Papers by Domenico Ridente
Atlas of Bedforms in the Western Mediterranean, 2016
Submarine canyons along the Ionian Calabria margin indent large shelf sectors as the coalescing o... more Submarine canyons along the Ionian Calabria margin indent large shelf sectors as the coalescing of smaller failure scarps progresses under the control of tectonic deformation and high sedimentation rates, promoted by regional uplift and rejuvenation of the drainage basin. The Punta Alice Canyon and the Ciro Canyon show such complex canyon heads, almost completely eroding the shelf and thus affecting sediment pathways along and across strike. Wavy bedforms of variable shape and size are observed both outside and inside the two canyon systems, providing an indication of how sediment is sourced and transported. We analyse the distribution of bedforms in order to define how both open shelf currents and confined sediment fluxes contribute to their formation outside and inside canyons. We also remark on the importance of the orientation of canyon heads and channels relative to flow direction of currents, and of slope failure as a sediment source.
RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA
Hildoceras bifrons (Bruguière, 1789) is a cosmopolite ammonite species from the Lower Jurassic of... more Hildoceras bifrons (Bruguière, 1789) is a cosmopolite ammonite species from the Lower Jurassic of the Boreal and Mediterranean (Tethys) palaeogeographical provinces. Inter-demic and phylogenetic variability are noticeable, also affecting the most distinctive morphological trait: the spiral groove along the whorl flank. Since the XIX century, however, a number of morphotypes assigned to Hildoceras bifrons (many of which from the Apennines and other Italian localities) lacked a neat spiral groove, replaced by a shallow, variably evident and discontinuous inflection. Buckman (1918) provided a photographic illustration of a specimen he interpreted as corresponding to the holotype, until then represented by a drawing described by Lister (1678) as Ammonis cornu. Buckman’s illustration assessed the well-carved spiral groove as a distinctive feature of the holotype and a trademark of the species. Nevertheless, several authors insisted on referring faintly grooved specimens to Hildoceras bif...
Geosciences
The subfamily Leukadiellinae Macchioni and Venturi, 2000 includes the two rare genera Leukadiella... more The subfamily Leukadiellinae Macchioni and Venturi, 2000 includes the two rare genera Leukadiella Renz, 1913 and Renziceras Arkell, 1953. Genus Leukadiella is characterised by ornamental and structural features unusual to the family Hildoceratidae Hyatt, 1867; for this reason, it has been occasionally grouped with other “odd” representatives of this family, as, for instance, Frechiella Prinz, 1904 and Paroniceras Bonarelli, 1893. While Renziceras comprises only one species, the eleven species currently recognised within Leukadiella show a noticeably discontinuous variability field; together with rarity of findings, the interpretation of this variability represents a renowned obstacle to their classification and phylogenetic reconstruction. Following an analysis of the morphological characters commonly used for defining Leukadiella species, a revised taxonomic scheme is herein proposed. Two clusters of characters are defined, based on which two morphologically distinct groups of spec...
Journal of Mediterranean Earth Sciences, Oct 12, 2016
The record of Hildoceras species from the Rosso Ammonitico marls (Toarcian) near Terni (Central A... more The record of Hildoceras species from the Rosso Ammonitico marls (Toarcian) near Terni (Central Apennines) is analysed in order to outline a possible relationship between ontogenetic and phylogenetic variability. Bed by bed sampling provides evidence of ontogenetic variability in shell morphology that parallels evolutionary change, suggesting a possible control by heterochrony. Specifically, heterochrony is proposed as a potential mechanism by which: 1) discontinuous inflections accompanying rib fading at the inner flank of Hildoceras lusitanicum , initially a character of later growth stages, are progressively anticipated during ontogeny, finally culminating in the spiral groove of Hildoceras bifrons ; 2) delayed maturation and inhibition of the adult "uncoiling" stage of Hildoceras bifrons , concomitant to allometric growth of whorl height, result in the overall involute and relatively compressed shell structure observed in Hildoceras semipolitum . Interrelated to heterochrony is also the concept of "developmental polymorphism", considered as a plausible alternative and more general frame in which to place sexual dimorphism as displayed by Hildoceras bifrons .
The EGU General Assembly, 2013
12 13 Abstract 14 Historical earthquakes of the Gargano Promontory, an uplifted foreland sector i... more 12 13 Abstract 14 Historical earthquakes of the Gargano Promontory, an uplifted foreland sector in southeastern Italy, 15 have been usually regarded as generated by inland faults. Some have been associated with activity 16
Bollettino Della Societa Geologica Italiana, 2009
Geosciences, 2018
Linear sand bodies with ridged or mounded morphology are commonly referred to as "sand ridges". T... more Linear sand bodies with ridged or mounded morphology are commonly referred to as "sand ridges". Their origin may reflect a great variety of depositional processes and environments, although many examples from modern shelves include near-shore transgressive deposits formed during the last post-glacial sea level rise. These transgressive sand ridges, however, are not present on all the margins drowned during this interval, indicating that local environmental factors contribute to their formation and preservation. Transgressive sand ridges are recognized on the South Adriatic shelf in water depths between 90 and 120 m, where they overlay a major unconformity originated during the last glacial sea level fall and lowstand. In contrast, they are absent on the Central Adriatic shelf, where transgressive deposits above the glacial unconformity fill erosional scours without forming relief on the seafloor. The transgressive sand ridges on the South Adriatic shelf appear roughly elongated parallel to the bathymetric contour and are locally as thick as 15-20 m. Core data indicate an overall coarse-grained composition, with a relevant bioclastic component. Their limited distribution reflects the importance of local variation in shelf morphology and sediment sourcing at the onset of sea level rise. In particular, their deposition and preservation are favored in less subsiding shelf sectors characterized by higher gradients and tectonic relief, where transgressive erosion and reworking of pre-existing lowstand deposits is also more efficient.
Geological Society, London, Special Publications, 2020
The NE Sicilian continental margin is largely affected by canyons and related landslide scars. Tw... more The NE Sicilian continental margin is largely affected by canyons and related landslide scars. Two main types of submarine canyons are recognizable: the first type carves the shelf up to depths <20 m, a few hundred metres from the coast, acting as a main collector for sediments transported by hyperpycnal flows and/or littoral drift. These canyons mostly have a V-shaped cross-section and are characterized by a strong axial incision, where a network of dendritic gullies carving the canyon flanks converges. The second type of canyon occurs where the shelf is wider, hindering the direct connection between the subaerial and submarine drainage system. This setting exhibits canyon heads mostly confined to the shelf break, characterized by a weaker axial incision of the canyon and U-shaped cross-section. A total of 280 landslide scars are recognized in the study area and these are divided into three groups according to their morphology and location. A morphometric analysis of these scars...
The acquisition of high resolution morpho-bathymetric data on the Calabro Tyrrhenian contine... more The acquisition of high resolution morpho-bathymetric data on the Calabro Tyrrhenian continental margin (Southern Italy) enabled us to identify several mass-wasting processes, including shallow gullies, shelf-indenting canyons and landslides. In particular, we focus our attention on submarine landslides occurring from the coast down to -1700 m, with mobilized volumes ranging from some hundreds up to tens of millions of cubic meters. These landslides also show a large variability of geomorphic features in the headwall, translational and toe domain. Based on their morphology and distribution, four main classes of coastal/submarine landslides have been recognized: a) rocky coastal/shallow-water failures characterized by large hummocky deposits offshore; b) large-size and isolated scars with associated landslide deposits, mostly occurring on open slope environment and lower part of tectonically-controlled escarpments; c) a linear array of coalescent and nested landslide scars occur...
Marine Geology, 2017
Abstract Multibeam bathymetry, high-resolution seismic profiles and seafloor samples have been an... more Abstract Multibeam bathymetry, high-resolution seismic profiles and seafloor samples have been analyzed to characterize depositional and erosional dynamics recorded pro-deltaic deposits and outer shelf sediments along of a sector of the NE Sicilian margin (southern Tyrrhenian Sea). The deltaic deposits cover an area of ca. 15 km 2 in front of the Mazzarra River, and are morphologically characterized by waveforms trending overall along strike and incised cross-strike gullies of variable length. The gullies are shallow and characterized by small, coaxial erosive scours in the inner-middle shelf, whereas they become larger and deeper in the outer shelf-upper slope, in relation to the marked increase of slope gradients at the shelf break. Here, the wider gullies are characterized by a frame of crescent-shaped bedforms interpreted as cyclic steps, indicating the occurrence of sedimentary gravity flows in supercritical regime. Prodelta waveforms are widespread between − 50 and − 120 m, with wave lengths of 34–110 m and wave heights of 0.5–3 m. Morphometric characterization and spatial distribution of the waveforms suggests a main role in their genesis played by hyperpycnal flows, although we cannot discard the possible effect of internal waves or slow deformation processes (i.e., creep). Depositional and erosional features similar to those observed on the seafloor are evident in the subsurface stratigraphy, revealing the onset and growth of the Mazzarra Delta since the Last Glacial Maximum. The post-glacial sea level rise caused lateral shifts of the Mazzarra River mouth controlling migration of depositional lobes and intensity of seafloor incision and sediment reworking, ultimately resulting in the observed wavy bedforms extending from the inner shelf to the upper slope.
Tectonophysics, 2008
Recent seismicity in and around the Gargano Promontory, an uplifted portion of the southern Adria... more Recent seismicity in and around the Gargano Promontory, an uplifted portion of the southern Adriatic Foreland domain, indicates active E-W strike-slip faulting in a region that has also been struck by large historical earthquakes, particularly along the Mattinata Fault. Seismic profiles published in the past two decades show that the pattern of tectonic deformation along the E-W-trending segment of the Gondola Fault Zone, the offshore counterpart of the Mattinata Fault, is strikingly similar to that observed onshore during the Eocene-Pliocene interval. Based on the lack of instrumental seismicity in the south Adriatic offshore, however, and on standard seismic reflection data showing an undisturbed Quaternary succession above the Gondola Fault Zone, this fault zone has been interpreted as essentially inactive since the Pliocene. Nevertheless, many investigators emphasised the genetic relationships and physical continuity between the Mattinata Fault, a positively active tectonic feature, and the Gondola Fault Zone. The seismotectonic potential of the system formed by these two faults has never been investigated in detail. Recent investigations of Quaternary sedimentary successions on the Adriatic shelf, by means of very high-resolution seismic-stratigraphic data, have led to the identification of fold growth and fault propagation in Middle-Upper Pleistocene and Holocene units. The inferred pattern of gentle folding and shallow faulting indicates that sediments deposited during the past ca. 450 ka were recurrently deformed along the E-W branch of the Gondola Fault Zone. We performed a detailed reconstruction and kinematic interpretation of the most recent deformation observed along the Gondola Fault Zone and interpret it in the broader context of the seismotectonic setting of the southern Apennines-foreland region. We hypothesise that the entire 180 km-long Molise-Gondola Shear Zone is presently active and speculate that also its offshore portion, the Gondola Fault Zone, has a seismogenic behaviour. Tectonophysics, Special Issue: "Earthquake Geology: methods and applications" Ridente et al. Accepted, 20.11.2007 of the original orientation of pre-existing faults and tectonic lineaments. This also implies a difficulty in the determination of the present activity and seismogenic potential of foreland deformation zones. Until just a few years ago, the active tectonics of the Italian peninsula was believed to be dominated by SW-NE oriented extension occurring along the axis of the Apennines (Montone et al., 2004) and responsible for severe earthquakes generated by large NW-SE normal faults (Galadini et al., 2001; Valensise and Pantosti, 2001; Fig. 1). The 2002 Molise earthquakes (M=5.8; notice that, if not differently reported, all magnitudes in this paper are from CPTI Catalogue; Gruppo di Lavoro CPTI, 2004; Fig. 1b), however, located to the NE of the Southern Apennine axis, supplied living evidence that in this sector of the chain (i.e. toward the Adriatic Foreland) NW-SE normal faulting gives way to relatively deep E-W, right-lateral seismogenic faults. Further to the east, in the Southern Adriatic Sea, very high-resolution seismic-stratigraphic data indicate that also the marine portion of the Adriatic Foreland is being actively deformed along E-W inherited tectonic structures (Ridente and Trincardi, 2006). This combined evidence suggests that the Southern Adriatic Foreland is affected by active E-W fault systems, both on-and offshore, buried and exposed, possibly organised in regional shear zones (Di Bucci and Mazzoli, 2003; Valensise et al., 2004; both with references). Major E-W-oriented shear zones have been singled out roughly between the latitudes 40°30'N and 42°30'N (Favali et al; 1993; Doglioni et al., 1994). Among them, the Molise-Gondola Shear Zone (MGSZ)
Journal of the Geological Society, 2016
Marine Geology, 2007
The Bari Canyon System (BCS) is a peculiar erosional-depositional feature characterised by two ma... more The Bari Canyon System (BCS) is a peculiar erosional-depositional feature characterised by two main, almost parallel, conduits emanating from a broad crescent-shaped upper slope region. When viewed in cross sections parallel to the margin, BCS appears markedly asymmetric with a right hand (southern) side that is higher and steeper (about 800 m in relief and more than 30°s teep). The left-hand side of the canyon is instead much smoother. As a consequence, bottom currents flowing along the slope from the north enter the canyon and interact with its complex topography leading to preferential deposition on the up-current side of preexisting morphological relief. Where mass-failure deposits generate morphologic relief, outside the canyon, sediment is preferentially deposited up current (N-ward). BCS includes three main EW-oriented sediment conduits: Canyon C, to the south, Channel B, in the central area, and Moat A in the north. Channel B shows a well developed levee deposit on its right-hand side and appears markedly straight and erosional on the upper slope. The deepest portion of Channel B is substantially abandoned and draped but still shows a subdued thickening of the draped unit north (and up current) of pre-existing morphologic relief, confirming the impact of along-slope flowing currents. Canyon C is flanked by erosional walls all the way to the basin floor where deep-sea furrows develop with a NW-SE orientation. Today, dense water formation in the Adriatic is seasonally modulated and displays a significant variability on inter-decadal scales. Dense water formation during glacial intervals was likely different from the modern because most of the North Adriatic shelf was subaerially exposed and the deep water mixing in the south was likely reduced, as suggested by paleoceanographic reconstructions. The growth patterns of BCS since the LGM are characterised by concurrent erosion of the upper portion of Channel B and of the lower portion of Canyon C. It is possible that flows through the straight, narrow and steep upper segment of channel B spill over its right hand levee in ca. 600 m water depth, where the relief of levee B on the channel floor is minimal, and enter Canyon C, where substantial erosion takes place. In this view, the upper portion of Canyon C, where hard grounds and corals are encountered, is flushed by currents characterised by reduced turbidity, while the lower part of Canyon C collects additional flows from upper channel B.
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Papers by Domenico Ridente