118,572 research outputs found
Corrigendum to: Geology of the Victoria quadrangle (H02), Mercury (Journal of Maps, (2016), 10.1080/17445647.2016.1193777)
No full textWhen the above article was first published online, the third author was incorrectly listed as F. Ferranti. This has now been corrected
Late Neogene horizontal and vertical displacement rates during simultaneous contraction and extension in the Southern Apennines orogen, Italy
No full textAssessment of vertical and horizontal displacements and displacement rates within the western Adriatic orogens, where contractional and extensional deformation coexists since the Miocene (PATACCA et alii, 1990; DOGLIONI, 1991), has the potential to supply vital insight into crustal and lithospheric processes operating during continental collision. Using the tight age control on contractional motion provided by synorogenic sequences preserved in outcrop and in petroleum exploration wells, the constraints on extensional motion provided by the crustal structure of the extended hinterland, and the differential elevation of uplifted markers of ancient base level, we establish a regional pattern of vertical and horizontal motion in the Southern Apennines for the last ∼6 Ma, which points to an intricate interplay between lithospheric delamination and crustal structure (FERRANTI & OLDOW, 2005a; 2005b). During latest Miocene to Early Pleistocene, the frontal thrust of the orogen migrated toward the foreland rapidly (∼16 mm/yr) and was accompanied by subsidence with the frontal thrust belt and foredeep remaining at or below sea level. In contrast, the orogenic hinterland experienced extension, which was accompanied by uplift at -0.3 mm/yr along the eastern transition to the contractional belt but net subsidence and formation of the Tyrrhenian basin farther west. Through time, the extensional belt progressively widened toward the northeast at the same rate as the encroachment of the thrust front on the Adriatic foreland. Following a mid-Pleistocene reduction in horizontal displacement rate associated with impingement of the thrust belt on thick crust of the Adriatic interior, the frontal thrust belt and foreland experienced uplift at ∼0.5 mm/yr as contraction stepped to deeper structural levels. Uplift of the eastern margin of the extensional hinterland continued at ∼0.3 mm/yr and is followed by tectonic subsidence along the Tyrrhenian coast of southern Italy. Today, the pattern of mid-Pleistocene displacements continues, as suggested by seismicity and GPS velocities (OLDOW & FERRANTI, 2005). The similarity in migration rates of contractional and extensional fronts across southern Italy over the last 6 million years supports models of crustal delamination and roll-back of the subducted Adriatic slab (ROYDEN et alii, 1987; DOGLIONI, 1991) as a fundamental driving mechanism for deformation along the western margin of Adria. Temporal changes in the vertical and horizontal rates of deformation, however, probably reflect differences in crustal structure and are not directly related to lithospheric processes. The reduction in the horizontal displacement rate associated with the onset of rapid foreland and frontal thrust belt uplift during the Early Pleistocene corresponds to a change from thin - to thick-skinned contraction initiated with the involvement of thick continental crust in regional shortening. Unlike segments of the Apenninic chain in central Italy (LAVECCHIA et alii, 1994; CAVINATO & DE CELLES, 1999), uplift and formation of the Southern Apennine mountain chain was not primarily a response to contractional deformation. Much of the orogenic elevation, at least before the mid-Pleistocene onset of uplift in the frontal thrust belt and foreland, was accrued during the initial stages of extension related to crustal delamination
Morfologia e morfometria del settore ionico del Golfo di Taranto.
Full text linkIl versante Ionico del Golfo di Taranto è caratterizzato dalla presenza di alti strutturali e bacini che
rappresentano l’espressione morfologica di sistemi di faglie pleistoceniche transpressive. La dorsale di
Amendolara si estende per 45 Km in direzione N130°E, ed è caratterizzato dalla presenza di tre alti
batimetrici minori (denominati Amendolara, Rossano e Cariati). Verso NE, la dorsale di Capo Spulico si
estende per 40 Km in direzione !N115°E.
Durante la Campagna Oceanografica “Teatioca” sono stati acquisiti 1100Km2 di dati batimetrici
multibeam e profili sismici monocanale ad alta (Sparker) ed altissima risoluzione (Subbottom Chirp).
L’analisi integrata dei nuovi dati ha consentito di ottenere una sintesi morfostrutturale preliminare dell’area
sud-orientale del Golfo di Taranto [Santoro et al., 2012].
L’insieme dei dati morfometrici evidenzia un ruolo chiave nell’attività traspressiva della faglia che borda
a SW la dorsale di Amendolara, in quanto la regolarità dei pendii rivolti a S è legata alla deformazione e
sollevamento dei versanti, che tende a superare l’effetto dei processi erosivi (versanti a controllo morfostrutturale).
Il processo di basculamento guidato dall’azione della faglia sembra essere all’originedei processi
responsabili dell’erosione gravitazionale canalizzata sui pendii esposti a nord (versanti a controllo morfosedimentario).
Sette ordini di terrazzi sono stati riconosciuti sul top del Banco di Amendolara, attraverso tecniche di
analisi dei picchi nel diagramma di distribuzione delle quote [Passaro et al., 2011]. Tale dato e le statistiche
sui profili estratti dal DTM testimoniano la presenza di tassi differenziali di sollevamento ed un complessivo
tilt (verso E) del settore frontale ionico dell’Appennino Meridionale, in accordo con quanto suggerito in
letteratura [Ferranti et al., 2009].
Bibliografia
Ferranti, L., Santoro, E., Mazzella, M.E., Monaco, C., Morelli, D., (2009). Active transpression in the
northern Calabria Apennines, southern Italy. Tectonophysics, 476 (1-2), 226-251.
Passaro, S., Ferranti, L., de Alteriis, G., (2011). The use of high resolution elevation histograms for mapping
submerged terraces: a test from the Eastern Tyrrhenian Sea and the Eastern Atlantic Ocean. Quat. Int.,
232, 1-2, 238-249.
Santoro, E., Ferranti, L., Passaro, S., Burrato, P., Morelli, D., (2012). Morphometric analysis in the offshore
of the southern Taranto Gulf: unveiling the structures controlling the Late Pleistocene-Holocene
bathymetric evolution. Rend. On. Soc. Geol. It., 21 (2), 1132-1135
Underwater cave systems in carbonate rocks as semi-proxy indicators of paleo-sea levels
No full textUnderwater caves may yield valuable information on changes in sea level, as they can track the position of an ancient sea level to a variable degree of accuracy. Limestone caves, in particular, develop different morphologies as a function of oscillating sea levels. In carbonate settings, when true coastal caves including precise indicators of sea-level such as notches or beach deposits are lacking (which hold true as paleo-sea levels indicators for any type of lithology), ancient stillstand levels are approximated: 1) by determining a former groundwater level for continental karst processes (which subsequently experiences submersion) provided they acted sufficiently close to the coast; 2) by determining a mixing zone of different solutions leading to hyperkarst processes. The wide range of different typologies developed in the limestone coastal belt of the Tyrrhenian Sea (Italy), yields case-histories which can be taken as representative of the relationships between relative changes in sea levels and the evolution of karst systems. In particular, the occurrence of features related to hyperkarst processes can be reliable "semi-proxy" indicators of paleo-sea levels in absence of more precise markers
The NW sector of the Sicily Channel: geometry and evolution of inverted structural lineaments
Full text linkThe 3-D trend of anticline axial planes, fault planes and surfaces has been reconstructed in the offshore area between
the Egadi Islands and the Sciacca High from the interpretation of multichannel seismic reflection profiles and well data
(available from the VIDEPI project database). In particular, isopach maps generated for the five seismic units of age
between Cretaceous and Quaternary allowed highlighting the space-time migration of the tectonic processes. The
western portion of the studied area covers the submerged prolongation of the inner sector of the Sicilian-Maghrebian
chain, limited in the NW and in the SE by two tectonic lineaments running along the western and eastern margins of the
Adventure Bank: the Maghrebian Thrust Front and Adventure Thrust Front, respectively (see Argnani et al., 1986). The
eastern portion is characterized by transpressive zones orientated NNE-SSW identifying the Separation Belt that partly
corresponds to the foreland area which contains the Gela Nappe Thrust.
Age constraints indicate that contraction related to the Sicilian-Maghrebian fold and thrust belt migrated
progressively towards the southeast. The emplacement of the western front is attributable to the Middle-Upper Miocene
while that of the eastern front is Plio-Pleistocene. Within this tectonic framework, two tectonic basins were identified on
the basis of the different trend, age and evolution. The Adventure foredeep exhibits the maximum thickness of 500 m in
correspondence of the Adventure Plateau. Here, the younger Gela foredeep displays minor depth showing a thickness
increase towards the Gela Nappe and the Pantelleria graben.
Positive inversion structures form by the Plio-Pleistocene compressional reactivation of preexisting structures
limiting the Saccense and Trapanese domains were recognized the offshore sector between Mazara and Sciacca.
Moreover, a correlation between the Campobello di Mazara-Castelvetrano alignment as proposed by Barreca et al.,
2013, Ferranti et al., this meeting, and the tectonic units recognized in their offshore prolongation has been recognized.
Therefore, we propose that in this area contractional tectonics is still active (see also Pepe et al., this meeting), and
occurs on high-angle, NW-dipping crustal ramps (Monaco et al., 1996)
Late pliocene-quaternary tectonics of the Matese Massif (Southern Apennines): Late shortening and {"}neotectonic{"} extension,Tettonica tardo pliocenica-quaternaria dei Monti del Matese (Appennino meridionale): Raccorciamenti tardivi e distensione {"}neotettonica{"}
No full textMiddle Pleistocene to Holocene tectonics of the Sannio-Matese Mts. boundary: Geometry, kinematics and fault activity
No full textA multidisciplinary study along the north-eastern and western borders of the Matese and Sannio Mts., respectively, has been devoted to decipher the Quaternary to Recent deformation of this sector of the Apenninic chain (MASCHIO, 2003). The mesostructural and geomorphologic analysis, supported by data from low-magnitude seismic sequences (MILANO et alii, 1999; VILARDO et alii, 2003) has allowed to: (1) map the distribution of Middle Pleistocene-Holocene normal fault systems; (2) assess geometry, kinematics and timing of deformation of the fault systems; (3) estimate averaged slip rates for the main tectonic structures, based on offsets of geomorphologic markers; (4) compare the fault kinematic and seismotectonic frame, (5) suggest a geometric model of the active deformation for this sector of the Apenninic chain, that helps clarify the relationships between exposed faults, historical and instrumental seismicity, and seismicity of boundary segments. In detail, the investigated fault systems present an articulated geometry and a complex kinematics in respect to the NE-SW direction of extension typically observed in the Southern Apennines. The tectonic control of inherited structures on active faulting plays a key role on the geometric arrangement of the arrays, formed by N-S and E-W segments which link each other to NW-SE striking, young deformation zones. Quaternary to Recent deformation appears to be accommodated by slip partitioning both on sub parallel structures and on variously striking but kinematically coordinated faults, active within a non-plane strain environment. The fact that slip is heterogeneously distributed in space is consistent with the focal mechanisms of the 1997-1998 low magnitude seismic sequences (MILANO et alii, 2001; VILARDO et alii, 2003). Inspection of the spatial distribution and differential elevation of remnants of sub-horizontal erosional and/or depositional surfaces, referred to various morphological events, has documented a migration of faulting during the Middle/Upper Pleistocene-Holocene and permitted to estimate vertical slip-rates for most of the segments of the fault systems. The main results are listed as follows: - a NE-dipping fault array in the Matese Mts. is active after 2 Ma (from Sassinoro to Guardiaregia to Roccamandolfi villages) and has a cumulate slip rate up to 0.31 mm/a; - most of the main fault systems of the northern border of the Matese Mts. and of the main antithetic ones of the southern border of the Montagnola di Frosolone are active after 0.7 Ma and have integrated slip rates up to 1.37 mm/a and to 0.33 mm/a, respectively; - range-bounding faults of the Matese and Sannio Mts., together with the N-S oriented Le Piane fault (DI BUCCI et alii, 2002), are active mostly after 0,12 Ma with cumulated slip rate of 1,0 mm/a. We suggest these fault systems are representative of an articulated, NE-dipping seismogenic structure, which is internally constituted of both E-W oriented inherited faults linking major NW-SE younger faults, and has NNW-SSE striking faults at its terminations (i.e. Le Piane and Castelpizzuto faults, towards north and Sassinoro, Collalto and Pescosardo faults, towards south). The cumulate slip rate estimates highlights that most of the strain accumulation is concentrated in the middle of the seismogenic structure, from Sepino-Guardiaregia to Castelpizzuto villages. Slip on the structure boundary can occur both during large earthquakes and low-energy seismic sequences
Architecture and Pliocene to Recent evolution of the offshore prolongation of the Granitola - Castelvetrano Thrust System (Sicily Channel)
Full text linkHigh-resolution, seismic profiles were recorded in the offshore of Mazara - Punta Granitola with the purpose of
reconstructing the architecture and Pliocene to Recent evolution of the south-west prolongation of the Granitola-
Castelvetrano Thrust System, identified as an active structure possibly related to destructive historical earthquakes
(Barreca et al., 2014; Ferranti et al., this meeting).
A number of seismic units were identified. The oldest one is interpreted as representative of the Lower Pliocene
pelagic deposits known in the region as Trubi. Lower-middle Pleistocene calcarenites are widespread along the
continental shelf (CS) between Mazara del Vallo while their top rapidly deepens moving southeast-ward Capo
Granitola. In this area, lower-middle Pleistocene calcarenites are unconformably overlain by the late Pleistocene-
Holocene deposits. These latter are thin or absent NW of Punta Granitola along the CS, at water depth less than ~30 m,
suggesting that this sector experienced uplift during the Quaternary.
Small scale, NW- and SE-displacing reverse faults are observed along the CS where they cut the lower-middle
Pleistocene calcarenites and offset the seafloor. South-eastwards, south-east-verging, reverse faults affect lower-middle
Pleistocene calcarenites as well as the late Pleistocene-Holocene layers, suggesting that fault displacement acted during
the post-LGM.
Growth folding of Upper Pleistocene-Holocene deposits and thrust faults, predominantly dipping to the NW,
affecting Pliocene rocks are observed in the immediate offshore Capo Granitola.
The integration of the new data with those obtained from multi-channel profiles suggests that the active folds and
thrusts are the uppermost expression of steep crustal ramps (Monaco et al., 1996; Lavecchia et al., 2007; Meccariello et
al., this meeting) which upthrust the Saccense platform at depth
Ricerche speleosismologiche nel massiccio del Pollino, Appennino Meridionale. Atti I Convegno Regionale di Speleologia
No full textThrust tectonics in the Picentini Mountains, Southern Apennines (Italy)
No full textDetiled geological mapping carried out in the Picentini Mountains, Southern Apennines, Italy, allowed to reconstruct the geometry of the fold and thrust belt in this region. Contractional structures were formed during multiple episodes of ENE to NNE shortening and were cut during later extension by low- and high-angle normal faults. Based on timing of emplacement and geometrical relationships between thrust units, we worked out a kinematic model of thrust tectonics. Basinal (Sicilid and Lagonegro) units were thrust eastward onto a carbonate-platform-basin system (CPBS) starting in the Serravallian-Torto- nian, and were in turn overridden by the CPBS units by means of deeper decollement thrusts. Later contraction, starting from late Tortonian-Messinian times, built up a 15-km-thick antifonnal stack during SSW-NNE shortening. We applied the forward kinematic model of thrust imbrication to perform a qualitative palinspastic restoration of a regional cross-section through this area, based on published interpreted seismics and other subsurface data. The thrust tectonics of the Picentini Mountains and more northward regions was controlled in the internal sectors mostly by envelopment thrusting of carbonate platform thrust sheets, which formerly were the floor complex of the Tortonian thrust belt, while multiple progressive decollement of the basinal roof complex occurred in the external part of the belt. Shallow crustal extension on low-angle faults with transport direction oblique to orthogonal to contractional transport was responsible for contemporaneous thinning during the accretion of the antiformal stack at deeper structural levels
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