Several orogenic belts exhibit regional-scale anticlines characterized by prominent faults in their crestal/forelimb zone. These faults are also a common feature in the Neogene fold-and-thrust belt of the Apennines, where they have been contrastingly interpreted as younger-on-older thrust faults, large-scale strike-slip faults, and pre- or syn-thrusting normal faults. In this study, we analysed a NW–SE-trending fault (Montagna dei Fiori Fault) that affects the hinge-zone/forelimb of the Montagna dei Fiori Anticline. This fold is the outermost exposed contractional structure within the Pliocene–Quaternary antiformal stack of the outer Central Apennines. The integration of stratigraphic and structural data collected during a field geological survey enabled us to reconstruct a multiphase reactivation and deformation along the Montagna dei Fiori Fault. From the novel field data, a different interpretation for the evolution of the Montagna dei Fiori Fault is proposed. The fault originated as a Late Cretaceous – middle Miocene, NE-dipping, Dinaric up-thrust and was later reactivated, displaced and rotated during Pliocene Apennine thrusting and related folding, until assuming a present-day SW-dipping attitude with an apparent normal fault character. This newly proposed Dinaric origin of the Montagna dei Fiori structure is compared with an analogous subsurface example of a Palaeogene–Quaternary structure imaged by seismic reflection profile in the Adriatic foreland. The outcome of this combined field and subsurface investigation provides new elements to unravel the complex evolution of the Apennine thrust belt that developed at the expense of a previously deformed foreland, ahead of the advancing Dinaric chain.

The eclogite-facies Monviso meta-ophiolite Complex in the Western Alps represents a well-preserved fragment of oceanic lithosphere and related Upper Jurassic – Lower Cretaceous sedimentary covers. This meta-ophiolite sequence records the evolution of an oceanic core complex formed by mantle exhumation along an intra-oceanic detachment fault (the Baracun Shear Zone), related to the opening of the Ligurian–Piedmont oceanic basin (Alpine Tethys). On the basis of detailed geological mapping, and structural, stratigraphic and petrological observations, we propose a new interpretation for the tectonostratigraphic architecture of the Monviso meta-ophiolite Complex, and discuss the role played by structural inheritance in its formation. We document that subduction- and exhumation-related Alpine tectonics were strongly influenced by the inherited Jurassic intra-oceanic tectonosedimentary physiography. The latter, although strongly deformed during a major Alpine stage of non-cylindrical W-verging folding and faulting along exhumation-related Alpine shear zones (i.e. the Granero–Casteldelfino and Villanova–Armoine shear zones), was not completely dismembered into different tectonic units or subduction-related mélanges as suggested in previous interpretations. The present-day architecture of the Monviso meta-ophiolite Complex results from nappe-scale folding with a significant component of shearing, and strain partitioning of the Alpine deformation, which were controlled by the inherited occurrence of (i) lateral and vertical variations of facies and thickness of sediments, (ii) an intra-oceanic fault-rock assemblage, which acted as weak horizons in concentrating deformation, and (iii) remnants of a volcanic ridge, which consists of massive metabasalt. Thus, the recognition of pre-collisional, intra-oceanic, tectonostratigraphic inheritance represents an important step in reconstructing the tectonic evolution of meta-ophiolite units in orogenic belts.

The Sierras Pampeanas consist of basement uplifts that are mainly controlled by W-verging crustal thrusts. One of these, the Sierra Pie de Palo, is controlled by a blind thrust whose kinematics is debated. We analysed the reverse faults located along the eastern side of the range and show that these are characterized by small displacements (few hundreds of metres) of the Neogene and Quaternary deposits controlled by the inherited basement metamorphic foliation and shear zones. At the sierra scale, the inherited foliation pattern appears already folded, before the Cenozoic shortening, forming a series of antiforms and synforms with various wavelengths. We propose that this structure is amplified during the Plio-Quaternary shortening, resulting in a large asymmetrical basement-cored anticline where foliation-parallel slip can act as folding mechanism. The overall kinematics is consistent with an E-verging fault-propagation fold; this proposed kinematics is an alternative to the frequently suggested W-verging fault-bend fold model. Finally, we propose a new, alternative and speculative crustal and lithospheric structure for this region consisting of two E-verging basement thrusts coeval to W-verging Pampean thrusts, both rooting below the Precordillera, above an eclogitized lower crust.

We have conducted a structural study of both the basement-involved Malargüe fold-and-thrust belt (MFTB) and the active San Rafael Block (SRB), which are located in the Central Andes at latitude 34–36°S. Based on several field examples located both in the inner and frontal part of belt and from the distal foreland zone, we focus on the relationships between basement and cover deformation with respect to the known palaeogeography and structural inheritance. In several zones, we point out similarities in the structural and sedimentary responses to Andean shortening. The recent morphologic response has also been investigated through the analysis of active deformation along the eastern border of the SRB. We show that these structural and sedimentary processes are continuous in time and space since they can be applied in the various parts of the fold belt and also at different stages of fold-and-thrust-belt building as well. Finally, we propose the illustration of those mechanisms by complete cross-section along the Rio Grande valley and a possible kinematic scenario of deformation propagation.