Syndepositional deformation of the Lastoni di Formin carbonate platform (Italy) from Virtual Outcrops and field studies

Abstract

Summary In recent years, the evolution of Unmanned Aerial Vehicles (UAV), together with advances in photogrammetry and Structure from Motion techniques (SfM) have enhanced the role of Digital Outcrop Models (DOM) in fracture studies, due also to the possibility to obtain accurate 3D measurements from large and inaccessible areas. In this work, we applied the Digital Outcrop Model techniques, developed by UAV Photogrammetry, to the study of fracturation of a strongly prograding carbonate buildup in the Dolomites. About 250 fault and fractures where measured from the Digital Model, and more than 400 fracture trends were collected in the field , both on the platform-top surface and in the overlying Heiligkreutz formation. Opening mode joints and neptunian dykes, orthogonal to the direction of progradation (i.e. margin parallel) were detected at seismic scale and in the field, and interpreted as early-stage fractures. Moreover, the carbonate body records two main tectonic events, which contribute to form the present-day fracture network: the Jurassic extension, forming N-S trending joints and normal faults, and the Alpine compressive phase. Syndepositional fractures are preferentially reactivated in strike-slip, showing that their orientation with respect to the stress field can influence the subsequent evolution of the fracture pattern.