Facies analysis, vertebrate paleontology and palynology in the Late Miocene Baccinello-Cinigiano basin (Southern Tuscany)

In the Baccinello-Cinigiano basin, a fluvio-lacustrine succession is exposed overlying bedrock consisting of mainly calcareous Ligurian units and of turbiditic sandstones of the Macigno Formation. The fluvio-lacustrine sedimentary cycle is attributed to the Upper Miocene (Upper Tortonian-Messinian). Sediments of the marine transgression, Early Pliocene in age, unconformably overlay the fluvio-lacustrine succession. Results of an integrated study on the sedimentology, palynology, and mammal faunas of the Late Miocene sedimentary cycle are presented in this note. Five lithological units (A - E) are described and interpreted. Comparative analysis makes possible the recognition of some significant events that controlled its sedimentary evolution. Tectonic control strongly influenced the opening and the early filling stage (unit A), the last filling stage (unit E) and, in part, the deposition of unit C. The climatic signature on deposition produced a distinct trend during deposition of units B, C and D, from warm and humid conditions to an inconsistent regime with irregularly alternating dry and moist phases.