Minéraux argileux de la zone de Sclafani (Madonies, Sicile) : diagénèse et paléoenvironnement du Permien au Miocène

Abstract

Clay minerals of Sclafani zone (Madonies, Sicily) : Permian to Miocene diagenesis and paleoenvironment. The Permian to Miocene clay mineral successions identified in the Sclafani zone (North Sicily) proceed from various diagenetic and paleogeographic influences, each of them being sometimes difficult to distinguish. The depth of burial mainly controls the Permo-triassic series. The post-triassic deposits reflect both diagenetic and paleoenvironmental effects. The Liassic and Cretaceous distensive stages are marked by increasing supply of illite and associated rock-derived minerals . Chemical influences probably result from volcanic activity during the Dogger, and from ionic sedimentary concentration during Eocene. The Numidian flysch shows a mineralogical diversification and large amounts of kaolinite, pointing to the continental erosion of both rocks and soils. The molassic deposits differ from flysch deposits by the smectite abundance and the kaolinite rareness, a character permitted by the presence of low relief and hot climate. The average warm clima¬ tic conditions since the Triassic are documented by the scarcity of chlorite compared to kaolinite and smectite.