quaternary allowed highlighting the space-time migration of the tectonic processes. The western portion of the studied area covers the submerged prolongation of the inner sector of the Sicilian-Maghrebian chain, limited in the NW and in the SE by two tectonic lineaments running along the western and eastern margins of the Adventure Bank: the Maghrebian Thrust Front and Adventure Thrust Front, respectively (see Argnani et al., 1986). The eastern portion is characterized by transpressive zones orientated NNE-SSW identifying the Separation Belt that partly corresponds to the foreland area which contains the Gela Nappe Thrust. Age constraints indicate that contraction related to the Sicilian-Maghrebian fold and thrust belt migrated progressively towards the southeast. The emplacement of the western front is attributable to the Middle-Upper Miocene while that of the eastern front is Plio-Pleistocene. Within this tectonic framework, two tectonic basins were identified on the basis of the different trend, age and evolution. The Adventure foredeep exhibits the maximum thickness of 500 m in correspondence of the Adventure Plateau. Here, the younger Gela foredeep displays minor depth showing a thickness increase towards the Gela Nappe and the Pantelleria graben. Positive inversion structures form by the Plio-Pleistocene compressional reactivation of preexisting structures limiting the Saccense and Trapanese domains were recognized the offshore sector between Mazara and Sciacca. Moreover, a correlation between the Campobello di Mazara-Castelvetrano alignment as proposed by Barreca et al., 2013, Ferranti et al., this meeting, and the tectonic units recognized in their offshore prolongation has been recognized. Therefore, we propose that in this area contractional tectonics is still active (see also Pepe et al., this meeting), and occurs on high-angle, NW-dipping crustal ramps (Monaco et al., 1996)

The transition between the Marsili oceanic crust and the W Calabria rifted margin: rifting and drifting in the upper plate of the Ionian subduction zone

The western Calabria continental margin forms the transition between the Late Pliocene to Recent Marsili spreading center and continental Calabria. Integrating highpenetration and -resolution upper crustal seismic images with seafloor morphology, ODP well data and geological/geophysical constraints we provide a detailed reconstruction of the architecture of the distal portion of the W Calabria rifted margin and of the adjacent Marsili “oceanic” domain (Fig. 1) and develop a scheme for the Pliocene to present rifting and drifting of the upper plate of the Ionian subduction zone. Our seismic data document the presence of stretched and thinned continental crust, less than 10 Km thick into the eastern sector of the Marsili abyssal plain previously considered as floored by a three-layer oceanic crust. Thinning of the crust is associated with a numbers of 2-4 km wide tilted blocks composed of an acoustic basement and pre- and syn-rift sediments. Stretching factors between 1.1 and 1.42 (ca. 40% extension) has been obtained assuming a domino-like style of deformation. With few exceptions, the infill completely smoothes out pre-existing topography and explain the flat sea floor in the area surrounding the Marsili volcano. Extensional tectonics began in the Late (?) Pliocene – Early (?) Pleistocene times and ended at ca. 0.5 Ma resulting in the formation of ca. 70 km of “oceanic” domain with an average spreading rate between ca. 5.1 and 5.9 cm/yr. The appearance of vescicular basalts in the Marsili basin was not associated with the end of extension. The post-extensional sedimentary package has fairly constant thicknesses of ca. 350 along the entire Marsili abyssal plain. The Marsili volcano grows close to the western termination of the stretched and thinned W Calabria continental crust, in an asymmetric position with respect to the < 2 Ma Marsili Basin itself

Large deep-seated gravitational slide off Ischia volcanic island, Eastern Tyrrhenian sea (Italy)

Ischia island develops at the edge of the shelf area and represents the sub-aerial section of a larger, E-W trending volcanic ridge including others submerged or buried volcanic edifices. In the past decade the island’s offshore has been the object of extensive hydrographic and marine geophysical surveys that have shown the structural complexity of the undersea sections and have overall shown the importance of gravity failures in island’s evolution. In this paper we report a previously unreported deep-seated slump structure and associated surficial mass wasting phenomena which occur off Ischia south-western flank. Recently acquired hydrological and geophysical data lead to identify the morphological features and the internal organization of the failed sediments which spread along the continental slope. The extent of this deep-seated deformations and the deep structural levels involved lead to investigate on the influence played by volcanic processes and regional tectonics on slope failure. The Ischia southern slope was explored through a multibeam survey and a single-channel seismic survey. Acquisition was carried out from aboard the R/V Urania at depths between 400 and 1200 m. The bathymetric data were collected using a hull mounted Reson 8160 multibeam sonar. Resolution resulted in a 20x20 m implemented with 50x50 gridded size provided by a previously collected data. Seismic survey consisted of 6 seismic lines run along the slope spaced 1 km between them and 5 cross lines. The acoustic source used was a 1Kjoule high-energy power supply system with a multi-tips (400) sparker array, fired at 2s time interval. The collected data show that a wide submerged area of 350 km2, between 400 to 1200 m depths is undergoing slow-moving deformation and associated secondary mass wasting phenomena. Morphological features include trenches, counterscarps, bulging and both extensional and contractional features while internal deformations show typical landward dipping reflectors with strong evidence of synsedimentary faulting and asymmetric anticlines. Deformation processes operate at various scales generating folds with wavelength ranging from hundreds meters to kilometers. Extensional and rotational rupture surfaces sole out at various low-angle detachment planes located at depths from few hundreds meters to 1 kilometer in subsurface

Large deep-seated slump structure off Ischia volcanic island, Eastern Tyrrhenian sea (Italy)

Ischia island is located over the Campania sector of Eastern Tyrrhenian margin and represents the sub-aerial section of a larger, E-W trending volcanic ridge including others submerged or buried volcanic edifices. The island itself result from the coalescence of a multitude of small to medium scale eruptions leading to the emplacement of domes, lava flow and pyroclastic deposits and ignimbrites (VEZZOLI et al., 1988) ranging from alkali basalts to trachytes. The oldest basement dates back to 150 ky and crops out along the perimeter of the island especially to the south. Latest eruption occurred in 1302 A.D. and together with strong hydrothermal activity, ground uplift and seismic shaking indicates the presence of a still active magmatic reservoir at depth. Most recent (Holocene) magmatic activity with local volcanic eruptions has clustered in the eastern island’s sector the while central sector is dominated by the Mt. Epomeo, consisting of an ignimbritic tuff (Green tuff Auct.) uplifted of 600-700 m in the past 33ka. In the past decade the island’s offshore has been the object of extensive hydrographic and marine geophysical surveys that have shown the structural complexity of the undersea sections and have overall shown the importance of gravity failures in island’s evolution. In particular a 1.5-3 km3 debris avalanche due to a subaerial and/or submarine flank collapse was emplaced along the steep and unbuttressed island’s flank during pre-historical or even historical times (CHIOCCI & DE ALTERIIS, 2006; de Alteriis et al., 2010) whereas three other similar deposits of comparable volumes were found over the continental shelf to the west and to the north (VIOLANTE et al, 2004; DE ALTERIIS & VIOLANTE, 2009). Here we report a previously unrecognized deep-seated slump structure and associated surficial mass wasting phenomena which occur off Ischia south-western flank. Recently acquired hydrological and geophysical data lead to identify the morphological features and the internal organization of the failed sediments which spread along the continental slope. The extent of this deep-seated deformations and the deep structural levels involved lead to investigate on the influence played by volcanic processes on slope failure. DATA AND METHODS Our dataset was acquired during the geophysical cruise PECOS 2010 carried out on R/V Urania (Consiglio Nazionale delle Ricerche, CNR, Italy) between December 22th 2010 and January 2nd 2011 in the frame of a project leaded by Istituto per l’Ambiente Marino Costiero, (IAMC-CNR), Naples-Italy with the collaboration of Dipartimento di Scienze della Terra e del Mare (Palermo University), Palermo-Italy regarding coastal and offshore slope instability in the Bay of Napoli. The Ischia southern slope was explored through a multibeam survey and a single-channel seismic survey. Acquisition was carried out between 400 and 1200 m. The bathymetric data were collected using a hull mounted Reson 8160 multibeam sonar. Resolution resulted in a 20x20 m implemented with 50x50 gridded size provided by a previously collected data. The seismic survey consisted of 6 dip-lines NNE-SSW run along the slope and 5 cross lines parallel to the slope totalling 170 km. Average spacing between diplines was slightly less than 1 km while spacing between crosslines was variable from 1.2 to 2.5 km. NNE-SSW and WNW-ESE directions. The acoustic source used was a 1Kjoule high-energy power supply system with a multitips (400) sparker array, fired at 2s time interval. RESULTS The collected data show that a wide submerged area of 350 km2, between 400 to 1200 m depths is undergoing slow-moving deformation and associated secondary mass wasting phenomena. Morphological features include trenches, counterscarps, bulging and both extensional and contractional features while internal deformations show typical landward dipping reflectors with strong evidence of synsedimentary faulting and asymmetric anticlines. Deformation processes operate at various scales generating folds with wavelength ranging from hundreds meters to kilometers. Extensional and rotational rupture surfaces sole out at various low-angle detachment planes located at depths from few hundred meters to 1 kilometer in subsurface. The internal organization of the failing mass shows different pattern of deformation that allows the identification of three main units: 1) a basal unit consisting of a very broad, asymmetric slump fold with a wavelength of about 5 km and amplitude of some 100 m. The fold axis is not vertical and the three dimensional interpretation indicates that the structure is not cylindrical. The fold strictly correlates with a morphological bulge seen on bathymetry at about 20 km south of Ischia Island. 2) A wedge shaped intermediate unit characterized by discontinuous and folded reflectors, locally showing basal detachment planes and compressional features. 3) A surficial slump unit affecting the upper and middle slope characterized by a basal decollément surface and normal growth faults that sole out at depths ranging from 70 to 40 m in subsurface. It is still unclear whether the landslide process can be favored by the volcano-tectonic evolution and rapid vertical accretion of Ischia volcano or is solely due to possibly volcanic spreading of the Ischia Island. REFERENCES CHIOCCI, F. L. & DE ALTERIIS, G. (2006) - The Ischia debris avalanche. First, clear submarine evidence in the Mediterranean of a volcanic island pre-historic collapse. Terra Nova, 18, 202–209. DE ALTERIIS, G., INSINGA D. ET AL. (2010) - Age of submarine debris avalanches and tephrostratigraphy offshore Ischia Island, Tyrrhenian Sea, Italy. Marine Geology 278 (2010) 1– 18. DE ALTERIIS, G. & VIOLANTE, C. (2009) - Catastrophic landslides off Ischia volcanic island (Italy) during prehistory. In: C. Violante, (ed.) Geohazard in Rocky Coastal Areas. Geological Society, London, Special Publications, 322, 73– 104. VEZZOLI, L. (1988) Island of Ischia. Quaderni de ‘La Ricerca Scientifica’ Progetto finalizzato ‘Geodinamica’, CNR Monografie finali, 10. VIOLANTE, C., BUDILLON, F., ET AL. (2004) - Submerged hummocky topographies and relations with landslides on the northwestern flank of Ischia island, southern Italy. In: ‘Occurrence and mechanisms of flow-like landslides in natural slopes and earthfills’, Sorrento, 14–16 May 2003. AGI, 2, 309–315

Architecture and Pliocene to Recent evolution of the offshore prolongation of the Granitola - Castelvetrano Thrust System (Sicily Channel)

High-resolution, seismic profiles were recorded in the offshore of Mazara - Punta Granitola with the purpose of reconstructing the architecture and Pliocene to Recent evolution of the south-west prolongation of the Granitola- Castelvetrano Thrust System, identified as an active structure possibly related to destructive historical earthquakes (Barreca et al., 2014; Ferranti et al., this meeting). A number of seismic units were identified. The oldest one is interpreted as representative of the Lower Pliocene pelagic deposits known in the region as Trubi. Lower-middle Pleistocene calcarenites are widespread along the continental shelf (CS) between Mazara del Vallo while their top rapidly deepens moving southeast-ward Capo Granitola. In this area, lower-middle Pleistocene calcarenites are unconformably overlain by the late Pleistocene- Holocene deposits. These latter are thin or absent NW of Punta Granitola along the CS, at water depth less than ~30 m, suggesting that this sector experienced uplift during the Quaternary. Small scale, NW- and SE-displacing reverse faults are observed along the CS where they cut the lower-middle Pleistocene calcarenites and offset the seafloor. South-eastwards, south-east-verging, reverse faults affect lower-middle Pleistocene calcarenites as well as the late Pleistocene-Holocene layers, suggesting that fault displacement acted during the post-LGM. Growth folding of Upper Pleistocene-Holocene deposits and thrust faults, predominantly dipping to the NW, affecting Pliocene rocks are observed in the immediate offshore Capo Granitola. The integration of the new data with those obtained from multi-channel profiles suggests that the active folds and thrusts are the uppermost expression of steep crustal ramps (Monaco et al., 1996; Lavecchia et al., 2007; Meccariello et al., this meeting) which upthrust the Saccense platform at depth

The submerged structure and stratal architecture of the Neapolitan Yellow Tuff (NYT) caldera, offshore the Campi Flegrei, (Eastern Tyrrhenian Margin): new insights from high resolution seismics and gravity core data

The Campi Flegrei is an active volcanic area defined by a quasi-circular depression that covers some 200 km2 of the coastal zone of SW Italy, a large part of which develops off the Naples (Pozzuoli) Bay (Fig. 1). The area has been active at least since 60 ka BP ( Pappalardo et al., 1999), and is structurally dominated by a caldera, 6 km in diameter, associated with the eruption of the Neapolitan Yellow Tuff (NYT), a 40 km3 Dense Rock Equivalent (DRE) ignimbrite (Scarpati et al., 1993) dated at ca 15 ka BP (Deino et al., 2004), that covered the district now occupied by the city of Naples, the Campi Flegrei and a large area of the continental shelf off the Pozzuoli Bay. The volcanological evolution of the NYT caldera as been long described on the basis of outcrop and subsurface studies onland (Rosi & Sbrana, 1987; Orsi et al., 1996, 2004 and references therein; Di Vito et al., 1999; Perrotta et al., 2006; Fedele et al., 2011), but its offshore morphology, detailed structure and recent stratigraphic setting are still poorly understood. In this study we integrate geological and geophysical data of different resolution/penetration obtained from high-resolution reflection seismic profiles (Sparker and Chirp source) with gravity core and swath bathymetry to better constrain the shallow structure, stratigraphic architecture and latest Quaternary to Holocene evolution of the submerged sector of the NYT caldera off the Pozzuoli Bay. Our data clearly image, for the first time, the offshore geometry of the NYT caldera ring-fault zone, as well as the style and timing of volcano-tectonic deformation associated with the late stage evolution of the NYT inner caldera resurgence. Our interpretation suggests that since 15 ka the offshore sector of NYT inner caldera underwent significant deformation and uplift (with minor subsidence episodes) that occurred at almost the same rate as the post-glacial sea-level rise. Particularly, the inner Pozzuoli Bay started to deform soon after 15 ka BP, when sea-level rise was initially faster than uplift. This caused a general increase of the accommodation space that was progressively filled up by volcaniclastic sediments. Since ca. 8 ka BP, along with the mid Holocene decrease in the rate of the sea-level rise, the early NYT resurgent structure was then uplifted up to the sea-level or even to partial subaerial exposure. From ca. 8 to 5 ka BP two distinct layers of volcaniclastic resediments, mostly represented by gravity flow deposits, formed throughout the Bay. A significant post- Roman (post 2 ka BP) subsidence phase of ca 10 m is then recorded offshore Pozzuoli by the drowning of the infralittoral prograding wedge below the present-day fair-weather wave base. REFERENCES Deino AL, Orsi G, de Vita S, Piochi M (2004) The age of the Neapolitan Yellow Tuff caldera-forming eruption (Campi Flegrei caldera—Italy) assessed by 40Ar/39Ar dating method. J. Volcanol. Geotherm. Res. 133, 157–170. Di Vito M., Isaia R., Orsi G., Southon J., de Vita S., D’Antonio M., Pappalardo L., Piochi M., 1999. Volcanism and deformation since 12,000 years at the Campi Flegrei caldera (Italy), J. Volcanol. Geotherm. Res. 91 (2-4), 221-246. Fedele L., Insinga D.D., Calvert A.T., Morra V., Perrotta A., Scarpati C., 2011. 40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity. Bull. Volcanol. 73, 1323-1336. Orsi G, de Vita S, Di Vito M, 1996. The restless, resurgent Campi Flegrei nested caldera (Italy): constraints on its evolution and configuration. J. Volcanol. Geotherm. Res. 74, 179–214. Orsi G., Di Vito M.A. Isaia R., 2004. Volcanic hazard assessment at the restless Campi Flegrei caldera. Bull. Volcanol. 66, 514–530. Pappalardo L., Civetta L., D’Antonio M., Deino A., Di Vito M., Orsi G., Carandente A., de Vita S., Isaia R. & Piochi M., 1999. Chemical and Srisotopical evolution of the Phlegrean magmatic system before the Campanian Ignimbrite and the Neapolitan Yellow Tuff eruptions J. Volcanol. Geotherm. Res. 91, 141-166. Perrotta A., Scarpati C., Luongo G., Morra V., 2006. The Campi Flegrei caldera boundary in the city of Naples. In: De Vivo B (ed) Volcanism in the Campania Plain: Vesuvius, Campi Flegrei and Ignimbrites. Elsevier, Amsterdam, pp 85–96 (in the series Developments in Volcanology, 9) Scarpati C., Cole P., & Perrotta A., 1993. The Neapolitan Yellow Tuff- A large volume multiphase eruption from Campi Flegrei, Southern Italy. Bull. Volcan. 55, 343-35

Measuring magnitude and rate of vertical movements in the offshore Capo Vaticano (W Calabria) using lowstand coastal prisms and wavebuilt terraces

The magnitude and rate of vertical movements have been measured in the offshore Capo Vaticano (western Calabria) for the Late Pleistocene - Holocene on the basis of the depth of submerged coastal prism and associated wave-built terrace formed during the sea-level lowstand of the Last Glacial Maximum (LGM). Uplifted and submerged terraces have proved to be valuable recorders of vertical motion in many locations around the world (e.g. DICKINSON, 2001; WEBSTER et alii, 2004) as the depth of their tops appear to be controlled by the sea-level. In the eastern Tyrrhenian margins, depending on the hydraulic energy conditions (i.e. waves and wind-induced currents), the average water depth of terraced surface of lowstand coastal prisms was probably 15-20 m (CHIOCCI & ORLANDO, 1996). A series of LGM lowstand coastal prisms and associated wave-built terraces were identified on a new set of very highresolution reflection seismic profiles acquired along the continental shelf and upper slope of the western Calabria continental margin. Data processing included time-depth conversion and the interpretation of the resulting seismic lines was performed using a GIS-based software package. Seismic interpretation highlight that along the offshore Capo Vaticano the slope-breaks associated with wave-built terraced formed during the LGM deepens from ~130 m (cluster A) to ~170 m (cluster B) below sea level (bsl) as one moves from southwest to the northeast, over a distance of ~21 km (Fig. 1). Farther to the north, along the western flank of the Calabrian Arc, an average depth for the slope-breaks of ~165 m is measured. Removal of the non tectonic component of vertical changes using an ice-volume equivalent eustatic sea-level compilation (LAMBECK et alii, 2011) indicates ~15 (± 5) m of uplift and ~25 (± 5) m of subsidence during the post-LGM for the southern and northern sectors offshore Capo Vaticano, respectively. The resulting average uplift and subsidence rates (both regional and local components) for the last 20 (± 2) k.y. are 0.75 (±0.325) mm/y and 1.25 (±0.375) mm/y, respectively. The integration of the new data with those available in the literature (e.g. TORTORICI et alii, 2003; CUCCI & TERTULLIANI, 2010; FERRANTI et alii, 2011) may provide information on fault kinematics and constraints on slip rates of tectonic structures that are relevant for earthquake hazard analysis of western Calabrian margin. REFERENCES CHIOCCI, F. L. & ORLANDO L. (1996) - Lowstand terraces on Tyrrhenian Sea steep continental scope. Marine Geology, 134, 127-143. CUCCI, L. & TERTULLIANI A. (2010) - The Capo Vaticano (Calabria) coastal terraces and the 1905 M7 earthquake: the geomorphological signature of regional uplift and coseismic slip in southern Italy. Terra Nova, 22, 378–389. doi: 10.1111/j.1365-3121.2010.00961.x DICKINSON, W.R. (2001)- Paleoshoreline record of relative Holocene sea levels on Pacific islands. Earth-Science Reviews, 55, p. 191–234. doi: 10.1016/S0012-8252 (01)00063-0. FERRANTI L., SCICCHITANO G., SPAMPINATO C. R., ANTONIOLI F., MONACO C. (2011) - Holocene coastal uplift at Capo Vaticano, Calabria: implications for differential deformation rates. Riassunti VIII Forum FIST Geoitalia 2011, 19-23 Settembre 2011, Torino. Epitome, 4, 153. LAMBECK, K., F. ANTONIOLI, M. ANZIDEI, L. FERRANTI, G. LEONI, G. SCICCHITANO & S. SILENZI (2011) - Sea level change along the Italian coast during the Holocene and projections for the future. Quaternary International, 232, 250-257. WEBSTER, J.M., WALLACE, L., SILVER, E., APPLEGATE, B., POTTS, D., BRAGA, J.C., RIKER-COLEMAN, K. & GALLUP, C. (2004) - Drowned carbonate platforms in the Huon Gulf, Papua New Guinea. Geochemistry Geophysics Geosystems, 5, p. Q11008, doi: 10.1029/2004GC000726. TORTORICI, G., BIANCA, M., DE GUIDI, G., MONACO, C. & TORTORICI, L. (2003) - Fault activity and marine terracing in the Capo Vaticano area (southern Calabria) during the Middle-Late Quaternary. Quatern. Int., 101–102, 269–27

Plio-Quaternary tectonic evolution offshore the Capo Vaticano Promontory

We reconstruct the Plio-Quaternary tectono-stratigraphic evolution in the offshore Capo Vaticano (W Calabria, Italy) by integrating data obtained from single- and multi-channel reflection seismic profiles and a reprocessed version of the CROP M2A/III line. NW-trending, high-angle normal faults, dipping ~70° to the south-west formed along the continental slope connecting the south-west continental shelf of the Capo Vaticano Promontory to the Gioia Tauro Basin (Pepe et al., 2014). Faults generally have small displacements up to 40 m and are sealed by Pleistocene deposits. West of the Capo Vaticano promontory and in the Gioia Basin, a SE-dipping, normal fault system, more than 32 km long, is recognized. Faults affect lower (?) Pleistocene and are sealed by probably post-0.7 Ma deposits. These faults are here tentatively interpreted as the antithetic faults of major, Late Pliocene to Quaternary, NW-dipping, normal faults, which form the currently active tectonic belt along the Calabrian Arc (e.g. Monaco and Tortorici, 2000; Faccenna et al., 2011). In the Santa Eufemia Gulf, reverse faults affecting Plio-Quaternary and older sedimentary successions are observed. Faults also offset the seafloor thus indicating their recent activity. A normal fault system has been also inferred on the basis of the present day depth variations of the edges of submerged depositional terraces and associated abrasion platforms, along which a vertical displacement of ~21 m during the Late Pleistocene-Holocene has been inferred. The information derived in offshore the Capo Vaticano Promontory represents an important step towards an accurate 3-D kinematic description of the tectono-stratigraphic evolution of the western (Tyrrhenian) side of the Calabrian Arc orogenic wedge during the Plio-Quaternary

Architettura stratigrafica ed evoluzione del Golfo di Pozzuoli negli ultimi 15 ka:una nuova prospettiva sulla caldera del Tufo Giallo Napoletano,Campi Flegrei, margine tirrenico orientale.

I Campi Flegrei rappresentano un distretto vulcanico attivo che si sviluppa al confine tra il settore emerso e sommerso del margine continentale campano. Il distretto vulcanico occupa una superficie di circa 200 km2, è strutturalmente dominato da una caldera di collasso del diametro di circa 8 km formatasi in seguito all’eruzione del Tufo Giallo Napoletano (TGN), un deposito ignimbritico del volume di 30-50 km3 Dense Rock Equivalent, datato a 15 ka B.P. circa, ed è attivo da almeno 78 ka B.P circa. L’obiettivo di questo lavoro è di ricostruire l’architettura stratigrafica e l’evoluzione vulcanotettonica tardo-Quaternaria del sistema caldera di collasso - faglia anulare - risorgenza intra-calderica del settore sommerso della caldera del TGN. A tal fine è stata analizzata una fitta maglia di profili sismici a riflessione monocanale di alta (Sparker) ed altissima (Subbottom Chirp) risoluzione. I dati sismici sono stati successivamente integrati sia con quelli ottenuti dall’analisi di carotaggi a gravità e batimetrici multibeam che con quelli disponibili in letteratura e, nell’insieme, analizzati in ambiente GIS. I nuovi dati indicano che il settore interno dell’area collassata a seguito dell’eruzione del TGN evolve inizialmente in condizioni di mare basso. L’area intra-calderica viene successivamente interessata dalla formazione di una struttura antiforme (risorgenza intra-calderica) il cui tasso di sollevamento è stato comparabile con l’innalzamento eustatico nell’intervallo Pleistocene superiore – Olocene [Lambeck et al., 2011]. A circa 10 ka B.P. il settore centrale della struttura risorgente raggiunge l’esposizione subaerea (terrazzo morfologico de “La Starza”). La calibrazione dei profili sismici Chirp con markers tefro-stratigrafici riconosciuti in un carotaggio e datati al 1538 A.D., 79 A.D. indica l’instaurarsi di un periodo di subsidenza in epoca post-Romana, registrato dall’annegamento di 10-25 m del cuneo di progradazione infralittorale rispetto alle profondità di equilibrio funzionale attualmente segnalate in area Mediterranea. L’interpretazione sismostratigrafica rivela, inoltre, la presenza di fluidi che risalgono attraverso la zona di faglia anulare che delimita la caldera del TGN. Bibliografia Lambeck, K., Antonioli, F., Anzidei, M., Ferranti, L., Leoni, G., Scicchitano, G., Silenzi, S., (2011). Sea level change along the Italian coast during the holocene and projections for the future. Quaternary International, 232, 250-257

Ampiezza e tassi dei movimenti verticali a Capo Vaticano (Calabria occidentale,Italia) negli ultimi 20 mila anni determinati sulla base di cunei progradanti epiattaforme di abrasione.

Ampiezza e tassi dei movimenti tettonici verticali sono stati quantificati nel settore offshore di Capo Vaticano (Calabria occidentale), nell’intervallo Pleistocene superiore – Olocene, sulla base delle profondità del ciglio dei cunei progradanti infralitorali e delle piattaforme di abrasione formatesi durante l’ultimo massimo glaciale (LGM). I cunei progradanti sono stati riconosciuti in profili sismici a riflessione ad alta risoluzione Sparker. I dati sismici sono stati acquisiti lungo la piattaforma e la scarpata continentale superiore, durante le crociere oceanografiche Marisk 2010 e 2012 organizzate dall’IAMC del CNR di Napoli, il DISTEM dell’Università di Palermo e il Dip. di Scienze della Terra dell’Università di Napoli. La deformazione tettonica verticale del promontorio di Capo Vaticano e del suo prolungamento offshore è caratterizzata da una marcata asimmetria, con profondità dei cigli dei cunei infralitorali che si approfondisce progressivamente procedendo verso NE. La rimozione della componente non tettonica dei movimenti verticali, ottenuta utilizzando dati sulle variazioni glacio-eustatiche del tardo Quaternario [Lambeck et al., 2011], indica nell’area in esame ~11 (± 5) m di sollevamento e di ~25 (± 5) m di subsidenza, nell’intervallo post-LGM, muovendoci da sud-ovest verso nord-est, su una distanza di ~22 km. Il valore medio del tasso di sollevamento e di subsidenza (considerando la componente sia regionale sia locale) per gli ultimi 20.350 (± 1,35) anni sono pari a 0,52 (± 0,28) mm/anno e di 1,23 (± 0,32) mm/anno, rispettivamente. I valori dell’ampiezza e il pattern dei movimenti verticali ottenuti attraverso l’analisi dei cunei progradanti infralitorali sono comparabili, sebbene a tassi parzialmente differenti, sia con quelli determinati attraverso marker geomorfologici tardo Olocenici [Spampinato et al., 2012] che con i tassi di sollevamento a lungo termine calcolati sulla base delle posizioni dei terrazzi marini formatisi a 80 a 215 mila anni [Cucci & Tertulliani, 2010]. L’integrazione dei nuovi dati con quelli disponibili in letteratura indica che il basculamento del promontorio di Capo Vaticano è episodico ed è avvenuto principalmente tra 215 e 125 mila anni e nel post-LGM