GNGTS 2013 - Atti del 32° Convegno Nazionale

faults. The G2 marine seismic unit is characterized by wedging and growth in correspondence to the above mentioned anticlines and synclines. The Capo Miseno seismic unit is deformed in correspondence to both the slopes of the bank by normal faulting. A structural depression is individuated under the volcanic edifice of Capo Miseno, in which a thick pyroclastic unit deposits. Conclusions. TheGulf of Pozzuoli represents the submerged border of the Phlegrean caldera, resulting from the volcano-tectonic collapse induced from the pyroclastic flow deposits of the Campanian Ignimbrite (35 ky B.P.). Several morpho-depositional units have been identified, i.e., the inner continental shelf, the central basin, the submerged volcanic banks and the outer continental shelf. The stratigraphic relationships between the Quaternary volcanic units related to the offshore caldera border and the overlying deposits of the Late Quaternary depositional sequence in the Gulf of Pozzuoli have been highlighted. Fourteen main seismic units, both volcanic and sedimentary, tectonically controlled due to contemporaneous folding and normal faulting have been revealed by geologic interpretation. These units are herein resumed, from the oldest to the youngest. The V3 unit, located in the Pozzuoli Gulf is characterized by acoustically transparent to discontinous seismic facies and is strongly eroded at its top. It is a volcaniclastic unit related to the northern margin of the Pentapalummo bank. The G3 unit, located in the Pozzuoli Gulf is characterized by discontinuous to parallel seismic reflectors, representing the lower sedimentary unit of the basin fill, composed of clastic deposits. The pyr1 unit, located in the Eastern Pozzuoli Gulf, is characterized by discontinuous to sub- parallel seismic reflectors. It represents a pyroclastic unit, uncertain in attribution, deposited in a structural depression under the Capo Miseno volcanic edifice. The dk unit is represented by sub-vertical volcanic bodies, acoustically transparent and locally bounded by normal faults. This unit, detected in the eastern and central Pozzuoli Gulf, is represented by volcanic dykes due to magma uprising in correspondence to normal faults, as already suggested for the whole Naples Bay (Fusi, 1996; Fusi et al. , 1991). The pyr2 unit, interpreted in the eastern Pozzuoli Gulf, is characterized by a seismic facies with continuous progradational to parallel seismic reflectors. This pyroclastic unit, uncertain in attribution, has been deposited from the offshore surrounding the Capo Miseno volcanic edifice to the Miseno volcanic bank. The lsl1 unit is represented by a wedge-shaped, chaotic to discontinuous seismic unit, occurring in the eastern Pozzuoli Gulf. It is represented by a wide palaeo-landslide, overlying the V3 volcaniclastic unit and coeval with the basal part of the G2 marine unit. The G2 marine unit, identified in the Pozzuoli Gulf, is characterized by parallel and continuous seismic reflectors. It represents the intermediate unit of the basin fill, probably composed of clastic deposits. The NYT/PC seismic unit is a complex volcanic unit recognized in both the Naples and Pozzuoli Bays. The NYT unit is represented by the pyroclastic deposits of the Neapolitan Yellow Tuff (12 ky), showing a wedge-shaped, acoustically transparent, volcanic seismic unit. The PC unit is characterized by a seismic facies with mound-shaped, acoustically-transparent, volcanic bodies interlayered with parallel reflectors. The PC unit is represented by the tuff cones of the Nisida volcanic complex in facies hetheropy with the Neapolitan Yellow Tuffs and interstratified with the G3 marine deposits. The lsl2 unit is represented by a wedge-shaped, chaotic to discontinuous seismic unit. It is represented by a fossil landslide overlying the G2 marine unit and underlying the Lowstand System Tract of the Late Quaternary depositional sequence and has been interpreted in the eastern Pozzuoli Gulf. The G1 marine unit is characterized by a seismic facies with parallel and continuous seismic reflectors and has been detected in the whole Gulf of Pozzuoli. It represents the upper sedimentary unit of the basin fill, attaining a maximum thickness in the depocenter of the central basin. The LST seismic unit is characterized by progradational seismic reflectors, erosionally truncated at their top. It represents the lowstand system tract of the Late Quaternary depositional sequence and has been detected in the inner continental shelf off Pozzuoli. The lsl unit is a wedge-shaped, chaotic to discontinuous, seismic unit, detected in the Gulf of Pozzuoli, south of the Miseno Cape. It is represented by landslide 10 GNGTS 2013 S essione 3.1