Search results for " thrust"
showing 10 items of 59 documents
Growth pattern of underlithified strata during thrust-related folding
2004
Abstract Asymmetric anticlines with overturned or steeply dipping forelimbs and gently dipping backlimbs are generally interpreted as thrust-related folds. Fold asymmetry occurs as a consequence of forelimb rotation. If deformation takes place in environments dominated by submarine sedimentation, the limbs coincide with the slope (depositional surface) and rotation reflects slope steepening. If folds are nucleated in poorly or unlithified deposits, growth geometry also depends on the properties of the media, such as cohesion and the angle of internal friction. For cohesionless deposits, the tilting of the slope influences the equilibrium of the soft sediments, resulting in gravity-driven fl…
Seismotectonics of the active thrust front in southwestern Sicily: hints on the Belice and Selinunte seismogenic sources
2014
We present a seismotectonic model of the active thrust front in western Sicily, which includes the area hit by the 1968 Belice earthquake sequence. The ~40 km long South-WEstern Sicilian Thrust (SWEST) is formed by two aligned albeit non-parallel fault arrays, the Granitola-Castelevetrano Thrust System (GCTS) in the west and the Partanna- Poggioreale Thrust System (PPTS) in the east. The ~NE-SW trending, NW-dipping GCTS straddles from the Pelagian coastline to Castelvetrano, is ~18 km long and composed of two segments, with the northern, ~12 km long one showing geodetic and geologic evidence of active deformation (Barreca et al., 2014). The segment is marked by a sharp gradient in Different…
Understanding paleomagnetic rotations in Sicily: thrust vs. strike-slipe tectonics
2018
The paleomagnetic investigation of the western Sicily Maghrebian belt has revealed since the 1970s that large clockwise (CW) rotations up to 140° with respect to the Hyblean-African foreland occurred synchronous with Tertiary shortening of the chain. The observation that rotations decrease stepwise from internal to external tectono-stratigraphic units led in the 1990s to a widely accepted model postulating that rotational thrust-sheet emplaced during forward orogenic propagation. More recently, other authors suggested that CW rotations from Sicily are conversely the result of late orogenic dextral strike-slip tectonics. Here we report on a paleomagnetic investigation of 30 Jurassic-Eocene s…
Basins at convergent margins: evolution of the Messinian basins developed on top of the Sicilian Fold and Thrust belt
2018
During the Messinian inherited palaeo-topography and ongoing deformation conditioned the depositional environments of the Mediterranean region, already strongly influenced by the effects of the salinity crisis. It occurred mainly in the central region, where seabed at that time is expected to be very uneven and shallower than Western and Eastern Mediterranean. Indeed in this area as from 15 Ma the Sicilian Fold and Thrust Belt (SFTB) was originating, characterized by a multi-stage evolution. Two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts following a thin-skinned thrust-model) and at different time intervals, involved mainl…
Ciminna, First Stop - 27 Thursday
2016
A description of the stratigraphic setting and tectonic evolution of the Late Neogene Ciminna basin (Northern Sicily)
Geodetic, geological and geophysical evidence of active tectonics in south-western Sicily and offshore
2013
tIntegrated geological, geodetic and marine geophysical data provide evidence of active deformation insouth-western Sicily, in an area spatially coincident with the macroseismic zone of the destructive 1968Belice earthquake sequence. Even though the sequence represents the strongest seismic event recordedin Western Sicily in historical times, focal solutions provided by different authors are inconclusive onpossible faulting mechanism, which ranges from thrusting to transpression, and the seismogenic sourceis still undefined. Interferometric (DInSAR) observations reveal a differential ground motion on a SW–NEalignment between Campobello di Mazara and Castelvetrano (CCA), located just west of…
Extensive backthrusting features in the northern Sicily continental margin highlight a late collisional stage of the Sicilian Fold and Thrust Belt
2016
Backthrusting, nappe refolding, and normal faulting frequently characterize late collisional stage of an orogen. Shortening driven by backthrusting is widely reported in the Alpine orogen, and it has been proposed to be responsible for the increase of subsidence. Moreover delamination and backthrusting has been considered as related to subcritical condition of a Coulomb-type accretional wedge (Torres Carbonell et al., 2011). The Sicilian Fold and Thrust Belt (SFTB) was characterized by a three-stage evolution during the last 15 My: two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts in thinskinned thrust-model) and different ti…
Understanding paleomagnetic rotations in Sicily: Thrust vs. transpressive structures
2016
Since the 1970s, paleomagnetic data collected in Sicily have documented large magnitude clockwise (CW) rotations around vertical axis with respect to Africa and the Hyblean foreland. Many Authors argued that rotations arise from rotational thrusting of large coherent nappes coinciding with paleogeographic units. In the forward thrust propagation process, each nappe rotates the overlying nappe stack. This would explain the stepwise decrease of rotation magnitudes from the internal Panormide unit (90°-140°) to the external Saccense unit, yielding no rotation. However, other Authors later proposed that rotations of Sicily are the consequence of dextral shear occurring since late Miocene times …