Plio-Quaternary tectono-stratigraphic evolution of the Paola fore-arc basin (western Calabria continental margin): Insight from high-resolution seismic reflection data

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Abstract

We reconstructed the most relevant geologic features across the Paola Basin (offshore western Calabria) and itsPliocene to Recent sedimentary and tectonic evolution using a grid of seismic profiles acquired within the frame of theEU-SINBUS project in the 1995. We used seismostratigraphic analysis to outline the seismic units. The Messinianhorizon, as well as regional unconformities recognized in the Plio-Pleistocene geological record of the basins developedwithin or adjacent to the Calabrian Arc, played a key role to assign ages to the sedimentary units. We identified fiveseismic units on seismic lines, based on the internal configuration and seismic-stratigraphic character of reflectors(amplitude, reflection continuity, external shape, and frequency). Moving from the Calabria coast-line to the west, thePaola Basin can be partitioned into two sectors characterized by different Plio-Quaternary tectonic deformation separatedby a NNW-SSE elongated area that coincides with the basin depocenter. Plio-Quaternary high-angle, reverse faults arewidely spread over the western sector of the basin that correspond to an arcuate ridge separating the basin from the Marsiliabyssal plain. A high-angle, NNE-trending, normal fault system, on the contrary, developed on the south-west tip of thebasin only, where the fault offset deforms the Messinian horizon of ca. 500 m. Data suggest that limited vertical slipoccurs along reverse faults detected at the border and inside the sedimentary infilling of the Paola Basin, reachingthickness of more than 3.8s two way travel time. A series of acoustically opaque cone-shaped zones on the western flanksof the basin interrupts the continuity of the sequences. These zones, 2 km-wide, propagate to the surface intruding thelower sequence and folding both the sedimentary layering of the upper sequence and the sea-floor. The featurescorrespond to intruded and erupted mud diapirs that pierce the entire sequence because of the occurrence of overpressuredfluids escaping to the surface via any permeable horizons and tectonic structures. The sequences reflection pattern can beinterpreted as the result of the infilling of thrust-top basin related to a prograding system located between a growth rampanticlineto the west and a culmination of basement-thrust sheets to the East, activated in the context of the TyrrhenianSea opening and lateral escape of the Calabrian block. Thus, mechanisms for subsidence affecting this area since the LateNeogene significantly differ from extensional and/or compressional processes responsible for formation of basins alongthe Sardinia and northern Sicily continental margins. Taking into account the pattern of the sedimentary infilling, thebasin shape and its position in the regional context, we propose that the Paola Basin developed near the northern edge ofthe Ionian slab where tearing of the lithosphere is expected.
Lingua originaleEnglish
Numero di pagine1
Stato di pubblicazionePublished - 2016

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