Basin deformation due to laccolith emplacement at Radicofani (Southern Tuscany, Italy)

Abstract

The Radicofani basin (Southern Tuscany), developed during regional extension, is mainly filled by a mio-pliocene clastic sequence. During Early Pleistocene, the Radicofani spatter cone formed in the centre of the basin. A broad anticline, whose formation was previously associated with both extensional and compressional tectonics, is present within the basin. In order to better define the anticline, we collected field, seismic and magnetic data. Field work constrained the surface geometry of the anticline, showing that the Radicofani vent is located along the trace of its axial plane. Seismic lines are consistent with field data and show a progressive decrease in the dip of the anticline layers towards the bottom of the Neogene succession. The measured magnetic field shows a systematic relationship with the anticline, suggesting the association with a buried magnetic body. The matching of these data suggests that the anticline is the result of the emplacement of a laccolith within the Radicofani basin, possibly related to the magmatic activity responsible for volcanism at Radicofani.