New gravity data and thickness estimate in the Gubbio Quaternary basin, Northern Apennines, Central Italy

We present new gravity data over the Gubbio basin (central Italy), a Quaternary extensional basin at the hanging-wall of the SW-dipping Gubbio normal fault. We acquired 367 new gravity stations in the basin and its immediate surroundings, improving the density coverage up to 5 stations per square km (previous data had 1 station per square km). Such data were corrected according to standard procedures and were used to calculate the Bouguer anomaly map of the basin. Once removed the regional signature, we use the residual Bouguer anomaly to estimate the thickness of the basin infill (i.e. depth to the bedrock). The results are in agreement with previous estimates made from seismic data. As opposed to previous hypothesis, the thickness of the basin is asymmetrical, from the depocenter (maximum thickness of ∼600 m), roughly corresponding to the geographic center of the basin, the thickness of the infilling deposits rapidly decreases towards the south to an average of ∼150 m, while northwards it is ∼350 m. These data provide new insights on the tectonic and sedimentary evolution of the basin and, in turn, on the temporal and spatial evolution of the Gubbio Fault.