1,721,004 research outputs found
Styles of positive inversion tectonics in the Central Apennines and in the Adriatic foreland: Implications for the evolution of the Apennine chain (Italy)
No full textIntegration of new field structural and geophysical data with existing information from the Apennines chain in Italy and its adjacent Adriatic foreland indicates that the styles of positive inversion tectonics and the modes of interaction between the extensional and the subsequent compressive structures vary.
Starting from the Cretaceous, the contractional deformation induced by the mainly north-directed convergence of Africa/Adria with respect to the European plate promoted the closure of various arms of the Atlantic and the Neo-Tethys oceans, which opened in different times and with distinct orientations.
The mosaic of continental blocks, carbonate platforms, rift basins and oceanic domains with several geometries and orientations with respect to the axis of the subsequent compression, and the resulting heterogeneities within the shallow sedimentary cover and the overall lithosphere, strongly influenced both the structural evolution of the Apennine orogenic belt and the intra-continental deformation within the Adriatic foreland.
Field observations reveal that the steeply E- and W-dipping Mesozoic–Cenozoic normal faults are systematically decapitated by sub-horizontal or gently west-dipping thrusts propagating with short-cut trajectories. Pre-thrusting normal faults were commonly deformed by later thrusts, but little evidence seems to support their entire reactivation as high-angle reverse faults. This suggests that these shallowand
steeply-dipping discontinuities were not suitable to be reutilized by the superficial thin-skinned thrust faults propagating within the sedimentary cover. In contrast, presumably late Paleozoic and Mesozoic W-dipping normal faults appear moderately reactivated in the Adriatic foreland, and strong positive inversion tectonics affect the deeper and buried structural levels of the Apennine chain. Within
the latter, the syn-rift sediments in the hangingwall blocks of the fault-bounded basins were totally extruded and generated the strong uplift of the thinned Adria continental crust.
Finally, the contrasting styles of interactions of the pre-existing normal faults with later thrusts (i.e., passive truncation or positive reactivation) strictly result from the different evolution of the Apennine chain and the combined thin- and thick-skinned modes of deformation of the stretched lithosphere of the Adria plate
Methods for determining Pleistocene-Olocene displacement in active faults reactivating pre-Quaternary structures. Example from the Central Apennines (Italy).
No full textPliocene-Quaternary thrust tectonics and related sedimentation in the outer central Apennines
No full textActive intraplate deformation within Adria: Examples from the Adriatic region.
No full textRecent seismicity recorded in the Adriatic region suggests that active deformation occurs within the Adria
plate. Earthquakes are common in the adjoining chains and in particular along the Northern Apennines, in
the Southern Alps and along the Dinaric–Albanian–Hellenic thrust fronts; in addition, medium-to-low grade
seismicity also affects the foreland and is clustered along two main transects through the centre of the
Adriatic region. The two zones of active deformation correspond to the Mid-Adriatic Ridge and the Gargano
region, and approximately trend NW–SE and E–W, respectively.
Several interpretations have been proposed to explain the deformation observed within the Adriatic foreland,
including a variety of contrasting kinematic and geodynamic models.
We attempted to unravel the complicated structural evolution of the Central Adriatic region by interpreting
industrial and ministerial (shallow and deep) seismic profiles and the recent seismicity recorded in the
Adriatic. The subsurface study allowed us to better understand the structural style, timing and rates of
deformation affecting the Mid-Adriatic Ridge and the Gargano region, and to unravel the relationships of
active deformation with respect to the adjacent chains. The results of our study indicate that the structural
setting and type of seismicity of the Central Adriatic can be explained in terms of active intraplate
deformation with the reactivation of inherited discontinuities
Methods for determining pleistocene-holocene displacement in active faults reactivating pre-quaternary structures. Example from the Central Apennines (Italy)
No full textNeogene-Quaternary evolution of the Central Apennine thrust front: Constraints from sequence and forward balancing of a regional cross-section/Evoluzione neogenico-quaternaria del fronte della catena centro-appenninica: vincoli dal bilanciamento di una sezione geologica regionale
No full textIn this study the outer sector of the Central Apennine of Italy
and the adjacent Adriatic foreland were analysed in order to reconstruct their structural setting and the Neogene-Quaternary evolution of the fold-and-thrust belt.
In the investigated area the thrust front is largely buried
beneath Messinian-Pliocene siliciclastic sediments in the on-shore sector (i.e. peri-Adriatic Basin), and by Pliocene-Quaternary deposits in the adjacent Adriatic Basin (BALLY et alii, 1986; ORI et alii, 1991; CASNEDI & SERAFINI, 1994; ARTONI & CASERO, 1997; MONTEFALCONE,
2000; ARGNANI et alii, 2001; CALAMITA et alii, 2002; BOLIS et alii, 2003). In the inner sector of the chain the Mesozoic-Paleogene carbonate units crop out in the core of two anticlines (the Acquasanta and the M.gna dei Fiori Structures – KOOPMAN, 1983; MATTEI, 1987; CALAMITA et alii, 1991; CENTAMORE et alii, 1992a; INVERNIZZI
& RIDOLFI, 1992; MARSILI & TOZZI, 1995; CALAMITA et alii, 1998); by contrast the top of the carbonate succession abruptly deepens toward the east where it lies at depths of more than 7000 meters below sea level. Here, the thick Pliocene-Quaternary siliciclastic succession is involved in an imbricate thin-skinned fold-and-thrust system with a leading edge located in the Central Adriatic Basin.
A balanced geological cross-section based on surface geologicalstructural surveys and subsurface data (i.e. seismic reflection profiles and well-log data) was constructed with the aim to illustrate the structural setting of the outer sector of the Central Apennines of Italy. This cross-section extends through the Acquasanta anticline, the M.gna dei Fiori anticline, the peri-Adriatic Basin and the Central
Adriatic off-shore, as far as the Italy-Croatia mid-line. The section allowed us to define the geometry of the Central Apennine thrust front, the foreland ramp, and the syn-tectonic basin infill; moreover, by sequential balancing and subsequent forward balancing, the tectonic evolution of the chain-foredeep-foreland system were reconstructed
and the shortening rates were calculated.
Based on this study, the complex structural setting of the Central Apennine fold-and-thrust belt results from the interaction between an extremely thin-skinned and a thick-skinned thrust system.
The former only affects the syn-orogenic siliciclastic deposits
and generally predates the deeper thrust system that cuts across the whole sedimentary cover (i.e. carbonate units and overlying siliciclastic sediments), and locally the basement. The uncoupling between thin and thick-skinned tectonics strictly controls the evolution and migration of the syn-tectonic basins, and influences the sequence of thrust propagation; this latter, with respect to the deeper stratigraphic levels, is mainly toward the foreland. Moreover,
spacing and location of thrust ramps are controlled by pre-existing discontinuities that affected the foreland ramp
Styles of plio-quaternary positive inversion tectonics in the central-southern apennines and in the adriatic foreland
No full textStyes of Plio-Quaternary Positive Inversion Tectonics in the Central-Southern Apennines and in the Adriatic Foreland
No full textIl sollevamemento tardo-pliocenico-quaternario nell’area Periadriatica abruzzese: uno studio integrato basato su dati geologico-strutturali di sottosuolo e sui caratteri geomorfologici del Fiume Pescara
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