1,720,993 research outputs found
The evolution of the Western Adriatic margin and contiguous oceanic area: new problems and working hypotheses
No full textNouvelles datation et interprération de la succession sédimentaire de Sant'Angelo di Brolo(Monts Péloritains;Italie Méridionale): conséquences pour la paléogéographie Mésozoique de la région Thétydée de la Méditerranée Centrale
No full textBiostratigraphic and petrographic study of the Oligocene-lower Miocene successions of the external oceanic units in the Apennines and Sicilian Maghrebides.
No full textStratigraphy, age and petrography of the Beni Issef successions (External Rif; Morocco): insights for the evolution of the Maghrebian Chain.
No full textThe Numidian Flysch: a guide formation for the reconstruction of the paleogeography and tectono-sedimentary evolution of Southern Apennines
No full textThe Numidian Flysch shows constant lithological features from the strait of Gibraltar to central Italy. It is characterized by quartzarenites showing grains of monocrystalline, rounded and frosted quartz, and by kaolinitic mudstones. This research has pointed out that in the southern Apennines 1) the Numidian Flysch was deposited exclusively in the Campania-Lucania carbonate platform and in the Lagonegro-Molise basin, both located on the Apulian continental margin, and never is present in tectonic units originated from the oceanic area located west of that margin; 2) in the axial zone of the Lagonegro basin it stratigraphically follows a formation consisting of varicoloured clays (Argille Varicolori Auct.); 3) its age is limited to the early-middle Langhian, that is to say, it begins to sediment about
7 million years later than in the Maghrebian chain and deposited for a time span limited to 1-1.5 Ma. The thickness of the Numidian Flysch gradually decreases towards the north from about 600-1,000 meters to a few tens of meters and in some of the northeastern outcrops it is represented only by some layers of quartzarenites. This is accompanied by a decrease in size of the particles becoming more and more finer. In addition, northwards and frequently in the same section, a lower mineralogical and textural maturity (from quartzarenites to litharenites, and presence of abundant matrix, sub-angular, polycrystalline and deformed quartz grains) is well recognizable. In the Campania-Lucania carbonate platform the Numidian Flysch evolves to pelagic marly-clayey deposits, followed
by mineralogically immature turbidite sandstones of Serravallian age. In the Lagonegro basin the Numidian Flysch replaces Cretaceous-lower Miocene turbidite deposits, consisting of limestones and red marls, on the western side of the basin, variegated clays in the axial zone and calcareous turbidites or variegated clays in the eastern side.
Since the late Langhian, it evolves to pelagic sediments followed by lower Tortonian immature turbidite sandstones. In the successions of the Molise basin the Numidian Flysch is interbedded in a succession consisting of calcareous turbidites and pelagic limestones and marls, reaching the Messinian.
The lithological features and the age of the Numidian Flysch in central-southern Apennines, therefore, point out an evolution different from that of the Numidian Flysch of the Maghrebian chain. During the early Miocene, a paleogeographic barrier or other unknown obstacles prevent Numidian sands from reaching the south-Apenninic domains. In the early Langhian, the disappearance of these obstacles allows sands to reach the deep basins located on the Apulian margin.
In the late Langhian the Numidian sedimentation is canceled and replaced by mainly pelagic sediments, which will evolve to foredeep deposits in the Serravallian-Messinian time span. In addition, the significant presence of feldspathic and lithic grains testifies a double detrital supply: polycyclic quartzose sands and kaolinitic mudstones from the African craton and metamorphic and plutonic grains from the Hercynian or older rocks of the internal units of the southern Apennines.
The Numidian Flysch of the southern Apennines allows to assign the tectonic units in which is present to the Campania-Lucania carbonate platform or to different zones of the Lagonegro-Molise basin and therefore is of great importance in the reconstruction of both the Mesozoic-Cenozoic paleogeography and a tectono-sedimentary evolution very difficult to decipher, given the convergence of sedimentary facies in the Apenninic deep basins since Cretaceous to Miocene, the presence of several tectonic phases and of out of sequence and back-thrusts
Stratigraphy and tectonics of an Internal Unit of the southern Apennines: implications for the geodynamic evolution of the peri-Tyrrhenian mountain belt
No full textThe Parasicilide succession is a key element of the southern Apennine orogen, being originally located in the distal portion of the Apulian palaeomargin, at the Neotethys ocean-continent transition. The succession, presently included in the upper nappe complex of the thrust belt, has been described elsewhere as a `broken formation'. However, detailed investigations carried out in the Sele Valley point out that there the Parasicilide Unit is characterized by a coherent stratigraphy. Therefore, in the study area, these rocks form a coherent sheet of distal continental margin/oceanic sedimentary cover material included within the peri-Tyrrhenian mountain belt. Stratigraphic and structural constraints obtained from both pre-and syn-orogenic deposits - the latter including both foredeep and thrust-top basin sediments - suggest that the pre-orogenic part of the Parasicilide succession subsided into the Apennine foredeep in the first part of the Burdigalian. The studied rocks were then involved in thrusting prior to late Burdigalian/early Langhian times
The Numidian Flysch: a guide formation for the reconstruction of the paleogeography and tectono-sedimentary evolution of Southern Apennines
No full textThe Numidian Flysch shows constant lithological features from the strait of Gibraltar to central Italy. It is
characterized by quartzarenites showing grains of monocrystalline, rounded and frosted quartz, and by kaolinitic
mudstones. This research has pointed out that in the southern Apennines 1) the Numidian Flysch was deposited exclusively
in the Campania-Lucania carbonate platform and in the Lagonegro-Molise basin, both located on the Apulian
continental margin, and never is present in tectonic units originated from the oceanic area located west of that margin;
2) in the axial zone of the Lagonegro basin it stratigraphically follows a formation consisting of varicoloured clays
(Argille Varicolori Auct.); 3) its age is limited to the early-middle Langhian, that is to say, it begins to sediment about
7 million years later than in the Maghrebian chain and deposited for a time span limited to 1-1.5 Ma.
The thickness of the Numidian Flysch gradually decreases towards the north from about 600-1,000 meters to a
few tens of meters and in some of the northeastern outcrops it is represented only by some layers of quartzarenites. This
is accompanied by a decrease in size of the particles becoming more and more finer. In addition, northwards and frequently
in the same section, a lower mineralogical and textural maturity (from quartzarenites to litharenites, and presence
of abundant matrix, sub-angular, polycrystalline and deformed quartz grains) is well recognizable.
In the Campania-Lucania carbonate platform the Numidian Flysch evolves to pelagic marly-clayey deposits, followed
by mineralogically immature turbidite sandstones of Serravallian age. In the Lagonegro basin the Numidian
Flysch replaces Cretaceous-lower Miocene turbidite deposits, consisting of limestones and red marls, on the western
side of the basin, variegated clays in the axial zone and calcareous turbidites or variegated clays in the eastern side.
Since the late Langhian, it evolves to pelagic sediments followed by lower Tortonian immature turbidite sandstones. In
the successions of the Molise basin the Numidian Flysch is interbedded in a succession consisting of calcareous
turbidites and pelagic limestones and marls, reaching the Messinian.
The lithological features and the age of the Numidian Flysch in central-southern Apennines, therefore, point out
an evolution different from that of the Numidian Flysch of the Maghrebian chain. During the early Miocene, a paleogeographic
barrier or other unknown obstacles prevent Numidian sands from reaching the south-Apenninic domains. In the
early Langhian, the disappearance of these obstacles allows sands to reach the deep basins located on the Apulian margin.
In the late Langhian the Numidian sedimentation is canceled and replaced by mainly pelagic sediments, which will
evolve to foredeep deposits in the Serravallian-Messinian time span. In addition, the significant presence of feldspathic
and lithic grains testifies a double detrital supply: polycyclic quartzose sands and kaolinitic mudstones from the African
craton and metamorphic and plutonic grains from the Hercynian or older rocks of the internal units of the southern
Apennines.
The Numidian Flysch of the southern Apennines allows to assign the tectonic units in which is present to the
Campania-Lucania carbonate platform or to different zones of the Lagonegro-Molise basin and therefore is of great importance
in the reconstruction of both the Mesozoic-Cenozoic paleogeography and a tectono-sedimentary evolution
very difficult to decipher, given the convergence of sedimentary facies in the Apenninic deep basins since Cretaceous to
Miocene, the presence of several tectonic phases and of out of sequence and back-thrusts
The Numidian Flysch: A guide formation for the reconstruction of the paleogeography and tectono-sedimentary evolution of southern Apennines
No full textBiostratigraphic constraints for the paleogeographic and tectonic evolution of the Alpine Central-Western Mediterranean chains (Betic, Maghrebian and Apenninic chains)
No full textNelle catene alpine del Mediterraneo centro-occidentale, i sedimenti che testimoniano l’evoluzione ad avanfossa, e pre-datano l’inizio della tettonica compressiva, nei bacini dei domini continentali interni risultano di età Oligocene superiore-Aquitaniana, mentre quelli dei domini oceanici del Bacino dei Flysch Maghrebidi e dell’Oceano Lucano si depositano fino al Burdigaliano superiore. L’età della base dei più antichi depositi di up-thrust, discordanti sulle unità dei Domini Interni, è burdigaliana, mentre un’età langhiana è stata documentata alla base delle successioni discordanti sulle unità del Bacino dei Flysch-Oceano Lucano. L’età dell’inizio della deformazione compressiva, pertanto, è ben accertata sia nei Domini Interni (Aquitaniano superiore-Burdigaliano inferiore) sia nel Dominio del Bacino dei Flysch-Oceano Lucano (Burdigaliano superiore-Langhiano inferiore). La chiusura dei domini oceanici e la collisione continentale tra la Microplacca Mesomediterranea e le placche principali del Mediterraneo centro-occidentale hanno avuto luogo tra il Burdigaliano terminale e il Langhiano medio. Ad esse si è accompagnato un generale back-thrusting di terreni delle Unità del Bacino dei Flysch al di sopra delle Unità Interne. Dall’esame di tutti i dati biostratigrafici disponibili non risultano evidenze di significativi diacronismi nell’evoluzione tettonica che ha portato all’individuazione dello stadio di avanfossa e alla costruzione di paleo-catene nell’intervallo di tempo che va dall’Oligocene terminale al Miocene medio. Infine, recenti dati biostratigrafici e petrografici su alcune unità appenniniche, come le Unità Sub-liguri e Toscane e l’Unità Lungro-Verbicaro in Calabria settentrionale, mettono in discussione le ricostruzioni paleogeografiche e l’evoluzione tettonica più comunemente accettate dei Domini Appenninici
The succession of the Val Marecchia Nappe (Northern Apennines, Italy) in the light of new field and biostratigraphic data
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