GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 1.1 189 Fig. 2 – Geological Map of the Catania region (for location see box in Fig. 1). Castello (Fig. 2), is deeply incised by NW-SE oriented consequent valleys that are completely infilled with the Late Pleistocene-Holocene Etnean lava flows (Monaco et al. , 2000). Catania-Acicastello terraced slope. The terraced slope of the coast from Catania to Aci Castello is the result of the tectonic uplift, since the Late Pleistocene, at the footwall of an active normal fault belt located in the Ionian offshore (Monaco et al. , 2002; Catalano et al. , 2004; 2008). However, the new collected geological data from the northern part of Catania and the adjacent San Gregorio and Aci Castello areas (Fig. 2) evidenced the primary Middle Pleistocene geometry of the culmination (profile 3 and 4 in Fig. 3; see Fig. 2 for location). Across the coastal slope, impressive fold deformation affects the sedimentary substratum and the Middle Pleistocene lava flows, which are unconformably covered by the Late Pleistocene to Holocene marine terraces and lava flows. A clear flexure affects the marly-clays substratum and the associated submarine tholeiitic lavas, cropping out in the coastal slope of Aci Castello (profile 4 in Fig. 3). In the upper part of the slope, the tholeiitic lavas are interleaved in the marly-clays succession that is gently dipping towards the SE. The lava horizon, on a distance of about 700 m, decreases in elevation from 230 to 100 m a.s.l., forming a gentle asymmetric syncline. The same lava horizons, at the base of the slope, form an antiformal flexure, connecting the levels that crops out at an elevation of about 100 m a.s.l. with those lying along the coast of Aci Castello. More to the south, the interpretation of the well logs from two boreholes (P1 and P2 in Fig. 2) demonstrates the occurrence of the antiformal flexure also in the area from San Gregorio to Catania (profile 3 in Fig.3; see Fig. 2 for location). In this transect, the upper part of the slope shows the ancient lava flows (140 ka; Branca et al. , 2011) that rests on the sands of the OIS 7 marine terrace (240-200 ka), unconformably covering the marly clay substratum. The lower