The study aims to define a possible evolutionary geomorphological model of small catchments (i.e., <40 km2) that characterise the clayey hilly landscape of Central Apennines and Northern Sicily ...piedmont for the late Pleistocene–Holocene (i.e., the last 20,000 years, from the last glacial stage to the Holocene climate amelioration). The study is based on an integrated approach incorporating (i) geomorphological surveys and mapping, (ii) dating of Quaternary continental deposits, and (iii) topographical and morphometrical processing. It combines the data collected from previous published investigations as well as new data, specifically related to the availability of geo-chronological markers, and helps outline a common evolutionary model. The selected small catchments are tributaries of major rivers in inland areas (small catchments of the inland hills of Tuscany, Marche, and Sicily) or flow directly to the coast (coastal small catchments in Abruzzo). For each area, the geomorphological features (clay dominated bedrock, erosional landforms and fluvial terraces, and erosional/depositional strath terraces) and the dating of Quaternary deposits (from <50kyr to 15kyr) were compared, reconstructing the morphometry of the probable late Pleistocene landscape configuration. The analysis of the results showed that, although currently characterised by different climatic and geo-structural conditions, the different basins underwent a common geomorphological evolution mostly since the late Pleistocene. During the last glacial stage, under cold climate rhexistasy conditions, the small catchments were dominated by low gradient erosional surfaces with the deposition of fluvial, colluvial, or slope deposits, resulting in the formation of uniform slopes and wide minor valleys. The Holocene climate warming, together with marine transgression and tectonic uplift, induced the incision and dissection of the erosional surfaces and the continental deposits via gravitational movements and rapid erosion processes up until the present-day landscape configuration. The control factors of this evolution are most likely linked to the climate changes at the beginning of the Holocene and the interplay with the changes in the local base level of the small catchments since the late Pleistocene, combining late Quaternary tectonic uplift, sea-level rise, and river/coastal incision.
•New insights from inland-coastal small catchments of Central Italy and Northern Sicily•Common evolution model for clayey small catchments since the Late Pleistocene•Local base level changes have controlled small catchments evolution.•Interplay of climate, eustatism and tectonics has driven clayey landscape incision.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
We address the modeling of spatial distribution of coseismic landslides, based on an empirical approach applied to both recent and historical well-documented events. We analyze a dataset of 11 ...historical and recent normal faulting earthquakes in the Italian Central Apennines. Firstly, making use of a kernel density estimator approach, we calculated the regression between the extent of the maximum area affected by landslides (A; km
2
) and Mw, on the combined dataset of recent and historic earthquakes: Log A = (1.0397 Mw)–3.9288. Then, for recent earthquakes only, we analyzed the attenuation regression of landslide density (Dens; no. of landslides/km
2
) with distance from surface fault trace (Dfault; meters): Dens = 0.3661 × exp (− 5.053 Dfault). Historical events, still presenting systematically lower values of landslide densities, can be regressed on the same functional form resulting in a similar factor of attenuation with distance but with a different scaling factor. We thus argue that empirical regressions on historical earthquake-triggered landslides can be successfully exported elsewhere if a well-documented catalog is present and a calibration with several recent events can be done.
During the last decades, central Italy has been struck by severe seismic sequences. Some authors have suggested that inherited thrust faults may have played an important role in controlling the ...recent-to active extensional deformation in the area, particularly during the 2016 Central Italy seismic sequence. To explore this hypothesis, we performed an analogue modelling study that addressed the structural evolution of a composite, heterogeneous multilayer affected by polyphase deformation. The overall three-dimensional geometry resulting from the modelling consists of a flat-ramp extensional fault system, with flats being localised along the weaker stratigraphic units, and ramps locally reactivating the pre-existing thrust ramps at depth. At shallower levels, deformation can localize at newly-formed short-cut faults depending on the geometry of deeper structures. The experimental results provide further support to the hypothesis of a link between Quaternary normal faults and inherited thrust faults during the 2016 seismic sequences. Specifically, analogue modelling results suggest that the Quaternary fault pattern may be controlled by the interaction between the active stress field and the pre-existing compressional structures. This scenario bears significant implications regarding the empirical relationship between the geometry of surface faulting and the magnitude of earthquakes, with considerable repercussions on seismic risk assessment.
•Analogue models are applied to the 2016 seismic sequences in central Italy.•Connection between Quaternary normal faults and thrust faults is proposed.•Active extensional system show a flat-ramp geometry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
The Southern Italy orogen preserves deep-marine turbitic clastic wedges that record the key tectonic events during structural growing over the Adria margin. The regional tectonic transition from ...thick-skinned Calabrian accretion and deformation (during Late Paleogene-to-middle Miocene) to thin-skinned Southern Apennines thrusting (since early-middle Miocene) is recorded by diverse contrasting petrofacies in uppermost Paleogene and Miocene sandstones of dominantly turbiditie deposits. Most of these sandstones reflect in time quartzolithic and quartzofeldspathic and arkosic petrofacies derived from growing and unroofing Calabrian terranes. Quartzose petrofacies mainly indicate provenance from cratonal African margin, during Langhian, and/or from lowland internal domains before its deformation, during the Cretaceous to Paleogene. Volcaniclastic sandstone petrofacies also testify active volcanism during the Late Paleogene to early Miocene. These variable compositions indicate strong palaeogeographic constraints for the central-western Mediterranean, during the Neogene, reflecting provenance relationships from differentiate source rocks. These include interplays between ophiolitiferous, uplifted continental shallow to deep crust terranes, volcanic and sedimentary (mostly carbonate) source rocks. Sandstone detrital modes provide an example of the close relations between clastic compositions and growing orogen in southern Italy and may contribute to unravel the geodynamic history of other major orogens.
•We examine Cenozoic sediments of the southern Italy.•Stratigraphic relations and compositional signatures are used.•We study the sedimentary evolution of the southern Italy foreland region.•Relations from sandstone petrofacies to tectonic evolution of southern Italy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
This paper furnishes a brief, but exhaustive, description of the tectonics and stratigraphy of the Campania region (southern Italy). The attached geological map (Main Map) at 1:250,000 scale should ...be considered as a first attempt to provide a more detailed geological cartography of the entire region, with respect to the available literature, in the light of scientific advances in stratigraphy and tectonics reached in the last years. The geological setting, proposed in this study, is the result of a review and reinterpretation of the current geological knowledge plus original surveys carried out in some key sectors of the area. We also include a schematic stratigraphic chart and three geological cross-sections illustrating the tectonic architecture in depth for the internal and external zones. The geodatabase was compiled in GIS format and subsequently imported in vector graphic software to allow a classical cartographic design.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The Viggiano Mt. platform carbonates form a layered succession cross-cut by a dense array of pressure solution seams, and five sets of fractures and veins, which together form a sub-seismic ...structural network associated with polyphasic tectonic evolution. To assess the influence exerted by depositional and diagenetic heterogeneities on fracture geometry, distribution and multiscale properties, we present the results of stratigraphic, petrographic, mineralogical and mesoscale structural analyses conducted at the Viggiano Mountain, southern Italy. Based on rock textures and fossil associations, we documented that the Sinemurian–Pleinsbachian carbonates were deposited in a low-energy open lagoon, the Toarcian carbonates in a ramp setting rimmed by sand shoals, and the Cenomanian carbonates in a medium- to high-energy, lagoonal–tidal setting. Fracture-density (P20) and intensity (P21) values computed after circular scanline measurements show similar trends in both Sinemurian–Pleinsbachian and Toarcian carbonates, consistent with the bed and bed-package heterogeneities acting as efficient mechanical interfaces during incipient faulting. On the other hand, P20 and P21 do not show very similar variations throughout the Cenomanian carbonates due to pronounced bed amalgamation. Throughout the study area, the aforementioned parameters do not vary in proportion to the bed thickness, and show higher values within the coarse-grained carbonate beds. This conclusion is confirmed by results of linear scanline measurements, which focus on the P10 properties of the most common diffuse fracture set. The original results reported in this work are consistent with burial-related, physical–chemical compaction and cementation processes affecting the fracture stratigraphy of the Mesozoic platform carbonates.
Tectonic activity in convergent plate boundaries commonly involves backward migration (rollback) of narrow subducting slabs and segmentation of subduction zones through slab tearing. Here we ...investigate this process in the Italian region by integrating seismic tomography data with spatiotemporal analysis of magmatic rocks and kinematic reconstructions. Seismic tomography results show gaps within the subducting lithosphere, which are interpreted as deep (100–500 km) subvertical tear faults. The development of such tear faults is consistent with proposed kinematic reconstructions, in which different rates of subduction rollback affected different parts of the subduction zone. We further suggest a possible link between the development of tear faults and the occurrence of regional magmatic activity with transitional geochemical signatures between arc type and OIB type, associated with slab tearing and slab breakoff. We conclude that lithospheric‐scale tear faults play a fundamental role in the destruction of subduction zones. As such, they should be incorporated into reconstructions of ancient convergent margins, where tear faults are possibly represented by continental lineaments linked with magmatism and mineralization.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Sediment connectivity within a catchment depends largely on the morphological complexity of the catchment and is strictly related to the anthropogenic modification of the landscape.
In this context, ...the present research evaluates the role of anthropogenic effects on landscape modifications and the resulting influence on sediment delivery. An assessment of sediment connectivity was carried out for three different human impact scenarios: (i) drainage system density reduction, (ii) road network variation and (iii) land use changes. In addition, shallow landslides were used as sediment source areas to evaluate the potential connection between these sediment sources and downstream areas (e.g. main channels and road network).
Two small catchments in the Oltrepò Pavese area (Northern Apennines, Italy), with different size and morphological setting, were analysed: the Rio Frate (1.9km2) and the Versa (38km2) catchments. In both areas, several shallow landslides were triggered in 2009 (Rio Frate and Versa) and in 2013 (Versa).
Results highlight the role of the landscape complexity in coupling/decoupling upstream sediment sources, such as shallow landslides, from the main channel network and roads.
In addition, the analysis identified instability phenomena characterized by high connectivity values, allowing determination of the areas in which mobilized sediment could potentially damage important infrastructures such as the road network or contribute to flooding induced by aggradation or obstruction of the river bed.
The proposed approach provides a methodological framework to help improve watershed and land management strategies, especially in shallow landslides prone-areas.
•Anthropogenic effects on sediment connectivity of shallow landslides•Geomorphometric characterization of slope instability phenomena•Three scenarios representative of landscape modifications were evaluated.•Degree of connectivity between shallow landslides and channels network and roads•Instability phenomena characterized by the highest connectivity were identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
The present study focuses on the petrographic and petrological characteristics of mantle bodies included in Upper Cretaceous sedimentary melanges of the External Ligurian units (Northern Appennine), ...within the Monte Gavi and Monte Sant'Agostino areas. Two distinct pyroxenite-bearing mantle sections were recognized, mostly based on their plagioclase-facies evolution. The Monte Gavi mantle section is nearly undeformed and records a process of melt infiltration and reaction under plagioclase-facies conditions. The melt-rock interaction event involved both peridotites (mostly harzburgites) and enclosed spinel pyroxenite layers, and is estimated to have occurred at 0.7–0.8 GPa. In the Monte Gavi peridotites and pyroxenites, the spinel-facies clinopyroxene was partially replaced by plagioclase and new orthopyroxene (± secondary clinopyroxene). The reactive melt migration led to relatively high TiO2 contents in relict clinopyroxene and spinel (up to 2.3 wt% and 1.0 wt%, respectively, in the pyroxenites), with the latter also having high Cr# (up to 35 in the peridotites). The Monte Sant'Agostino mantle section displays a widespread ductile shearing and no evidence for melt-rock interaction under plagioclase-facies conditions. The main deformation phase recorded by the Monte Sant'Agostino peridotites (mostly lherzolites) is estimated to have occurred at 750–780 °C and 0.3–0.6 GPa, and gave rise to protomylonitic to ultramylonitic textures characterized by 10–50 μm neoblasts. The enclosed pyroxenite layers yielded relatively high temperature and pressure estimates (870–930 °C and 0.8–0.9 GPa). Presumably, in the Monte Sant'Agostino mantle section, plagioclase crystallization occurred earlier in the pyroxenites than in enclosing lherzolites, thereby enhancing strain localization and formation of mylonite shear zones in the entire mantle section. We propose that subcontinental mantle section from the External Ligurian units consists of three distinct mantle domains, developed in response to the rifting evolution that ultimately formed a Middle Jurassic ocean-continent transition: (1) a spinel tectonite domain that underwent no significant deformation and melt-rock reaction under plagioclase-facies conditions, characterized by static plagioclase development, (2) a plagioclase mylonite domain experiencing melt-absent deformation, and (3) a nearly undeformed domain that underwent melt infiltration and reaction under plagioclase-facies conditions. We relate mantle domains (1,2) to a rifting-driven uplift in the late Triassic accommodated by large-scale shear zones consisting of plagioclase mylonites.
•Rifting evolution of two distinct peridotite-pyroxenite mantle sequences•Thermobarometry of plagioclase-facies mantle rocks•Reactive melt migration under plagioclase-facies conditions•Melt-absent ductile shearing and mylonite-ultramylonite formation•New constraints on the mantle evolution in the Western Tethys OCT
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
The Cilento Group (Langhian-to-Tortonian) is a thick turbiditic succession of the Southern Apennines foreland region that unconformably overlain the Lucanian oceanic terranes. The San Mauro Formation ...(SMF) form the uppermost portions of the Cilento Group, and consists of 1400–1600 m thick turbiditic succession including quartzolithic, volcanolithic, and quartzofeldspathic sandstones with several carbonatoclastic layers interbedded, passing upward from distal-to proximal-facies associations. Here, based on the vertical changes of texture and petrology in the succession, the SMF was divided in two main sections. The key depositional features and the main post-depositional processes, of lower- and upper-part of SMF, are compared with the most significant petrophysical properties with the purpose to elucidate the major controls on the porosity and permeability evolution during burial. With this aim, fifty-four thin sections were petrographically investigated, while mercury intrusion analysis was performed on twenty-four samples. Compaction, cementation, dissolution and fracturing occurred in the SMF, altering porosity and permeability. The main authigenic minerals are: 1) carbonates, mainly calcite and less dolomite, dominantly occurring as replacement of framework grains; 2) Phyllosilicates, mainly developing in the upper part of SMF as pore-filling cement or as small and incomplete grain coatings; 3) Fe-oxides occurring as coatings or localized crystals. The relationship between the compactional porosity loss (COPL) and the cementational porosity loss (CEPL) testifies the primary role of compaction in decreasing porosity, reducing the intergranular volume (IGV) to 11.1% in the lower SMF and to 16.7 % in the upper SMF. The coarse upper SMF samples exhibit lower mean porosity and permeability (6 % and 215 mD, respectively) than the fine lower SMF samples (9.2 % and 774.2 mD, respectively). In the upper section of SMF, a comparatively more widespread pore-filling cementation and the abundant detrital matrix affect depositional intergranular porosity, reducing the pore size and interconnectivity. Moreover, the higher amount of rigid grains (petrofacies dependent) and their brittle deformation produce an intricate fragmentation and micro-fracturing system, altering pores geometry and affecting permeability. On the contrary in the lower SMF, ductile components suffer compaction more than rigid ones, leading the lowest IGV. In addition, a higher volume of authigenic carbonates occur as replacement on framework components, hence playing a minor occluding role and less affecting the pore system. Composition and tectonics rule the effects of diagenetic processes in the San Mauro turbiditic succession, following the vertical evolution of depositional facies association and petrology.
•The primary diagenetic events reflect the detrital mode and depositional assemblages of the San Mauro turbiditic sequence.•In San Mauro Formation sandstones, compaction is the main diagenetic process in reducing original porosity.•Authigenic carbonates and clay minerals are the main diagenetic products.•The key petrophysical properties evolution depends from both the framework composition and depositional facies association.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
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