Stratigraphic, diagenetic and provenance implications from mineralogical and geochemical study of the Montefortino section (Lower-Middle Miocene, central Italy)

A compositional study (mineralogy and geochemistry) was carried out on marine formations of the Umbria-Marche succession (foreland domain of the Apennines), composed of pelagic/hemipelagic sediments ranging from Early Aquitanian to Tortonian. The time interval encompasses important environmental changes mainly due to volcanic activity, proliferation of siliceous organisms, and clay minerals supply. The basin evolution can be summarized in 3 main compositional changes: 1) beginning of volcaniclastic sedimentation, followed by the proliferation of siliceous organisms (base of the section); 2) end of volcaniclastic and siliceous input; 3) change in siliciclastic composition, due to higher smectite content in the upper part of the section.