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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]

Fold-and-thrust belts are characterized by the occurrence of foreland-verging thrusts and antithetic backthrust, which develop in the hangingwall of thrust sheets. Both thrust and backthrust bound the so-called pop-up structure, which is a deformed zone characterized by thrust- and backthrust-related anticlines. Pop-up structures mainly develop in fold-and-thrust belts characterized by a multilayered sedimentary sequence, consisting of limestones, marls, and shales, deformed above a weak décollement, such as evaporites. However, in this work, we combine field mapping, stratigraphic constrains, and structural analysis with 2D kinematic forward modeling to document a pop-up structure developed within limestones/dolostones, deformed above a strong décollement consisting of dolostones, in the central Apennines, Italy. In particular, we describe a SW-verging anticline and a NE-verging anticline in the SW and NE margin of the Serra Lunga ridge, respectively. Such folds were generated by a NE-dipping backthrust and by SW-dipping forethrust, respectively. Therefore, we suggest that the Serra Lunga ridge represents a pop-up structure, showing geometries similar to other pop-up structures observed within fold-and-thrust belts characterized by a multilayered sedimentary sequence. In addition, backlimb tilting of backthrust-related anticlines generates the forelandward-dipping monoclines, observed within thrust sheets in the Central Apennines and in several fold-and-thrust belts worldwide. • Field mapping highlights the deep structure of an internal sector of the central Apennines fold-and-thrust belt. • Pop-up structure in the central Apennines was generated by a NE-dipping backthrust and by a SW-dipping forethrust. • Backthrust generated a forelandward-dipping monocline, which characterize carbonate ridges in the central Apennines. [ABSTRACT FROM AUTHOR]

This paper presents the results of a geological mapping project across the northern portion of the Simbruini Mts. (Latium-Abruzzi Domain – Central Apennines), where a thick Cretaceous and Miocene carbonate succession, followed by a thick upper Miocene terrigenous foredeep succession, is exposed. The terrigenous succession also includes a peculiar lithoclastic unit (‘brecce della Renga fm.’), whose sedimentation is linked to pre-orogenic (Tortonian-Messinian) extensional tectonics. The study area experienced late Messinian-early Pliocene compression, which is the Apennine chain building phase, followed by Quaternary post-orogenic extension, related to the opening of the Tyrrhenian basin. A geological map, at 1:20,000 scale, illustrates the main stratigraphic and structural features of the area. [ABSTRACT FROM AUTHOR]

Abstract: The so-called Umbria–Marche Domain of Northern Apennines represents a vast depositional system, also stretching across the Adriatic Sea subsurface, that was characterized by dominantly pelagic sedimentation through most of its Jurassic to Oligocene/Early Miocene history. The pelagic succession is underlain by Hettangian shallow-water carbonates (Calcare Massiccio Fm.), constituting a regional carbonate platform that was subjected to tectonic extension due to rifting of the Adria/African Plate in the earliest Jurassic. While tectonic subsidence of the hangingwalls drove the drowning of the platform around the Hettangian/Sinemurian boundary, the production of benthic carbonate on footwall blocks continued parallel to faulting, through a sequence of facies that was abruptly terminated by drowning and development of condensed pelagites in the early Pliensbachian. By then rifting had ceased, so that the Pliensbachian to Early Cretaceous hangingwall deposits represent a post-rift basin–fill succession onlapping the tectonically-generated escarpment margins of the highs. During the early phases of syndepositional faulting, the carbonate factories of footwall blocks were still temporarily able to fill part of the accommodation space produced by the normal faults by prograding into the incipient basins. In this paper we describe for the first time a relatively low-angle (<10°) clinoform bed package documenting such an ephemeral phase of lateral growth of a carbonate factory. The clinoforms are sigmoidal, and form low-relief (maximum 5–7m) bodies representing a shallow-water slope that was productive due to development of a Lithocodium-dominated factory. Continued faulting and hangingwall subsidence then decoupled the slope from the platform top, halting the growth of clinoforms and causing the platform margin to switch from accretionary to bypass mode as the pre-rift substrate became exposed along a submarine fault escarpment. The downfaulted clinoform slope was then buried by base-of-escarpment proximal turbidites, forming a bypass wedge. Such a contact would be imaged along a seismic section as an unconformity, suggestive of shut-off of the local carbonate factory and onlap by pelagic mud. The composition of the turbidites, however, at least initially duplicates that of the clinoforms, indicating that the footwall top was still productive, yet the mechanisms of sediment shedding into the basin had changed due to the modifications of submarine topography induced by synsedimentary tectonics. [Copyright &y& Elsevier]

The microscale mechanisms of hydrocarbons movement along faults and fault zones, the potential carriers of hydrocarbons toward the productive geological traps, remain largely unknown. The majority of previous studies inferred the hydraulic behavior of faults with respect to hydrocarbon movements without providing meso and microstructural observations from faults permeated by hydrocarbons. To fill this gap, we document meso-structures together with the first fossil microstructural portraits of hydrocarbon flow and pathways along two hydrocarbon-bearing carbonate-hosted normal faults exposed in the central Apennines, Italy. In particular, we show that hydrocarbons cyclically move within tectonically active carbonate normal faults possibly during interseismic and coseismic phases of the seismic cycle. Channelized structures, injection features, and clast-cortex grains suggest the occurrence of transient and localized pulses of pressurized hydrocarbons during coseismic slip. In particular, clast-cortex grains are very similar to microstructures that develop along fault planes for slip velocities between 0.0001 and 1 m/s. Patches of hydrocarbon-bearing breccias/cataclasites with lobate and irregular boundaries, crackle breccias filled by hydrocarbons, and hydrocarbons arrested against hydrocarbon-free discrete fault planes suggest hydrocarbon flow during the interseismic phases with hydrocarbon (over)pressure dissipation after coseismic phases. Fault permeability is created during the coseismic phase and hydrocarbons penetrate the most permeable and uncemented uncohesive fault rocks within the damage zone and arrest against and/or within low-permeability and cemented fault cores. Results are consistent with previous numerical simulations on hydrocarbon movements along faults and time-lapse seismic-reflection imaging, suggesting that the movement of hydrocarbon occurs during interseismic periods within tectonically active faults and along permeable zones cyclically created by seismic activity. Results from this paper are crucial for modelling the hydraulic behavior of carbonate fault damage zone, which have progressively gained popularity as targets of hydrocarbon exploration and production and for CO 2 or H storage. • Hydrocarbon movement along carbonate normal fault is strongly heterogeneous. • Hydrocarbons permeate fault rocks based on local permeability. • Hydrocarbons move during coseismic and interseismic phases. • Transient and local pressurized hydrocarbons can occur during the coseismic phase. [ABSTRACT FROM AUTHOR]

The reconstruction of the hydrocarbon migration and entrapment history is fundamental for reducing risks and identifying traps and migration pathways during oil exploration and exploitation in fold-and-thrust belts, which host 14% of the world's discovered oil reserves. Within fold-and thrust belts, faults and folds have fundamental roles in controlling hydrocarbon migration, entrapment, and/or leakage. Past studies have mainly focused on the role of syn-orogenic thrusts, tear faults, and folds in controlling hydrocarbon migration and entrapment. On the contrary, little attention has been dedicated to the role of normal faults in hydrocarbon remobilization during the post-orogenic extension. We combine field and subsurface data with geological evidence from the Ripi oil field, central Apennines (Italy), and propose a conceptual model for hydrocarbon remobilization along post-orogenic normal faults and potential entrapment within shallow reservoirs. Results show that post-orogenic normal faults promoted up-dip hydrocarbon remobilization from oil traps generated during fold-and-thrust belt development. Where pre-orogenic deposits are still covered by syn-orogenic deposits, hydrocarbons moved up-dip along post-orogenic normal faults and impregnated high-porosity sandstone lenses, generating discontinuous and heavy oil reservoirs. On the contrary, where syn-orogenic deposits were eroded in response to orogenic uplift, hydrocarbons leaked at the Earth's surface. Results from this study can be applied to reduce risks during hydrocarbon exploration and appraisal in similar tectonic settings, such as Hellenides and Carpathian fold-and-thrust belts, as well as the southern Apennines of Italy, where the Tempa Rossa and Monte Alpi oil fields, two of the largest onshore oil fields in Western Europe, were discovered in the last decades. [Display omitted] • Post-orogenic extension controlled hydrocarbon remobilization from deep traps. • Hydrocarbons migrated up-dip along post-orogenic normal faults. • Remobilized hydrocarbons entrapped into high-porosity sandstones. • Where seal was eroded, hydrocarbons leaked to the Earth's surface. • Heavy oil is expected in reservoirs charged by post-orogenic normal faults. [ABSTRACT FROM AUTHOR]