Academic literature on the topic 'Flysch basin'

Abstract The Vienna Basin is situated at the contact of the Bohemian Massif, Western Carpathians, and Eastern Alps. Deep borehole data and an existing magnetotelluric profile were used in density modelling of the pre-Neogene basement in the Slovak part of the Vienna Basin. Density modelling was carried out along a profile oriented in a NW–SE direction, across the expected contacts of the main geological structures. From bottom to top, four structural floors have been defined. Bohemian Massif crystalline basement with the autochthonous Mesozoic sedimentary cover sequence. The accretionary sedimentary wedge of the Flysch Belt above the Bohemian Massif rocks sequences. The Mesozoic sediments considered to be part of the Carpathian Klippen Belt together with Mesozoic cover nappes of Alpine and Carpathian provenance are thrust over the Flysch Belt creating the third structural floor. The Neogene sediments form the highest structural floor overlying tectonic contacts of the Flysch sediments and Klippen Belt as well as the Klippen Belt and the Alpine/Carpathians nappe structures.

Abstract The formations underlying the Neogene infill of the Vienna Basin are still poorly documented. Until now correlation of subsurface lithostratigraphic units with those of the Rhenodanubian nappe system and the Magura nappe system, outcropping at the basin margins, has been based on extrapolations. A recent drilling campaign in the Bernhardsthal oil field of the northern Vienna Basin in Austria reached the pre-Neogene basement and provided cuttings for biostratigraphic and paleoecological analyses. Based on these data, acquired by using detailed micro- and nanno-paleontological analyses, a Lutetian age (middle Eocene) and a bathyal depositional environment for the Flysch of the Harrersdorf Unit was documented. The lithological similarity of the drilling with the Steinberg Flysch Formation of the Greifenstein Nappe and its Lutetian age suggests, that the middle Eocene part of the Harrersdorf Unit represents a continuation of the Greifenstein Nappe of the Rhenodanubian Flysch, rather than a frontal part of the Rača Nappe of the Magura Flysch as previously thought.

The tectonic units of the Carpathians are considered in terms of the terrain analysis. Carpathathian orogen is build up of three main elements: microcontinental terrains, sutures and flysch-molasse accretionary prism. There are two main terrains: a northern ALCAPA and a southern Tisza-Dacia. Sutures (Fore-Marmarosh suture, Pieniny Klippen Belt and others), marking the ancient oceanic basins, bound these terrains. The Flysch Carpathians are regarded as the Cretaceous-Neogene accretionary prism. Growing the prism was caused by the Alpine subduction of the Carpathian Flysch basin basement beneath both the ALCAPA and Tisza-Dacia terrains.

AbstractThe olistostromes form two belts within the Pieniny Klippen Belt (PKB) in the Northern Carpathians. They mark an early stage of the development of the accretionary prism. The first belt was formed during Late Cretaceous time as a result of subduction of the southern part of the Alpine Tethys. The fore-arc basin originated along this subduction zone, with synorogenic flysch deposits. Huge olistoliths deposited within the Cretaceous–Palaeogene flysch of the Złatne Basin, presently located in the vicinity of the Haligovce village (eastern Slovakia), provide a good example of the fore-arc olistostrome setting. The second belt is related to the movement of the accretionary prism, which overrode the Czorsztyn Ridge during Late Cretaceous–Paleocene time. The destruction of this ridge led to the formation of submarine slumps and olistoliths along the southern margin of the Magura Basin. The Upper Cretaceous – Paleocene flysch sequences of the Magura Basin constitute the matrix of olistostromes. The large Homole block in the Jaworki village represents the best example of the Magura Basin olistolith. Numerous examples of olistoliths were documented in western Slovakia, Poland, eastern Slovakia and Ukraine. The olistostromes formed within the Złatne and Magura basins orginated during the tectonic process, forming the olistostrome belts along the strike of the PKB structure.

Abstract The 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.

AbstractThe Piolit, Pelat (French Alps) and Baiardo (Italian Maritime Alps) units contain Upper Cretaceous carbonate turbidites formations, with minor siliciclastic components. They are flysch formations, linked with the Pyrenean compressive events through their ages and their “subbriançonnais” structural position. Sedimentological, mineralogical (heavy minerals), and geochemical analysis, point to a potential “Pyrenean signature” which would testify the Late Cretaceous collision between the Ibero-Briançonnais terrane and the European plate. A “Dauphinois” origin and basin inversion erosion is proposed for the zircon-tourmaline-rutile (ZTR) bearing Piolit flysch, deposited from the Coniacian to the Campanian. A Penninic origin with tectonic inversion and erosion of former tilted blocks of the European margin from the Turonian to the Paleocene is proposed for the ZTR bearing Pelat flysch. Comparison with the Niesen (Swiss Prealps) and La Ciotat (Provence) flysch depositional context, allows to better constrain the Pyrenean compressive event in the Alpine domain. The Senonian part of the Baiardo flysch, that contains a garnet-dominated heavy mineral association and distinct geochemical trends, is allotted to the Liguro-Piemontais domain and to the Alpine collision stricto sensu.

Vitrinite reflectance and a micro-Raman spectroscopy parameters data set have been acquired on dispersed organic matter of the Maghrebian flysch basin and the Tangiers unit across a NE-SW section in the north-western Rif belt (North Morocco). Thermal maturity shows increasing values from the hinterland to the external unit (from NE to SW). Paleo-thermal indicators show that the internal flysch basin (i.e., the Mauretanian unit) is less mature than the external one, (i.e., the Massylian unit), with Ro% and Ro eq. Raman values ranging from 0.64% to 1.02% (from early mature to late mature stages of hydrocarbon generation). 1D thermal modeling estimates the overburden now totally eroded ranging from 3.1 km to 6.0 km, and has been used as constraint to reconstruct the complete thrust wedge geometry in Miocene times. The reconstructed geometry accounts for high shortening (about 63%) due to the development of an antiformal stack in the frontal part of the wedge made up by the flysch succession. This stacking is interpreted as a consequence of the western translation of the Alboran Domain in the core of the Betic-Rif orogenic system.

During the Early to Late Ordovician the Taconic foredeep in west-central Newfoundland evolved from an underfilled to an overfilled state in response to cratonward advance, thickening, and erosion of the Taconic Orogen. Early orogen-derived sediment in the foreland basin consisted of middle(?) to lake Arenigian deep-water mudstones that accumulated on an inner (craton-facing) slope prism (uppermost parts of Shallow Bay and Green Point formations and correlative units). These deposits are interbedded with and overlie passive-margin slope sediments. In the middle Arenigian to early Llanvirnian, sand from the orogen formed several small, sand-rich submarine fans (Lower Head Formation and correlative units) on the lower reaches of the inner slope and basin plain. The fans may have been fed by closely spaced rivers draining the orogen, as presently occurs in western South America. Only proximal portions of these fans are now exposed. The flysch basin was narrow, constricted by the inner slope and the passive-margin slope, and located a short distance seaward from the buried hingeline of the proto-North American craton. As the orogen thickened sufficiently to override the crustal ramp, the carbonate shelf on the craton drowned, clastic depocentres migrated onto the foundered craton, and a thicker flysch (Mainland Sandstone) accumulated in Llanvirnian-Llandeilian time. In the Caradocian the foreland basin was overfilled with shallow-marine terrigenous sediments (Long Point Formation). Regional flysch dispersal was from a St. Lawrence promontory to a Quebec reentrant.

Abstract The Karpatian deposits of the central part of the Carpathian Foredeep in Moravia, which are deeply buried under the Outer Western Carpathians, provide a unique opportunity to reconstruct the former evolutionary stages of this peripheral foreland basin and its paleogeography. A succession of three depositional units characterized by a distinct depositional environment, provenance, and partly also foreland basin depozone, have been identified. The first depositional unit represents a proximal forebulge depozone and consists of lagoon-estuary and barred coastline deposits. The source from the “local” crystalline basement played here an important role. The second depositional unit consists of coastline to shallow marine deposits and is interpreted as a forebulge depozone. Tidalites recognized within this unit represent the only described tide-generated deposits of the Neogene infill of the Carpathian Foredeep basin in Moravia. The source from the basin passive margin (the Bohemian Massif) has been proved. The third depositional unit is formed by offshore deposits and represents a foredeep depozone. The provenance from both passive and active basin margin (Silesian Unit of the Western Carpathian Flysch Zone) has been proved. Thus, both a stepwise migration of the foredeep basin axis and shift of basin depozones outwards/cratonwards were documented, together with forebulge retreat. The shift of the foreland basin depozones more than 50 km cratonward can be assumed. The renewed thrusting along the basin’s active margin finally completely changed the basin shape and paleogeography. The upper part of the infill was deformed outside the prograding thrust front of flysch nappes and the flysch rocks together with a strip of Miocene sediments were superposed onto the inner part of the basin. The width and bathymetric gradient of the entire basin was changed/reduced and the deposition continued toward the platform. The basin evolution and changes in its geometry are interpreted as a consequence of the phases of the thrust-sheet stacking and sediment loading in combination with sea-level change.