Abstract

Geometric and kinematic attributes as well as the spatial distribution of fault-related fractures from carbonate rocks of the Southern Gargano have been sampled and analysed. The Gargano Promontory, the spur of the Italian Peninsula, is a structural high located in the southern sector of the Adriatic plate which has acted as the foreland of the Apenninic thrust-and-fold belt. The area contains a thick Meso-Cenozoic marine carbonate succession forming a wide WNW-ESE anticline. Here, three major, subvertical faults have been recognised and studied: the E-W Mattinata and Rignano faults and the WNW-ESE Candelaro Fault. The analysis allowed to recognise two main types of fault-related brittle deformations: solution cleavages and meso-scale faults. The use of a specifically developed methodology for the analysis of the fracture spatial distribution has allowed us to define a rather constant geometric relationship between the main faults and the associated cleavage surfaces. We propose an origin model for the fault-related cleavage as solution surfaces initiating in the region ahead of the fault propagating tip. This model is consistent with a left-lateral, strike-slip first-generation of the studied faults. Analyses of the geometry and kinematics of the meso-scale faults support this hypothesis and reveal reactivation processes which occurred along the Rignano and Candelaro faults as subvertical motions. New constraints on the post-Miocene succession of deformation events have been established within the framework of the regional transpression regime controlling: 1) the development of the Gargano anticline, 2) the formation of the left-lateral strike-slip faults, 3) the reactivation, by subvertical to extensional dip-slip motions of some of the early-formed faults.

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