UPPER MIOCENE EXTENSIONAL TECTONICS AND SYN-RIFT SEDIMENTATION IN THE WESTERN SECTOR OF THE VOLTERRA BASIN (TUSCANY, ITALY)

Abstract

This paper analyses the tectonic-sedimentary evolution of the northwestem portion of the upper Miocene- middle Plio­cene Volterra basin. The studied area lies between Chianni and Orciatico villaies, along the Sterza valley. The upper Torto­nian - lower Pliocene succession consists of two unconformi­ty bounded stratigraphic units (UBSU). The first, upper Tor­tonian - lower Messinian, is made up of oontinental to transi­tional environment clastic deposits. The second UBSU, up­per Messinian - lower Pliocene, features continental clastic deposits in the lower porti on, and lower Pliocene marine clas­tic sediments in the upper one. [...]