Stratigraphy and basin-fill architecture of the Plio-Pleistocene Catania Plain foredeep basin (eastern Sicily: a preliminary synthesis.

Eastern-central Sicily is occupied by the present Catania-Gela foredeep alignment. This marks the contact between the Hyblean plateau and the Maghrebian thrust belt, as the result of the collision between the African foreland and the European southern margin during Tertiary times. The Catania Plain represents the easternmost Sicilian sector of the Quaternary foredeep basin. The present study attempts to reconstruct the Pleistocene to recent stratigraphic history of the Catania Plain foredeep basin. The utilised data set consists of several well log data compared with field observations conducted along the basin margins, where the oldest Quaternary successions crop out. Also, seismic off-shore data were considered in this study. The measurement of six geological cross-sections through the eastern sector of Catania Plain foredeep basin has pointed out the main depositional features of the Pleistocene-Holocene stratigraphic record. The results show that the sedimentary evolution of the Catania Plain foredeep basin is characterised by four main depositional sequences, with similar architecture relative to other foredeep basins in the central Apennines. These sequences are: (a) a marine muddy inner-shelf sequence ( “Argille Marnose Grigio-Azzurre”, Auct.), up to 600 m thick, assigned to the Sicilian; (b) a sandy-gravelly shoreface sequence (“Sabbie e Ghiaie di S. Giorgio”, Auct.) of Mindell-Riss age; through an unconformity surface, also recognised by seismic off-shore data, this succession evolves to alluvial-marine gravelly deposits (c) of Tyrrhenian age (“Ghiaie e Conglomerati di Mt. Tiritì”, Auct.) characterised by a centripetal depositional trend. The Holocene record is closed at the top by a fourth depositional sequences (d) constituted by Simeto River and minor tributaries succession, represented by alluvial clay, sand and silt, with recent and present coastal sediments in the eastern part of the study area interbedded. The depocenters of the four depositional sequences migrated southward in time, along the sector of the Catania Plain. This migration was synchronous to propagation of the Gela Nappe thrust front, covered at present by the investigated sedimentary succession. The strong uplift ratio, estimated for the sector in 1.4 mm/y starting from 330 ky BP, and sea-level variations during the Quaternary give the Catania Plain stratigraphic infill a quite complex foredeep multi-phase developed appearance.