L'EVOLUZIONE TETTONICO-SEDIMENTARIA MIOCENICA DELL'AREA DI SERRA SAN QUIRICO - FRONTALE (MARCHE CENTRALI)**

Abstract

The studied area represents the eastem limb of the Aliforni Syncline, at the foot of the Mount San Vicino Anticline (Apiro, Marche Apennines, central Italy). The detailed geologica! survey allowed to recognize that the present setting of Messinian Units originated mainly as a consequence of the Late Miocene tectono­sedimentary evolution of the area. During the beginning of Messinian, silicoclastic turbiditic sandstones (Laga Formation), few hundreds of m thick, filled small troughs originated by tensional tectonic. The sandstone deposition did not occur in the horsts, so the basin roughness was gradually reduced. The evaporitic event in the area is represented mainly by euxinic marls, while the recharge of turbidi tic deposits strongly reduced. The evaporitic Unit (Gessoso Solfifera Formation) over­lies the Laga Formation or directly the pre-messinian Units through an unconforrnity surf ace, but in this peri od sure evidences of acti­ve tectonic lack inside the basin. [...]