No abstract

Arcuate fold-and-thrust belts have been extensively studied in the literature. Less attention, however, has been paid to the characteristics of local-scale arcuate structures, meaning 5–10 km long fold or thrust traces that display map-view curvature. Nevertheless, detailed investigation of small arcuate structures hosted in major arcs can contribute to understanding the pervasiveness of deformation mechanisms. We performed a combined geological and palaeomagnetic study on 21 sites from a c. 60 km2 area in the Northern Apennines in order to analyse minor arcs at a kilometric scale. As evidenced by the geological and structural analysis performed on the 21 sites, the fold axial trend changes from N–S to NW–SE in the study area. The comparison with palaeomagnetic results shows the lack of correlation between vertical axis rotations and fold axial trends. As a consequence, the minor arcuate shapes of thrusts and related folds are interpreted as mostly primary features inherited from the geometry of the palaeomargin, represented by pre-orogenic faults, according to a context of inversion tectonics.

<p>The tectonic evolution of the Mediterranean is well studied, but the models often cover a limited period of geological time and are not always placed in a wider context. Its evolution is linked to the surrounding African and Eurasian continents and their relative movements.</p> <p>A new fully deformable tectonic model of the Mediterranean has been created as part of a proprietary plate model. This work has led to the identification of key global tectonic events influencing the development of the Mediterranean from the Early Permian to the present day. This first fully-deformable plate model of the Mediterranean enables to account for the shortening and extension that occurred in the area at a temporal resolution of 1 Ma. In most available plate models, plates are rigidly rotated back to their paleo-position, meaning they preserve their present-day size and shape. In some recent papers, the extent of deformation has been illustrated for selected time-slices, but these models cannot be considered to be ‘deformable’ because the deformation is not modelled in a continuous manner.</p> <p>Following Hercynian orogenesis and until the break-up of Pangea, the Mediterranean was dominated by extensional tectonics along its southern margin, as a series small continental blocks rifted from the northern margin of Gondwana. The opening of the Central Atlantic in the Late Triassic-Early Jurassic led to displacement between Eurasia and Africa south of Iberia and the development of the Alpine Tethys, as the Atlantic initially propagated northwards to the east of Iberia. Rotation of Africa caused by the opening of the South Atlantic in the Late Jurassic-Early Cretaceous led to a ‘jump’ in spreading to the west, at the Iberia-Newfoundland margin. These larger scale plate motions overprinted the more local impacts of continued extension along the northern margin of Africa (e.g. Pindos Ocean). Opening of the North Atlantic once again changed the relative motion of Eurasia and Africa, and initiated a period of oceanic subduction and collision that culminated in the Alpine orogeny. Crucial to this story is the paleo-position of Apulia/Adria, which remained attached to Africa and was able to act as an indenter into Eurasia during the Alpine compression. Evidence for this connection will be presented and discussed.</p> <p> </p> <p> </p>