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During the sampling of a stratigraphic section along the shore of the Fiastra Lake (Carg Project - Sheet 313 “Camerino” of the Geological Map of Italy at 1:50 000 scale), a small rock boulder with partially exposed bony material was discovered at the base of a small cliff at the northern termination of the Sibillini Mts. In this area, the classical facies of Umbria-Marche stratigraphic succession are well-exposed. The Oligocene-Miocene portion of the succession is represented by the ~200 m-thick Scaglia Cinerea Formation, passing upwards to the ~100 m-thick Bisciaro Formation. The microfossil assemblage has allowed the specimen to be constrained to the lower Burdigalian. The skeletal remains were examined using a CT-SCAN, a non-invasive method that has proven to be highly performing. The analysis revealed some articulated vertebrae, deformed by lithostatic compaction, which are attributed to a shark of the order Lamniformes. Subsequently, the vertebrae were digitally isolated, extracted from the surrounding matrix, and rendered into three-dimensional prints. Through digital retro-deformation, the body length of the lamniform shark was estimated to be approximately 4 metres. Further considerations on the vertebrae allowed us to infer that the studied shark had similarities to either Isurus oxyrinchus Rafinesque, 1810 or Carcharodon carcharias Linnaeus, 1758. The development of a dead-fall microbial community likely facilitated the preservation of the vertebrae. The studied specimen represents the first occurrence of a lamniform shark in the Lower Miocene of the Umbria-Marche Domain and represents one of the very rare recorded occurrences of lamniforms from the Lower Miocene of Italy [ABSTRACT FROM AUTHOR]

The central Apennines are a fold-thrust belt currently affected by post-orogenic extensional seismicity. To constrain the influence that the inherited thrust-related structures exert on the present seismic behavior of the belt, we provide the high-resolution structural and hydraulic characterization of one of the most external exposed thrust fault systems of the central Apennines, the Sibillini Mts. Thrust Front (STF). We integrate structural mapping, multiscale structural analysis, and in situ air permeability on the brittle structural facies of the thrust zone. We also performed K-Ar dating of selected fault rocks to better constrain structural inheritance. The STF is defined by a complex, ~300-m-thick deformation zone involving Meso-Cenozoic marl and limestone that results from the accommodation of both seismic and aseismic slip during shortening. Permeability measurements indicate that the low permeability (10-2 ÷ 10-3 D) of the marly rich host rock diminishes within the thrust zone, where the principal slip surfaces and associated S-C structures represent efficient hydraulic barriers (permeability down to ~3 x 10-10 D) to sub-vertical fluid flow. Field data and K-Ar dating indicate that the STF began its evolution ca. 7 Ma (early Messinian). We suggest that the studied thrust zone may represent a barrier for the upward migration of deep fluids at the hypocentral depth of present-day extensional earthquakes. We also speculate on the influence that similar deformation zones may have at depth on the overall regional seismotectonic pattern by causing transient fluid overpressures and, possibly, triggering cyclic extensional earthquakes on normal faults prone to slip while crosscutting the earlier thrust zones (as per a classic fault valve behavior). This mechanism may have controlled the origin of the 2016-2017 central Apennines devastating earthquakes. [ABSTRACT FROM AUTHOR]

"Classic" field mapping in sedimentary successions, where lithostratigraphy, biostratigraphy and sedimentology meet, still has potential for producing answers to long‐standing problems in basin analysis. In the Northern Apennines of Italy, constraints on the slip rates of Early Jurassic rift faults, related to the embryonic separation of Eurasia and Gondwana, are provided by sedimentology and ammonite biostratigraphy, coupled with the field mapping of exposed tracts of the submarine escarpments and of the clinoform slopes which bordered carbonate footwall blocks. Slip rates of 600–1,000 m/Myr are here computed for Tethyan rift faults, producing >1 km of palaeostructural relief in ~2 million years (earliest Sinemurian: Bucklandi p.p. – Semicostatum p.p. zones). [ABSTRACT FROM AUTHOR]

The Mt Nerone area hosts a Jurassic-Cretaceous Pelagic Carbonate Platform (PCP)-basin succession in the Umbria-Marche Domain (Central Italy). Despite being studied thoroughly on sedimentological and geological aspects, wide-spectrum palaeocological studies are currently missing for this peculiar setting. While several studies on the invertebrate fauna of PCP system are available, the vertebrate fauna remained for a long time mostly unknown. Recently a renewed interest has been directed to vertebrate remains of the region. To date, an articulated dentition and some other tooth fragments of hybodont sharks and neoginglymodian actinopterygians have been described from the Jurassic of the Mt Nerone area. These taxa indicate the existence of diverse durophagous ecological niches available for durophagous fauna in the PCP system, linked to the abundant hard-shelled invertebrate fauna inhabiting the structural highs. In the present contribution we report and describe remains of neoselachians Synechodontiformes from five localities of the Mt Nerone area. The new material, represented by several isolated teeth and referred to as Sphenodus spp., testifies an additional trophic level for the Jurassic palaeoecology in the Umbria-Marche Domain, throwing new light on the peculiar PCP-basin ecosystem. [ABSTRACT FROM AUTHOR]