Gli strati a <<congerie>> del messiniano superiore del margine nord-occidentale ibleo. Caratteristiche faunistiche e possibili implicazioni paleogeografiche e paleoclimatiche.

Along the northwestern margin of the Hyblean Plateau (SE Sicily), Early Messinian sediments consist of lime mudstones of lagoonal or peritidal environment which rest above Tortonian marls and volcanics. These carbonates display a close lithological and faunal similarity with the coeval shallow shelf Mt. Carrubba Fm carbonates exposed on the eastem areas of the plateau. Messinian evaporites consisting of swallow tail gypsum, are hosted inside growing structural depressions and are aligned NE-SW, according to the principal tectonic trends controlling the northem and northwestem leading edges of the Plateau. Following the evaporite deposition, conspicuous rates of subaerial weathering took place, triggering major erosional processes and topographyc leveling. Dissolution features are developed above the earlier Messinian evaporites and limestones with local development of karstic autobreccia. A widespread, although thin, fluviatile conglomerate and lacustrine marl cover was laid above carbonate breccias and older sediments. Gastropods and «Congeria» faunas typify these oligohaline to freshwater deposits, which at places are capped by thin subaerial lava flows. Climatic conditions were characterized by extreme aridity which prevented the occurrence of carbonate and/or siliciclastic contaminants within the evaporites. In contrast both the occurrence of the Late Messinian faunal assemblage and its related palaeoecological and palaeoenvironmental implication, suggest warm temperate climatic conditions during the succeeding Late Messinian, The main results which stand out from the study carried out on the Late Messinian sediments and fauna of the northwestem Hyblean region, fit well other palaeogeographic and palaeoclimatic interpretations for the Late Messinian environment as tasted elsewhere in the main central Sicilian evaporite basin