Continental to marine Quaternary deposits outcrop in thin and patchily exposed successions in Western Sicily,overlying a previously deformed substrate, known as the Neogene-Early Quaternary chain. These deposits aregrouped in sedimentary units bounded by unconformity surfaces. The detected unconformities, often of regionalextent, allows us to define seven main synthems: a) Marsala synthem is a Lower Pleistocene 2-80 m-thick bodyof marine/coastal calcarenites; b) Piana di Partinico synthem is made up of 1-5 m thick marine/continentalclastics located on several marine terraces related to sea level highstand phases of Middle Pleistocene (OxygenIsotope Stages – OISs - 17-7); c) Polisano synthem consists of aeolian sands, 1-10 m-thick, of late MiddlePleistocene (OIS 6); d) Barcarello synthem encompasses 1-2 m thick marine/coastal deposits, laterally passinginto 1-5 m thick colluvial deposits, whose age is correlated with the OIS 5; e) Imera Settentrionale synthem ismade up of Middle–Upper Pleistocene 1-3 m-thick fluvial deposits located on river terraces; f) Raffo Rossosynthem is composed of aeolian sands, colluvial, gravitational and stratified slope deposits (OISs 4-2); g) CapoPlaia synthem consists of coastal to continental deposits of Holocene age (OISs 2-1).The processes of deposition or erosion producing sedimentary bodies or unconformity surfaces, respectively,seem to be triggered by significant environmental changes due to tectonic movements and climatic fluctuations.The interplay of these factors suggests the following evolution: a Lower Pleistocene block faulting induceddisplacements of hundreds of meters allowing the development of marine erosion transgressive surfaces andshallow-water sedimentation of the Marsala synthem; the interplay between tectonic uplifting and sea levelhighstand phases, during Middle-Late Pleistocene, gave rise to several orders of marine and river terraces,where the Piana di Partinico, Barcarello and Imera Settentrionale synthems deposited. In this period, aeolian andstratified slope deposits of Polisano and Raffo Rosso synthems were accumulated above non-depositionalsurfaces, during cold climatic events; the triggering of strong sheet erosion and sheet flood produced subaerialerosion surfaces and colluvial deposits of the Piana di Partinico, Barcarello and Raffo Rosso synthems, duringsemi-arid climatic events.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2011|