Analysis of gravity disturbance data for the detection of crustal-scale structures: insights from central Italy and surrounding regions

North-central Italy is cored by the Apennines mountains, which are the product of Cenozoic convergence between the Adriatic microplate and the European plate. The Apennines display complex lateral variations in surface geology, some of which could be associated with a postulated yet controversial tear in the subducting Adriatic lithosphere. This research uses spectrally filtered World Gravity Model (WGM) 2012 gravity disturbance data to highlight linear changes in the data at different inferred depths, interpreted as proxies for location of crustal-scale geological structures. Gravity “worms” (multiscale wavelet edges of the gravity disturbance data) are used to supplement lineament interpretation and emphasize structural contacts. Results show that while the lineament characteristics vary at three different depth intervals (~2-25 km, ~25-50 km, and >50 km), certain major lineaments are continuously expressed. The study area is additionally subdivided into five major domains corresponding to different dominant orientations of the gravity lineaments. The lineament patterns within the domains likely highlight major structures in regions that experienced contrasting tectonic evolutions leading up to the present-day configuration. Furthermore, the gravity lineaments at all three inferred depth slices tend to show a spatial correlation with major lithological boundaries. Gravity lineaments at the shallow depth slice spatially correlate with surficial features such as the edges of Neogene-Quaternary sedimentary basins, topographic ridges in the surrounding Tyrrhenian, Ligurian, and Adriatic seas, as well as geomorphological features in the Northern Apennines. The lineaments in the shallow and intermediate depth slices tend to align with major thrust faults across the study area, as well as with transverse lineaments that have been well-documented in the northern Apennines. The lineaments in the deepest slice appear to align with seismicity patterns. Finally, a set of gravity lineaments, imaged across all three depth slices, is consistent with the location of the postulated subduction tear in the Northern Apennines, thereby supporting this hypothesis. Our results suggest that analysis of lineament patterns from gravity disturbance data is a powerful tool to detect lithospheric-scale structures and identify domains that can provide insight into the tectonic evolution of a complex area.