The northern Apennines of Italy are a classical site for studying fundamental issues in tectonic studies, such as ophiolite formation and emplacement, kinematics of thrust wedges, role of in‐sequence and out‐of‐sequence thrusting, and of along strike segmentation, synorogenic versus postorogenic extension, and interplay between tectonics, erosion, and sedimentation. Accordingly, the northern Apennines have been extensively studied since more than two centuries ago. Despite the huge amount of available data with different resolution, a 3‐D comprehensive regional view combining in a modern framework all available surface and subsurface information for contiguous sectors of the chain is still lacking. We performed such an attempt in the area framed between the Taro valley to the north and the northern termination of the Alpi Apuane to the south. The region includes the main morphostructural zones of the north‐west Apennines from the Tyrrhenian coast (SSW of La Spezia), through the main topographic divide of the Apennines, up to the foothills range of the chain to the north. The area has been investigated through a multidisciplinary approach that integrated surface geological data, collected during the last two decades of structural and stratigraphic field works, and subsurface geological data. The construction of two regional NE‐SW trending cross sections (the Levanto‐Pontremoli‐Parma to the north and the La Spezia‐ Sarzana‐North Apuane‐Cerreto to the south), intersected by a NW‐SE trending Taro‐Lunigiana‐Alpi Apuane composite section, allowed us to illustrate (i) the role of out‐of‐sequence blind thrusting in the basement and (ii) the presence of low‐angle normal faulting and its relationships with recent to active high‐angle normal faulting. Both extensional and contractional systems have relevant implications for the tectonics of the northern Apennines as well as the seismotectonics of the studied region.

A revision of late Palaeozoic tectonics recorded in Tuscany, Calabria and Corsica is here presented. We propose that, in Tuscany, upper Carboniferous-Permian shallow-marine to continental sedimentary basins, characterized by unconformities and abrupt changes in sedimentary facies, coal-measures, red fanglomerate deposits and felsic magmatism, may be related with a transtensional setting where upper-crustal splay faults are linked with a mid-crustal shear zone. The remnants of the latter can be found in the deep-well logs of Pontremoli and Larderello-Travale in northern and southern Tuscany respectively. In Calabria (Sila, Serre and Aspromonte), a continuous pre-Mesozoic crustal section is exposed, where the lower-crustal portion mainly includes granulites and migmatitic paragneisses, together with subordinate marbles and metabasites. The mid-crustal section, up to 13 km-thick, includes granitoids, tonalitic to granitic in composition, emplaced between 306 and 295 Ma. They were progressively deformed during retrograde extensional shearing, with a final magmatic activity, between 295 ± 1 and 277 ± 1 Ma, when shallower dykes were emplaced in a transtensional regime. The section is completed by an upper crustal portion, mainly formed by a Palaeozoic sedimentary succession deformed as a low-grade fold and thrust belt, and locally overlaying medium-grade paragneiss units. As a whole, these features are reminiscent of the nappe zone domains of the Sardinia Variscan Orogen. In Corsica, besides the well-known effusive and intrusive Permian magmatism of the “Autochthonous” domain, the Alpine Santa Lucia Nappe exposes a kilometer-scale portion of the Permian lower to mid-crust, exhibiting many similarities to the Ivrea Zone. The distinct Mafic and Granitic complexes characterizing this crustal domain are juxtaposed through an oblique-slip shear zone named Santa Lucia Shear Zone. Structural and petrological data witness the interaction between magmatism, metamorphism and retrograde shearing during Permian, in a temperature range of c. 800–400 °C. We frame the outlined paleotectonic domains within a regional-scale, strain–partitioned, tectonic setting controlled by a first-order transcurrent/transtensional fault network that includes a westernmost fault (Santa Lucia Fault) and an easternmost one (East Tuscan Fault), with intervening crustal domains affected by extensional to transtensional deformation. As a whole, our revision allows new suggestions for a better understanding of the tectonic framework and evolution of the Central Mediterranean during the late Palaeozoic.

The last (decompression) stages of the metamorphic evolution can modify monazite microstructure and composition, making it difficult to link monazite dates with pressure and temperature conditions. Monazite and its breakdown products under fluid‐present conditions were studied in micaschist recovered from the cuttings of the Pontremoli1 well, Tuscany. Coronitic microstructures around monazite consist of concentric zones of apatite + Th‐silicate, allanite and epidote. The chemistry and microstructure of the monazite grains, which preserve a wide range of chemical dates ranging from Upper Carboniferous to Tertiary times, suggest that this mineral underwent a fluid‐mediated coupled dissolution–reprecipitation and crystallization processes. Consideration of the chemical zoning (major and selected trace elements) in garnet, its inclusion mineralogy (including xenotime), monazite breakdown products and phase diagram modelling allow the reaction history among accessory minerals to be linked with the reconstructed P–T evolution. The partial dissolution and replacement by rare earth element‐accessory minerals (apatite–allanite–epidote) occurred during a fluid‐present decompression at 510 ± 35 °C. These conditions represent the last stage of a metamorphic history consisting of a thermal metamorphic peak at 575 °C and 7 kbar, followed by the peak pressure stage occurring at 520 °C and 8 kbar. An anticlockwise P–T path or two clockwise P–T loops can fit the above P–T constraints. The former path may be related to a context of late Variscan strike‐slip‐dominated exhumation with minor Tertiary (Alpine‐related) reworking and fluid infiltration, while the latter requires an Oligocene–Miocene fluid‐present tectono‐metamorphic overprint on the Variscan paragenesis.

Based on mapping of laterally traceable stratigraphic discontinuities, we propose a high-resolution allostratigraphic scheme for one of the world’s foremost fossil marine vertebrate Lagerstätten: the lower Miocene strata of the Chilcatay Formation exposed along the Ica River near Zamaca, southern Peru. Measured sections combined with 1:10,000 scale mapping of a 24 km² area provide an overview of the stratal architecture, as well as a general facies framework and interpretation of the various depositional settings. As a whole, the Chilcatay alloformation is bounded by the CE0.1 unconformity at the base and the PE0.0 unconformity at the top. An internal Chilcatay surface, termed CE0.2, splits the alloformation into two distinct allomembers (Ct1 and Ct2). The Ct1 allomember comprises three facies associations recording deposition in shoreface, offshore, and subaqueous delta settings. The Ct2 allomember comprises two facies associations, recording deposition in shoreface and offshore settings. Using these data, we place the rich marine vertebrate assemblage in a precise spatial and stratigraphic framework. The well-diversified vertebrate assemblage is dominated by cetaceans (mostly odontocetes) and sharks (mostly lamniforms and carcharhiniforms); rays, bony fish, and turtles are also present. Taxonomic novelties include the first records of baleen whales, platanistids, and eurhinodelphinids from the Chilcatay Formation.