1,721,157 research outputs found
The Messinian events within tectono-stratigraphic evolution of the Southern Laga basin (Central Apennines,Italy)
No full textA cyclic two-mode accretion of the external orogenic wedge in the late Miocene-Pleistocene Central Apennine foreland basin system (Italy)
No full textLa sezione stratigrafica del T. Parola (Salsomaggiore, Parma; Appennino Emiliano): confronto con le successioni ipoaline messiniane del margine appenninico padano
No full textMessinian events in a rapidly subsiding and tectonically controlled foreland basin:the Southern Laga Basin (Central Apennines, Italy)
No full textThe Pliocene-Pleistocene Stratigraphic And Tectonic Evolution Of The Central Sector Of The Western Periadriatic Basin Of Italy.
No full textThe Central portion of the Western Periadriatic Basin is a foreland basins systems associated to the Central Apennine Outer Orogenic Wedge that stretches along the Marche and Abruzzi regions of Italy; an area that has been studied since long time and where a plenty of surface and subsurface data are available. The present study is aimed to review and synthetize these data, add new surface and subsurface data in order to define a firm stratigraphic and tectonic framework that is base for the reconstruction of the Pliocene-Pleistocene tectonic-stratigraphic evolution of the Central portion of the Western Periadriatic Basin. The study integrates field mapping, published geological maps, seismic lines, well logs and an updated chronostratigraphic scheme. Six major NNE-SSW thrust stacks and eight unconformity bounded stratigraphic units have been defined; then, a NE-SW oriented zone separates a northern from a southern sector which have differences in structural styles, amount of shortening, basins' widths and thicknesses of stratigraphic units. Despite these differences, the deformation timing, the depositional history and the migration of basins system are common in both sectors and eight tectonic-stratigraphic evolutionary stages have been reconstructed with sequential restoration of two representative cross-sections.
The results highlight that the Pliocene-Pleistocene stratigraphic and tectonic evolution of the Central Western Periadriatic Basin preserves the records of supra-regional and global controls which drive thrust propagation, orogen growth, basins' migration and basins' sedimentary infill. In particular, the stratigraphy preserves global third-order eustatic/climatic changes that have a strict feed-back and concomitance with tectonic pulses. The latter are regulated 1) by cyclic growth of an orogenic wedge undergoing coeval erosion and sedimentation and 2) by eastward retreat of a westward subducting and flexing continental lithosphere
Growth rates and two-mode accretion in the outer orogenic wedge - foreland basin system of Central Apennine (Italy)
No full textThe Central Apennine foreland basin system in the Marche and
Abruzzi regions of Italy preserves the eastern leading edge of the
Apennine orogenic wedge, formed from late Miocene to Pleistocene.
Four thrust stacks make up this external portion Central Apennine
orogenic wedge; they progressively propagated towards the east,
accreted the foredeep basin deposits and simultaneously shifted the depocenters of foredeep and wedge-top basins. An updated chronostratigraphic scheme, integrating recent numerical ages and new GSSP of the Mediterranean area, made it possible to quantify the following rates averaged on time interval of hundreds of thousands years: 1) migration rates of the leading edges of the orogenic wedge (21.47 mm/y); 2) depocenter migration rates of foredeep (9.4 mm/y) and wedge-top (5 mm/y) basins; 3) sedimentation rates in fore deep (2.13 mm/y) and wedge-top (1.1 mm/y) depocenters. The values obtained show that the late Miocene-Pleistocene growth of this orogenic wedge can be envisaged as a cyclic repetition of two accretion modes. A fast-accretion mode, or paroxismal phase, associated with creation of a new thrust front, widespread erosion and widening of the orogenic wedge. Since the late Miocene, three paroxismal phases occurred (around 5.6 M.a., 4.35 M.a and 3.59 M.a.). In the slow-accretion mode, the thrust front did not advance and the orogenic wedge was shortened by out-of-sequence thrusts distributed over the entire wedge; sedimentation rate overcame tectonic deformation and the height of the wedge was increased by the deposition of kilometers-thick marine and continental sediments. This two-mode accretion, common to other orogenic wedges on longer-term periodicity, can be considered typical of orogens and might help in foreseeing the evolution and growth rates of other outer orogenic wedges
Tassi e modalità d'accrezione del Cuneo Orogenico Esterno dell'Appennino Centrale (COAEC) dal Miocene superiore al Pleistocene (Appennino centrale, Italia)
No full textSequential balancing of growth structures, a late Tertiary example from the central Apennines.
No full textDuring the late Tertiary, the external front of the Central Apennines migrates towards the Adriatic foreland basin of the Marche and Abruzzi regions. The outermost synsedimentary growth structure, i.e. the buried Tortoreto-Campomare imbricate fan, was analysed using a seismic reflection line and borehole data. The growth structures record the interaction of tectonic and sedimentary processes at a scale of a few kilometres. The syntectonic sedimentary units form progressive unconformities along the Tortoreto-Campomare thrust panel and are used to unravel the geometric evolution of this buried external front of the Apennines. A sequential balancing method is used to restore unconformity surfaces to their most plausible initial configuration. This methodology allows the reconstruction of nine evolutionary stages for the studied structure since the Pliocene (≈ 4 Ma). These stages define the local geometry of the foredeep basin during and after each unconformity. As each unconformity surface represents a palaeotopography, nine successive topographic surfaces have been restored. The progressive unconformity formed close to the hinge of the Tortoreto-Campomare thrust panel. The cut/seal relationships between the tip of the thrusts and the stratigraphie units constrain the timing of thrusting, and define a local break-back sequence. However, synchronous and out-of-sequence thrusting also occurred at different stages of the structure growth. The time interval of activity and the thrust displacements calculated by cross section restorations allow the estimation of compressional rates, these ranging between 0.12mm/y and 4.25 mm/y. The former value is comparable to displacement rates in previous literature. Despite limitations, this sequential balancing technique is promising and useful for the study of growth folds
Modello sedimentario e di flessurazione di un tratto del margine adriatico in un settore dell'Appennino Centrale
No full textP. Casero (Total S.A.
Evidenze di tettonica polifasata lungo la linea di Boscochiesanuova (Alti Lessini,Verona).
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