Articoli di riviste: "Syn-sedimentary tectonics"

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Alvarenga, Renata dos Santos, Juliano Kuchle, David Iacopini, Karin Goldberg, Claiton Marlon dos Santos Scherer, George Pantopoulos e Patrycia Leipnitz Ene. "Tectonic and Stratigraphic Evolution Based on Seismic Sequence Stratigraphy: Central Rift Section of the Campos Basin, Offshore Brazil". Geosciences 11, n. 8 (12 agosto 2021): 338. http://dx.doi.org/10.3390/geosciences11080338.

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The rift section of the Brazilian basins represent the sedimentary record associated with the first stages of Gondwana break-up in the Early Cretaceous phase (Berriasian to Aptian). The rift succession of the Campos Basin constitutes one of the main petroleum systems of Brazil’s marginal basins. This interval contains the main source rock and important reservoirs in the Lagoa Feia Group deposits. The Lagoa Feia Group is characterized by siliciclastic, carbonate and evaporite sediments deposited during the rift and post-rift phases. Despite the economic relevance, little is known in stratigraphic terms regarding this rift interval. To date, most studies of the Lagoa Feia Group have adopted a lithostratigraphic approach, while this study proposes a tectonostratigraphic framework for the deep-rift succession of the Campos Basin (Lagoa Feia Group), using the fundamentals of seismic sequence stratigraphy. This work also aims to establish a methodological and practical procedure for the stratigraphic analysis of rift basins, using seismic data and seismofacies, and focusing on tectonicstratigraphic analysis. The dataset comprised 2D seismic lines, core and lithological logs from exploration wells. Three seismic facies were identified based on reflector patterns and lithologic data from well cores, providing an improved subdivision of the pre-, syn- and post-rift stages. The syn-rift stage was further subdivided based on the geometric patterns of the reflectors. Tectonics was the main controlling factor in the sedimentary succession, and the pattern and geometry of the seismic reflectors of the syn-rift interval in the Campos Basin allowed the identification of three tectonic systems tracts: (i) a Rift Initiation Systems Tract; (ii) a High Tectonic Activity Systems Tract and (iii) a Low Tectonic Activity Systems Tract.

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Gasparo Morticelli, Maurizio, Vera Valenti, Raimondo Catalano, Attilio Sulli, Mauro Agate, Giuseppe Avellone, Cinzia Albanese, Luca Basilone e Calogero Gugliotta. "Deep controls on foreland basin system evolution along the Sicilian fold and thrust belt". Bulletin de la Société Géologique de France 186, n. 4-5 (1 luglio 2015): 273–90. http://dx.doi.org/10.2113/gssgfbull.186.4-5.273.

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Abstract Neogene-Quaternary wedge-top-basins arose during the Sicilian fold and thrust belt (FTB) build-up. The infilling sedimentary successions are: i) middle-upper Miocene silicoclastics succession, accommodated on top of the accreted Sicilide and Numidian flysch nappes; ii) upper Miocene-lower Pliocene deepening-upwards sediments unconformably overlying the inner Meso-Cenozoic deep-water, Imerese and Sicanian thrust units; iii) Upper Pliocene-Quaternary coastal-open shelf deposits unconformably covering (in the outer sector of the FTB) a tectonic stack (Gela thrust system). These successions are characterized by a basal unconformity on the deformed substrate believed to be the depositional interface common both to the coeval wedge-top and foredeep basins. The tectono-sedimentary evolution of the syn-tectonic basins was controlled by the progressive deepening of the structural levels, which were active during the growing of the FTB. The palinspastic restoration of a crustal geological transect in central Sicily points to: i) the occurrence of two subsequent, basal main thrusts (MT1 and MT2) active during the Neogene-middle Pleistocene tectonic evolution, as well as ii) a decrease in slip- and shortening-rate, estimated for the later MT2 as compared to earlier MT1 basal main thrust. The foreland-basin system evolution recorded during these two steps suggests: – the regional lithofacies distribution, during late Tortonian-early Pliocene, accounted for a wide depozone including the Iblean plateau and its offshore;– a crucial change was recorded by the late Pliocene-Pleistocene wedge-top depozone, when the deeper basal main thrust (MT2) involved and thickened (in the inner sector of the FTB) the crystalline basement (thin- to thick-skinned thrust tectonics); this change influenced the depozones, progressively narrowing up to the present-day setting. As regards this general evolutionary framework, thin-skinned and thick-skinned thrust tectonics can be recognized in the Sicilian FTB evolution. The late Tortonian-early Pliocene, thin-skinned thrust tectonics include two main tectonic events, a “shallow-seated” Event 1 and a “deep-seated” Event 2, with the Pliocene-Pleistocene thick-skinned thrust tectonics representing a third tectonic event (Event 3).

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Giannerini, Gérard, Guillaume Sanchez, Dimitri Schreiber, Jean-Marc Lardeaux, Yann Rolland, Antoine Bellando de Castro e Victorien Bauve. "Geometry and sedimentary evolution of the transpresssive Roquebrune-Cap Martin basin: implications on the kinematics and timing of the Nice arc deformation during Miocene times, SW Alps". Bulletin de la Société Géologique de France 182, n. 6 (1 novembre 2011): 493–506. http://dx.doi.org/10.2113/gssgfbull.182.6.493.

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Abstract The Roquebrune-Cap Martin basin (RCMB), developed along the eastern rim of the Nice arc, represents an exclusive sedimentary marker constraining the timing of the deformation in the Nice arc (southern Subalpine chain) during Miocene times. Structural and sedimentological analyses as well as 3D geometrical modeling of the RCMB revealed morphological, structural and sedimentological features characterizing an active tectonic control of the sedimentary infills and the basin development. Structural and microstructural analyses along the eastern boundary of the Nice arc evidenced a N-S left-lateral strike-slip ‘en echelon’ faults system named Mont Gros-St Agnès Castillon relayed by the Biancon E-W thrusts and sheets. The formation of the RCMB appears to be genetically linked to these strike-slip ‘en échelon’ faults. Such characteristics include the presence of the Mont Gros strike-slip fault structural high relief bounding the RCMB to the West, the West-East asymmetry of the sedimentary infill with a laterally transition facies from breccias directly below the fault relief to conglomerates and sandstones in the central part of the basin and the presence of mass wasting in all structural levels of the basin. The onset and the evolution of the basin were driven by transpresssive tectonics, generating a deep and narrow tectonic depression, bounded by steep tectonically controlled slopes. The transpresssive character of the eastern Nice arc boundary where the syn-tectonic RCMB is hosted, accommodate a general southward translation of the Nice arc in response to a N-S shortening regime. The sedimentological and previous paleontological analyses suggest that the activity of the eastern Nice arc transpresssive boundary generating the RCMB and thus the southward motion of the Nice arc, started during the Early Miocene (Aquitanian), continuing through the Late Miocene (Tortonian). The style and the timing of the syn-sedimentary deformation of the Nice arc is coherent in space and time with the one affecting the Digne and Castellane arc.

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Burrel, Laura, Antonio Teixell, David Gómez-Gras e Xavier Coll. "Basement-involved thrusting, salt migration and intramontane conglomerates: a case from the Southern Pyrenees". BSGF - Earth Sciences Bulletin 192 (2021): 24. http://dx.doi.org/10.1051/bsgf/2021013.

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The northern margin of the Organyà basin (Southern Pyrenees) has a complex structure in which syn-rift Lower Cretaceous carbonates flank a wide Keuper evaporite province, featuring the leading edges of the basement-involved thrust sheets of the Pyrenean antiformal stack. Recent studies show that Keuper diapirs and salt walls grew during the Cretaceous extensional episode, conditioning the development of differentiated depocenters and minibasins. The role of salt tectonics during the Pyrenean orogeny has not been addressed in previous structural studies, but present-day cross-sections indicate a Keuper evaporite-bearing vertical thickness of up to 3000 m in the Senterada-Gerri de la Sal area. We infer that salt migration was a determinant mechanism in triggering a gentle northward tilting of the Organyà basin during the Eocene-Oligocene, recorded in the La Pobla de Segur and Gurp syn-tectonic conglomerates in a large north-directed onlap, opposite to the main sedimentary influx direction. Contemporaneously, we interpret that salt migration, promoted by conglomerate differential loading, enabled the sinking and rotation of the unrooted Nogueres thrust units (têtes plongeantes). We use new and published structural data for the Lower Cretaceous margin of the Organyà basin, combined with structural and clast provenance data from the Cenozoic alluvial fan conglomerates of La Pobla and Gurp, to understand the Lutetian to late Oligocene evolution of the northern margin of the Central South-Pyrenean Unit. The tectono-sedimentary evolution of this area and the salt evacuation patterns are closely related to the exhumation history of the stacked Paleozoic thrust sheets of the Pyrenean hinterland to the north. In this study, we correlate the movements over a mobile substratum and the paleogeographic changes of conglomeratic basins at the toe of an exhuming orogenic interior.

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Demory, François, Gilles Conesa, Julien Oudet, Habib Mansouri, Philippe Münch, Jean Borgomano, Nicolas Thouveny, Juliette Lamarche, Franck Gisquet e Lionel Marié. "Magnetostratigraphy and paleoenvironments in shallow-water carbonates: the Oligocene-Miocene sediments of the northern margin of the Liguro-Provençal basin (West Marseille, southeastern France)". Bulletin de la Société Géologique de France 182, n. 1 (1 gennaio 2011): 37–55. http://dx.doi.org/10.2113/gssgfbull.182.1.37.

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Abstract The present study proposes to estimate the influence of climate, eustatism and local tectonics on the sedimentation of a basin margin at the syn-rift to post-rift transition. For that, paleomagnetic measurements were performed on a marine marly-calcareous sedimentary succession ranging from Upper Oligocene to Lower Miocene and located on the northern margin of the Liguro-Provençal basin. The magnetostratigraphic record is correlated to the reference geomagnetic polarity scale [ATNTS04, Lourens et al. 2004] with the help of biostratigraphy based on calcareous nannofossils and planctonic foraminifers [Oudet et al., 2010]. The resulting age model shows that the 100 m-thick sedimentary succession covers a time span of 5 m.y. from the Late Chattian to the Early Burdigalian. Despite several exposure surfaces and a change in the sedimentation rate, no significant hiatus of sedimentation is documented. In addition, we also estimate the paleoenvironmental evolution through the sedimentary succession. Comparing the dated paleoenvironmental reconstruction with global δ18O and sea level curves [Miller et al., 2005], we show that the Carry-le-Rouet succession is an excellent paleoclimatic archive. Indeed, coral reefs developed at the glacial-interglacial stage transition marking the end of the Oligocene. In addition, the most diversified coral reefs occurred during the warmest period of the Aquitanian. During rifting, bathymetric variations recorded in the studied succession are related to local synsedimentary tectonics whereas, during oceanic crust accretion, global sea level changes influence the sedimentation. This result allows to characterise and to accurately date the break-up unconformity at 20.35 Ma.

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John-Joe, Traynor. "Arenig sedimentation and basin tectonics in the Harlech Dome area (Dolgellau Basin), North Wales". Geological Magazine 127, n. 1 (gennaio 1990): 13–30. http://dx.doi.org/10.1017/s0016756800014138.

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AbstractArenig (Ordovician) clastic sediments crop out in the Harlech Dome region (North Wales), and are placed in a single stratigraphic unit: the Allt Lwyd Formation. This unit records a marine transgression onto an erosion surface produced during late Tremadoc arc volcanicity. Four discrete petrofacies are denned, and reflect differing proportions of detritus derived from Tremadoc-type basic-intermediate igneous rocks, and the local sedimentary basement. Initial shallow marine siliciclastic sandstones and conglomerates are overlain by extensive deep water mud-rich units. These generally shallow up into a complex arc-apron deposit, with sediments derived from the eroding Tremadoc arc, as well as from similar, synchronous volcanics. Predominantly epiclastic sandstones and conglomerates were deposited in deltaic and tidal environments in an arc-apron complex, and capped by condensed mudstones and an ironstone, deposited as sea level rose across these systems. Sediments were ponded in north–south orientated troughs and derived from uplifted blocks. Facies and petrofacies distribution were controlled by syn-sedimentary north-south and northeast–southwest faults. The Allt Lwyd Formation was ponded in a fault-controlled basin (the Dolgellau Basin), one of a series of interconnected sub-basins flooded by the Arenig transgression. The sediments preserved reflect deposition during the transgression of a volcanic arc, prior to the extrusion of marginal basin-type volcanics.

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Martín-Martín, Manuel, Francesco Guerrera, Alí Maaté, Rachid Hlila, Francisco Serrano, Juan C. Cañaveras, Douglas Paton et al. "The Cenozoic evolution of the Intrarif (Rif, Morocco)". Geosphere 18, n. 2 (8 febbraio 2022): 850–84. http://dx.doi.org/10.1130/ges02199.1.

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Abstract This paper provides an understanding of the sedimentary-tectonic evolution of the Cenozoic strata of the El Habt and Ouezzane Tectonic Units (Intrarif, External Rif) in Morocco. New data provide information about the depositional architecture and enable a correlation of the evolution of the External Rif in Morocco with that of the Betic Cordillera in Spain and the Tunisian Tell, which provides new insights for hydrocarbon exploration in the region regarding possible source, reservoir, and seal rocks. The reconstructed Cenozoic succession was bio-chronologically defined, and the major unconformities and stratigraphic gaps were identified. The presence of these unconformities allowed three main stratigraphic sequences to be defined by age: Danian p.p., early Ypresian–early Bartonian p.p., and the early Rupelian–early Serravallian p.p. Three secondary stratigraphic sequences in the former upper main sequence were also defined by age: early Rupelian–late Chattian p.p., Burdigalianp.p., and the Langhian–Serravallian p.p. The depositional setting evolved from deep basin during the Late Cretaceous–Paleocene to external platform-slope during the Eocene–Miocene. The Cenozoic sandstones contain metamorphic and sedimentary rock fragments derived from a recycled orogen source area. The clay mineralogy in the Cenozoic strata consists of associations of Ill+(I–S) ± Sme, Ill+(I–S) ± Sme+Kln and Ill+(I–S) ± Sme+Kln+Chl. These associations indicate an initial unroofing in the Paleogene period, then in the Cretaceous period, and finally in the Late Jurassic period during the Eocene–Oligocene. This detritus was followed by variable amounts of a sedimentary mix of Paleogene to Late Jurassic terrains due to several phases of erosion and deposition partly related to syn-sedimentary tectonics during the Miocene. Equivalent features (similar types of sediments, tectofacies, gaps, and unroofing) were also recognized along the Betic Cordillera in Spain and Maghrebian Chain (Morocco and Tunisia) and interpreted as related to a pre-nappe tectonic activity of soft basement folding, which occurred during the Paleogene after the generalized tectonic inversion (from extension to compression) occurred in the Late Cretaceous. The Upper Cretaceous is considered to be the hydrocarbon source rock, while the fractured Eocene and the porous Oligo-Miocene suites are proposed as possible hydrocarbon reservoirs. The Cenozoic stratigraphic architecture and the nappe structure of the region could provide the necessary trap structures.

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Chakraborty, Nivedita, e Subir Sarkar. "Syn-sedimentary tectonics and facies analysis in a rift setting: Cretaceous Dalmiapuram Formation, Cauvery Basin, SE India". Journal of Palaeogeography 7, n. 2 (aprile 2018): 146–67. http://dx.doi.org/10.1016/j.jop.2018.02.002.

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Balázs, Attila, Liviu Matenco e Didier Granjeon. "Thermo-mechanical and stratigraphic numerical forward modelling: recent advances and their joint application in the Pannonian Basin". Földtani Közlöny 149, n. 3 (24 settembre 2019): 183. http://dx.doi.org/10.23928/foldt.kozl.2019.149.3.183.

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Basin analysis and subsidence history provide key insights into sedimentary basin forming mechanisms. Direct observations have long been the only source of information on their thermal and lithological architecture. State of the art modelling techniques today enable the prediction and computation of their formation and evolution constrained by geological field observations, geophysical and deep borehole data. Understanding the inherent connections between large-scale tectonic and local basin-scale surface processes requires the joint application of thermo-mechanical and stratigraphic modelling techniques. To this aim, we combined the thermo-mechanical lithospheric-scale numerical code Flamar and the high-resolution 3D deterministic stratigraphic software DionisosFlow. This joint modelling method quantifies forcing factors, such as crustal and lithospheric thinning, lithospheric flexure, sea-level and climatic variations associated with water and sediment influx and sediment compaction. The modelling shows the migration of extensional deformation in space and time creating deep half-grabens. After a rapid uplift event, the subsequent post-rift times are characterized by continuous kilometre-scale differential vertical movements. The modelled tectonic subsidence and uplift rates and half-graben geometries are imported into the 3D stratigraphic modelling code. Our modelling of a 120 km × 150 km area shows that such scenarios are associated with continental alluvial to shallow-water sedimentation and footwall erosion during the early stages of the syn-rift, followed by rapid deepening during the subsequent syn-rift evolution. Finally, the basins are filled by a large-scale prograding shelf-margin slope system during the post-rift times. We differentiate between unconformities caused by tectonics, sea-level variations or auto-cyclic processes. Our tectonic and stratigraphic results are compared with geological and geophysical constraints from the Pannonian Basin of Central Europe.

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Ali, Syed Haroon, Osman M. Abdullatif, Lamidi O. Babalola, Fawwaz M. Alkhaldi, Yasir Bashir, S. M. Talha Qadri e Ali Wahid. "Sedimentary facies, depositional environments and conceptual outcrop analogue (Dam Formation, early Miocene) Eastern Arabian Platform, Saudi Arabia: a new high-resolution approach". Journal of Petroleum Exploration and Production Technology 11, n. 6 (15 maggio 2021): 2497–518. http://dx.doi.org/10.1007/s13202-021-01181-7.

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AbstractThis paper presents the facies and depositional environment of the early Miocene Dam Formation, Eastern Arabian platform, Saudi Arabia. Deposition of Dam Formation (Fm.) was considered as a restricted shallow marine deposition. Few studies suggest the role of sea-level change in its deposition but were without decisive substantiation. Here, we describe the facies and high-resolution model of Dam Fm. under varying depositional conditions. The depositional conditions were subjected to changing relative sea level and tectonics. High-resolution outcrop photographs, sedimentological logs, and thin sections present that the mixed carbonate–siliciclastic sequence was affected by a regional tectonics. The lower part of Dam Fm. presents the development of carbonate ramp conditions that are represented by limestones and marl. The depositional conditions fluctuated with the fall of sea level, and uplift in the region pushed the siliciclastic down-dip and covered the whole platform. The subsequent rise in sea level was not as pronounced and thus allowed the deposition of microbial laminites and stromatolitic facies. The southeast outcrops, down-dip, are more carbonate prone as compared to the northwest outcrop, which allowed the deposition of siliciclastic-prone sedimentation up-dip. All facies, architecture, heterogeneity, and deposition were controlled by tectonic events including uplift, subsidence, tilting, and syn-sedimentary faulting, consequently affecting relative sea level. The resulting conceptual outcrop model would help to improve our understanding of mixed carbonate–siliciclastic systems and serve as an analogue for other stratigraphic units in the Arabian plate and region. Our results show that Dam Fm. can be a good target for exploration in the Northern Arabian Gulf.

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COCCO, FABRIZIO, e ANTONIO FUNEDDA. "The Sardic Phase: field evidence of Ordovician tectonics in SE Sardinia, Italy". Geological Magazine 156, n. 1 (14 settembre 2017): 25–38. http://dx.doi.org/10.1017/s0016756817000723.

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AbstractDetailed geological mapping, field observations and structural analyses demonstrate that Early Ordovician (‘Sardic’) deformation occurred in the early Palaeozoic successions that are now incorporated in the Variscan Nappe zone of SE Sardinia. This deformation is represented by folds that formed at a shallow depth, lack a significant syn-folding axial planar foliation, and do not affect the overlying Late Ordovician – Devonian sedimentary sequence. These deformation features can be related to the development of the Sardic Unconformity and to calc-alkaline volcanism in several now-scattered terranes of Ordovician northern Gondwana. This reflects a convergent geodynamic setting that in the study sector appears to have failed to reach a continental collisional end-stage. Associating the structural data from this study with those of several published research studies, a preliminary evaluation about which tectonic setting could better fit is proposed. These conditions affected the eastern side of the northern Gondwana margin more or less contemporaneously with the opening of the Rhéic Ocean and the closure of the Qaidam Ocean, before the amalgamation of the Hunia terranes.

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Cardello, Giovanni Luca, Giuseppe Vico, Lorenzo Consorti, Monia Sabbatino, Eugenio Carminati e Carlo Doglioni. "Constraining the Passive to Active Margin Tectonics of the Internal Central Apennines: Insights from Biostratigraphy, Structural, and Seismic Analysis". Geosciences 11, n. 4 (1 aprile 2021): 160. http://dx.doi.org/10.3390/geosciences11040160.

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The polyphase structural evolution of a sector of the internal Central Apennines, where the significance of pelagic deposits atop neritic carbonate platform and active margin sediments has been long debated, is here documented. The results of a new geological survey in the Volsci Range, supported by new stratigraphic constraints from the syn-orogenic deposits, are integrated with the analysis of 2D seismic reflection lines and available wells in the adjacent Latin Valley. Late Cretaceous syn-sedimentary faults are documented and interpreted as steps linking a carbonate platform to the adjacent pelagic basin, located to the west. During Tortonian time, the pelagic deposits were squeezed off and juxtaposed as mélange units on top of the carbonate platform. Subsurface data highlighted stacked thrust sheets that were first involved into an initial in-sequence propagation with top-to-the-ENE, synchronous to late Tortonian foredeep to wedge-top sedimentation. We distinguish up to four groups of thrust faults that occurred during in-sequence shortening (thrusts 1–3; about 55–60 km) and backthrusting (thrust 4). During Pliocene to recent times, the area has been uplifted and subsequently extended by normal faults cross-cutting the accretionary wedge. Beside regional interest, our findings bear implications on the kinematic evolution of an orogenic wedge affected by far-traveled units.

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Drury, S. A., e S. M. Berhe. "Accretion tectonics in northern Eritrea revealed by remotely sensed imagery". Geological Magazine 130, n. 2 (marzo 1993): 177–90. http://dx.doi.org/10.1017/s0016756800009845.

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AbstractNew details from remotely sensed images of the structure and disposition of broad lithological variations in the Pan-African of northern Eritrea are discussed in the context of accretionary tectonics. The recognition of major north-south structural discontinuities allows the area to be divided into three discrete terranes with apparently different histories of deformation and metamorphism, magmagenesis and sedimentation. The central Hagar Terrane is dominated by large ultramafic masses with a volcano-sedimentary layered sequence, and shows the effects of major sinistral transpression and lateral expulsion. It is bounded to the west by a major fault, the Barka suture, and abuts the older Barka Terrane that comprises metasediments with evidence for polyphase ductile deformation and pre-kinematic dyke emplacement. The Hagar Terrane is thrust against the eastern Nacfa Terrane, which is dominated by low-grade calc-alkaline metavolcanics and immature volcanoclastic sediments intruded by syn-kinematic plutons. These units are pre-dated by an earlier high-grade basement and post-dated by high-level unmetamorphosed silicic volcanics and redbed sediments. The complex is suggested to have been assembled by oblique accretion from the southeast after arc volcanism in the Nacfa Terrane and back-arc extension in the Hagar Terrane ended with the cease of subduction.

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Delteil, Jean, Jean-François Stephan e Mikaël Attal. "Control of Permian and Triassic faults on Alpine basement deformation in the Argentera massif (external southern French Alps)". Bulletin de la Société Géologique de France 174, n. 5 (1 settembre 2003): 481–96. http://dx.doi.org/10.2113/174.5.481.

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Abstract Structural investigations reveal intense and heterogeneous deformation of the sedimentary cover attached to the basement complex of the southern Argentera and Barrot massifs (southernmost External Basement Massifs of the French Alps). Permian and early Triassic syn-depositional extensional tectonics imparted a tilted block pattern to the massifs. An early Miocene first stage of Alpine compression caused pervasive cleavage. This cleavage was controlled by the former pre-existing faults but is nevertheless consistent with NNE contraction. Where regional shortening is orthogonal to the trend of pre-existing faults the pervasive deformation produced either irrotational compressional strain (where no fault inversion occurred), or rotational compressional strain involving syn-cleavage shearing (where faults with favorable paleo-dip were inverted). Where the shortening direction is oblique to the paleo-fault trends, a component of strike-slip movement may locally prevail. A 22 %, N020o directed horizontal shortening, of 11 km, has been calculated based on deformed sedimentary markers in the Permian series and parallel folds in Lower Triassic quartzite. A shallower deformation as brittle reverse faults postdates the cleavage at the southwestern tip of the Argentera Massif and accounts for 4 km of extra shortening. Both types of deformation are connected at depth to a crustal blind thrust system and the Argentera Massif is over-thrust to the south-southwest. The observed strain indicates the Argentera Massif area underwent, from earliest Miocene to Present, a NNE to N rotating compression at distance from the left-lateral southwestern boundary of the Adria block.

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GÜRBÜZ, KEMAL. "Regional implications of structural and eustatic controls in the evolution of submarine fans: an example from the Miocene Adana Basin, southern Turkey". Geological Magazine 136, n. 3 (maggio 1999): 311–19. http://dx.doi.org/10.1017/s0016756899002617.

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Deep-sea fan development is generally thought to be controlled by a combination of changes in sea level, the shape and size of the basin in which the fans are growing, and the nature of the source area. The Early Miocene evolution of the eastern Mediterranean involved significant accumulation of deep-water clastic sediment in which the importance of each of these controlling factors can be evaluated. The deep-water clastic system located in the Adana Basin has been studied in detail. Two contemporaneous, small, radial, sand-rich submarine fans (one in the west and one in the east) exhibiting different scales, fan types and styles of deposition have been recognized within the Cingöz turbidite sequence of the northern Adana Basin in southern Turkey. Sedimentological studies indicate that the fans were controlled externally by tectonics and relative eustatic sea-level fall during late Serravallian time, in combination with the nature of the source area to the north. The internal architectural stacking patterns and external geometry of the two fan systems were strongly affected by the interaction of local tectonics and turbidity current pathways, including a major topographic confinement to the southeast that forced a vertical aggradation of the eastern fan and an east–west elongation of the western fan. This paper describes a classic example of a well-exposed deep-water clastic system where (1) tectonically driven sea-floor topography, (2) syn-sedimentary tectonism and (3) eustatic rise in sea level, are the primary controls on its development.

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Hughes, G. Wyn, David J. Grainger, Abdul-Jaleel Abu-Bshait e M. Jarad Abdul-Rahman. "Lithostratigraphy and Depositional History of Part of the Midyan Region, Northwestern Saudi Arabia". GeoArabia 4, n. 4 (1 ottobre 1999): 503–42. http://dx.doi.org/10.2113/geoarabia0404503.

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ABSTRACT The Midyan region provides a unique opportunity in which to examine exposures of the Upper Cretaceous and Neogene sedimentary succession. Recent investigations have yielded new interpretations of its depositional environments, stratigraphic relationships, and structure. In this paper, all the lithostratigraphic units of the Midyan succession are considered to be informal in advance of an on-going process of formalization. The region is bounded to the north and northeast by mountains of Proterozoic rocks and to the west and south by the Gulf of Aqaba and the Red Sea, respectively. The Wadi Ifal plain occupies most of the eastern half of the region, beneath which is a thick sedimentary succession within the Ifal basin. The oldest sedimentary rocks are the fluviatile Upper Cretaceous Adaffa formation and marine siliciclastics and carbonates of the lower Miocene Tayran group, unconformable on the Proterozoic basement. The Tayran group is unconformably overlain by the deep-marine lower Miocene Burqan formation that, in turn, is overlain by marine mudstones, carbonates, and evaporites of the middle Miocene Maqna group. The poorly exposed middle Miocene Mansiyah and middle to upper Miocene Ghawwas formations consist of marine evaporites and shallow to marginal marine sediments, respectively. The youngest rocks are alluvial sands and gravels of the Pliocene Lisan formation. A complex structural history is due to Red Sea Oligocene-Miocene extension tectonics, and Pliocene-Recent anti-clockwise rotation of the Arabian Plate relative to Africa on the Dead Sea Transform Fault. The Upper Cretaceous succession is a probable pre-rift unit. The Oligocene?-Miocene syn-rift 1 phase of continental extension caused slow subsidence (Tayran group). Syn-rift 2 was an early Miocene phase of rapid subsidence (Burqan formation) whereas syn-rift 3 (early to middle Miocene) was another phase of slow deposition (Maqna group). The middle to late Miocene syn-rift 4 phase coincided with the deposition of the Mansiyah and Ghawwas formations. The Lower Pliocene to Recent succession is related to the drift (post-rift) phase during which about 45 kilometers of sinistral movement occurred on the Dead Sea Fault. The structural control on sedimentation is evident: the Ifal basin was formed by east-west lithospheric extension; pull-apart basins occur along major left-lateral faults on the eastern coast of the Gulf of Aqaba; and basin-bounding faults controlled deposition of the Burqan, Ghawwas, and Lisan formations. Pliocene to Recent earth movements may be responsible for activating salt diapirism in the Ifal basin. Extensive Quaternary faulting and regional uplift caused the uplift of coral reefs to at least 6 to 8 meters above sea level.

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Petrik, Attila, Barbara Beke, László Fodor e Réka Lukács. "Cenozoic structural evolution of the southwestern Bükk Mts. and the southern part of the Darnó Deformation Belt (NE Hungary)". Geologica Carpathica 67, n. 1 (1 febbraio 2016): 83–104. http://dx.doi.org/10.1515/geoca-2016-0005.

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Abstract Extensive structural field observations and seismic interpretation allowed us to delineate 7 deformation phases in the study area for the Cenozoic period. Phase D1 indicates NW–SE compression and perpendicular extension in the Late Oligocene–early Eggenburgian and it was responsible for the development of a wedge-shaped Paleogene sequence in front of north-westward propagating blind reverse faults. D2 is represented by E–W compression and perpendicular extension in the middle Eggenburgian–early Ottnangian. The D1 and D2 phases resulted in the erosion of Paleogene suites on elevated highs. Phase D2 was followed by a counterclockwise rotation, described in earlier publications. When considering the age of sediments deformed by the syn-sedimentary D3 deformation and preliminary geochronological ages of deformed volcanites the time of the first CCW rotation can be shifted slightly younger (~17–16.5 Ma) than previously thought (18.5–17.5 Ma). Another consequence of our new timing is that the extrusional tectonics of the ALCAPA unit, the D2 local phase, could also terminate somewhat later by 1 Myr. D4 shows NE–SW extension in the late Karpatian–Early Badenian creating NW–SE trending normal faults which connected the major NNE–SSW trending sinistral faults. The D5 and D6 phases are late syn-rift deformations indicating E–W extension and NW–SE extension, respectively. D5 indicates syn-sedimentary deformation in the Middle Badenian–early Sarmatian and caused the synsedimentary thickening of mid-Miocene suites along NNE–SSW trending transtensional faults. D5 postdates the second CCW rotation which can be bracketed between ~16–15 Ma. This timing is somewhat older than previously considered and is based on new geochronological dates of pyroclastite rocks which were not deformed by this phase. D6 was responsible for further deepening of half-grabens during the Sarmatian. D7 is post-tilt NNW–SSE extension and induced the deposition of the 700 m thick Pannonian wedge between 11.6–8.92 Ma in the southern part of the study area.

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Cherchi, Antonietta, Nicoletta Mancin, Lucien Montadert, Marco Murru, Maria Teresa Putzu, Francesco Schiavinotto e Vladimiro Verrubbi. "The stratigraphic response to the Oligo-Miocene extension in the western Mediterranean from observations on the Sardinia graben system (Italy)". Bulletin de la Société Géologique de France 179, n. 3 (1 maggio 2008): 267–87. http://dx.doi.org/10.2113/gssgfbull.179.3.267.

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Abstract The Sardinian Cainozoic rifted basin is a useful model for studying the stratigraphic response to the Oligo-Miocene structural extension in the western Mediterranean because it allows precise observations on the relationship between sedimentation and normal faulting based on outcrops and seismic reflection data. The purpose of this paper, essentially of stratigraphic nature is to propose a chronology as precise as possible of the tectonic events and of the sedimentary formations. Indeed the tectono-sedimentary framework is complex, characterized by an extreme facies variability, from continental to marginal transitional and to marine environments (shallow-water, hemipelagic). Rifting, active calc-alkaline volcanism and sea-level changes caused rapid physiographical evolution, which controlled progressive marine ingression. New chronobiostratigraphical data presented in this paper allow correlating the sequences, defining their environment and depth of deposition and specifying precisely the timing of pre-, syn-, and post-rift stages in the Oligo-Miocene graben system. In southwestern Sardinia during the middle-late Eocene, after the Pyrenean phase, a continental graben (Cixerri), W-E oriented, preceded the Oligo-Miocene extension, which reactivated inherited Eocene and Palaeozoic faults. The calc-alkaline volcanic activity ranging from 32 to 13 Ma, provides a good estimate for the time span of the west-dipping Apenninic subduction responsible for the continental extension and the oceanic accretion in the western Mediterranean. In Sardinia the Oligo-Miocene extensional tectonics started in a continental environment, preceding the earliest calc-alkaline volcanic products (32 Ma). The marine ingression is dated to the late Chattian-Aquitanian interval and corresponds to a rapid deepening of the Oligo-Miocene graben system of tectonic origin. The end of the rifting i.e. the end of normal faulting activity is pre-middle Burdigalian in age. When Sardinia was in the post-rift stage, extension continued until late Burdigalian – Langhian in the Algero-Provençal basin with oceanic accretion and rotation of the Corsica-Sardinia block (CSB).

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19

Gregersen, Ulrik, Paul C. Knutz, Henrik Nøhr-Hansen, Emma Sheldon e John R. Hopper. "Tectonostratigraphy and evolution of the West Greenland continental margin". Bulletin of the Geological Society of Denmark 67 (27 luglio 2020): 1–21. http://dx.doi.org/10.37570/bgsd-2019-67-01.

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Large structural highs and sedimentary basins are identified from mapping of the West Greenland continental margin from the Labrador Sea to the Baffin Bay. We present a new tectonic elements map and a map of thickness from the seabed to the basement of the entire West Greenland margin. In addition, a new stratigraphic scheme of the main lithologies and tectonostratigraphy based on ties to all offshore exploration wells is presented together with seven interpreted seismic sections. The work is based on interpretation of more than 135 000 km of 2D seismic reflection data supported by other geophysical data, including gravity- and magnetic data and selected 3D seismic data, and is constrained by correlation to wells and seabed samples. Eight seismic mega-units (A–H) from the seabed to the basement, related to distinct tectonostratigraphic phases, were mapped. The oldest units include pre-rift basins that contain Proterozoic and Palaeozoic successions. Cretaceous syn-rift phases are characterised by development of large extensional fault blocks and basins with wedge-shaped units. The basin strata include Cretaceous and Palaeogene claystones, sandstones and conglomerates. During the latest Cretaceous, Paleocene and Eocene, crustal extension followed by oceanic crust formation took place, causing separation of the continental margins of Greenland and Canada with north-east to northward movement of Greenland. From Paleocene to Eocene, volcanic rocks dominated the central West Greenland continental margin and covered the Cretaceous basins. Development of the oceanic crust is associated with compressional tectonics and the development of strike-slip and thrust faults, pull-apart basins and inversion structures, most pronounced in the Davis Strait and Baffin Bay regions. During the late Cenozoic, tectonism diminished, though some intra-plate vertical adjustments occurred. The latest basin development was characterised by formation of thick Neogene to Quaternary marine successions including contourite drifts and glacial related shelf progradation towards the west and south-west.

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20

Wulff, Keiran. "DEPOSITIONAL HISTORY AND FACIES ANALYSIS OF THE UPPER JURASSIC SEDIMENTS IN THE EASTERN BARROW SUB-BASIN". APPEA Journal 32, n. 1 (1992): 104. http://dx.doi.org/10.1071/aj91010.

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Callovian to Tithonian syn-rift sediments in the eastern Barrow Sub-basin can be subdivided into five depositional sequences, each separated by regionally correlatable unconformities. Sequence boundary development can be closely related to periods of major changes in basin configuration associated with the sequential breakup of eastern Gondwanaland. Synchronism of major faulting with sequence boundary development during the early and late Callovian, mid Kimmeridgian, and mid Tithonian times supports tectonism being a dominant control on the development of Type 1 unconformities in the eastern Barrow Sub-basin.Upper Jurassic depositional sequences in the eastern Barrow Sub-basin, whether of tectonic or eustatic origin, consist primarily of lowstand systems tracts comprised, wholly or in part, of detached basin floor fan complexes, channelised and canyon-fed fan systems, slump deposits, outer shelf to slope deposits, and deep marine claystones. Inner shelf to shoreface sediments of the transgressive and highstand systems tracts are absent due to episodic, post-depositional uplift and erosion along the Peedamullah Shelf and Flinders Fault System during the Late Jurassic. The periods of uplift and erosion provided much of the sediment redeposited in basinal areas during lowstand times.Depositional models based on regional sequence stratigraphic studies can be integrated with local seismic stratigraphy to provide a mechanism for estimating likely reservoir quality, once controls on sedimentation (namely tectonics, eustasy, and sediment supply) are understood. This is demonstrated by the recognition of at least seven sandstone facies within the Upper Jurassic sedimentary section. Each sandstone has particular characteristics which can be related to the depositional setting. Reservoir quality is best developed in dominantly medium grained, moderate to well sorted sandstones, deposited as detached, basin floor submarine fan sands or interbedded turbidites. In contrast, reservoir quality is poorly developed in the remaining sand-prone facies deposited as slope fans, slumps, or distal turbidites.

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21

Cipriani, Angelo, e Cinzia Bottini. "Unconformities, neptunian dykes and mass-transport deposits as an evidence for Early Cretaceous syn-sedimentary tectonics: new insights from the Central Apennines". Italian Journal of Geosciences 138, n. 3 (ottobre 2019): 333–54. http://dx.doi.org/10.3301/ijg.2019.09.

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22

Hunt, Julie A., Tim Baker, James Cleverley, Garry J. Davidson, Anthony E. Fallick e Derek J. Thorkelson. "Fluid inclusion and stable isotope constraints on the origin of Wernecke Breccia and associated iron oxide – copper – gold mineralization, Yukon". Canadian Journal of Earth Sciences 48, n. 10 (ottobre 2011): 1425–45. http://dx.doi.org/10.1139/e11-044.

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Iron oxide – Cu ± Au ± U ± Co (IOCG) mineralization is associated with numerous Proterozoic breccia bodies, collectively known as Wernecke Breccia, in Yukon Territory, Canada. Multiphase breccia zones occur in areas underlain by Paleoproterozoic Wernecke Supergroup metasedimentary rocks and are associated with widespread sodic, potassic, and carbonate alteration assemblages. Fluid inclusion data indicate syn-breccia fluids were hot (185–350 °C) saline (24–42 wt.% NaCl equivalent) NaCl–CaCl2–H2O brines. Estimates of fluid pressure vary from 0.4 to 2.4 kbar (1 kbar = 100 MPa). Carbon and oxygen isotopic compositions of breccia-related carbonates range from ~–11‰ to +1.5‰ (Pee Dee belemnite (PDB)) and –2‰ to 20‰ (Vienna standard mean ocean water (V-SMOW); δ18Owater ~–8‰ to +15‰), respectively. δ13C and δ18O values for host Wernecke Supergroup limestone/dolostone vary from ~–2‰ to 1.6‰ and 12‰ to 25‰, respectively. Sulfur isotopic compositions of hydrothermal sulfides and sulfate vary from ~–12‰ to +13‰ and +8‰ to +17‰ (Cañon Diablo Troilite (CDT)), respectively. Syn-breccia biotite, muscovite, and actinolite have δD and δ18O values of ~–141‰ to –18‰ and +7‰ to +12‰ (V-SMOW; δ18Owater ~7‰ to 11‰), respectively. The Wernecke Breccias and the associated IOCG mineralization appear to have formed from largely nonmagmatic fluids — based on isotopic, fluid inclusion, and geological data. The emerging hypothesis is that periodic overpressuring of dominantly formational/metamorphic water led to repeated brecciation and mineral precipitation. The weight of overlying sedimentary rocks led to elevated fluid temperatures and pressures; fluid flow may have been driven by tectonics and (or) gravity with metals scavenged from host strata.

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Bramham, Emma K., Tim J. Wright, Douglas A. Paton e David M. Hodgson. "A new model for the growth of normal faults developed above pre-existing structures". Geology 49, n. 5 (26 gennaio 2021): 587–91. http://dx.doi.org/10.1130/g48290.1.

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Abstract Constraining the mechanisms of normal fault growth is essential for understanding extensional tectonics. Fault growth kinematics remain debated, mainly because the very earliest phase of deformation through recent syn-kinematic deposits is rarely documented. To understand how underlying structures influence surface faulting, we examined fault growth in a 10 ka magmatically resurfaced region of the Krafla fissure swarm, Iceland. We used a high-resolution (0.5 m) digital elevation model derived from airborne lidar to measure 775 fault profiles with lengths ranging from 0.015 to 2 km. For each fault, we measured the ratio of maximum vertical displacement to length (Dmax/L) and any nondisplaced portions of the fault. We observe that many shorter faults (<200 m) retain fissure-like features, with no vertical displacement for substantial parts of their displacement profiles. Typically, longer faults (>200 m) are vertically displaced along most of their surface length and have Dmax/L at the upper end of the global population for comparable lengths. We hypothesize that faults initiate at the surface as fissure-like fractures in resurfaced material as a result of flexural stresses caused by displacements on underlying faults. Faults then accrue vertical displacement following a constant-length model, and grow by dip and strike linkage or lengthening when they reach a bell-shaped displacement-length profile. This hybrid growth mechanism is repeated with deposition of each subsequent syn-kinematic layer, resulting in a remarkably wide distribution of Dmax/L. Our results capture a specific early period in the fault slip-deposition cycle in a volcanic setting that may be applicable to fault growth in sedimentary basins.

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Casabianca, Davide, Antoine Auzemery, Andrea Barrier, Angelo Ricciato, Stefano Borello, Alice Lecardez e Raffaele Di Cuia. "Latest fold and thrust tectonics conceals extensional structures inherited from Cretaceous syn-sedimentary deformation: insights for exploration in fold-and-thrust belts from the Maiella Mountain". Geological Society, London, Special Publications 490, n. 1 (2020): 241–66. http://dx.doi.org/10.1144/sp490-2019-9.

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25

Dreesen, Roland, Dominique Bossiroy, Michiel Dusar, Romeo M. Flores e Paul Verkaeren. "Overview of the influence of syn-sedimentary tectonics and palaeo-fluvial systems on coal seam and sand body characteristics in the Westphalian C strata, Campine Basin, Belgium". Geological Society, London, Special Publications 82, n. 1 (1995): 215–32. http://dx.doi.org/10.1144/gsl.sp.1995.082.01.15.

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26

Minguely, Bruno, Olivier Averbuch, Marie Patin, David Rolin, Franck Hanot e Francoise Bergerat. "Inversion tectonics at the northern margin of the Paris basin (northern France): new evidence from seismic profiles and boreholes interpolation in the Artois area". Bulletin de la Société Géologique de France 181, n. 5 (1 settembre 2010): 429–42. http://dx.doi.org/10.2113/gssgfbull.181.5.429.

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AbstractA synthesis of existing borehole data and seismic profiles has been conducted in the Artois area (northern France), along the northern border of the Paris basin, in order to explore the possible control exerted at depth by the Upper Carboniferous Variscan thrust front on the distribution of Late Paleozoic-Mesozoic depositional centers and their subsequent uplift in Tertiary times. Such control was demonstrated recently in the Weald-Boulonnais basin (Eastern Channel area) that forms the western prolongation of the area under study but was so far poorly constrained in the Artois area. Presented data provide evidence for the topography of the Artois hills and the altitude of sedimentary layers to be controlled by the activity of a network of relaying WNW-ESE striking faults inducing the systematic uplift of the southern fault blocks. Those steeply S-dipping faults branch downward onto the ramp of the Variscan thrusts forming listric faults that locally limit to the north buried half-graben structures, filled with fan-shaped fluviatile Stephanian-Permian deposits. Such clear syn-rift geometry shows that the ramp of the main Variscan frontal thrust (the Midi thrust) has been reactivated as a normal fault in Stephanian-Permian times thus forming a very demonstrative example of a negative inversion process. The reverse offset of the transgressive Middle Cretaceous-Lower Eocene layers covering unconformably the Paleozoic substratum argue for a Tertiary (Middle Eocene-Late Oligocene?) contractional reactivation of the fault network thereby documenting a repeated inversion process along the Artois Variscan thrust front. The Variscan frontal thrust zone is thus shown here to represent a prominent crustal-scale mechanical discontinuity that localized deformation in the Artois-Boulonnais area since Upper Paleozoic times.

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Ge, Zhiyuan, Matthias Rosenau, Michael Warsitzka e Rob L. Gawthorpe. "Overprinting translational domains in passive margin salt basins: insights from analogue modelling". Solid Earth 10, n. 4 (2 agosto 2019): 1283–300. http://dx.doi.org/10.5194/se-10-1283-2019.

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Abstract. Current models of gravitational tectonics on the structural styles of salt-influenced passive margins typically depict domains of upslope extension and corresponding downslope contraction separated by a mid-slope domain of translation that is rather undeformed. However, an undeformed translational domain is rarely observed in natural systems as extensional and contractional structures tend to interfere in the mid-slope area. In this study, we use sandbox analogue modelling analysed by digital image correlation (DIC) to investigate some of the factors that control the structural evolution of translational domains. As in nature, experimental deformation is driven by slowly increasing gravitational forces associated with continuous basal tilting. The results show that a translational domain persists throughout the basin evolution when the pre-kinematic layer is evenly distributed. However, a thin (1 mm in the experiment, 100 m in nature) pre-kinematic layer can render the translational domain relatively narrow compared to settings with a thicker (5 mm) pre-kinematic layer. In contrast, early differential sedimentary loading in the mid-slope area creates minibasins separated by salt diapirs overprinting the translational domain. Similarly, very low sedimentation rate (1 mm per day in the experiment, < 17 m Ma−1 in nature) in the early stage of the experiment results in a translational domain quickly overprinted by downslope migration of the extensional domain and upslope migration of the contractional domain. Our study suggests that the architecture of passive margin salt basins is closely linked to the pre- and syn-kinematic cover thickness. The translational domain, as an undeformed region in the supra-salt cover, is a transient feature and overprinted in passive margins with either low sedimentation rate or a heterogeneous sedimentation pattern.

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Tubbs, Robert E., Hussein G. Aly Fouda, Abdulkader M. Afifi, Nickolas S. Raterman, Geraint W. Hughes e Yousuf K. Fadolalkarem. "Midyan Peninsula, northern Red Sea, Saudi Arabia: Seismic imaging and regional interpretation". GeoArabia 19, n. 3 (1 luglio 2014): 165–84. http://dx.doi.org/10.2113/geoarabia1903165.

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ABSTRACT The Midyan Peninsula of northwest Saudi Arabia offers an exceptional opportunity to observe a complex interplay of rifting, salt tectonics, and strike-slip faulting. Recently onshore 3-D, transition zone 2-D, and offshore 2-D seismic data have been acquired in the area. In addition, ongoing fieldwork and an active drilling program have provided new insights into the geologic history of the region. The initial stages of continental rifting began during the Early Oligocene (ca. 33 Ma) and often utilized pre-existing basement fault trends. The early syn-rift sedimentary record is typified by formation of deep half-grabens filled with thick wedges of primarily continental sediments, with lesser amounts of evaporitic and marine deposits. Seismic data show a distinct break in deposition occurred ca. 21 Ma characterized by a persistent angular unconformity near the basin-bounding fault, before a shift to marine and offshore deposits of the Lower Miocene Burqan Formation. Post-Burqan a second angular unconformity termed the mid-clysmic event is evident away from the basin edge. This surface exhibits significant relief created by re-activation of older EW-trending faults and lower Maqna Group sediments display substantial thickening across these faults. Overall, the Maqna section transitions from normal marine sedimentation to more restricted basin conditions before being succeeded by the thick-layered evaporite sequence of the Mansiyah Formation. Approximately 15–12 Ma active strike-slip faults appeared in the Red Sea and shifted the extension from rift normal to highly oblique directed at N15°–20°E, parallel to the Gulf of Aqaba. During this transition the composition of the rift-fill changed as well from basin-wide precipitates to thick siliciclastic wedges of the Ghawwas Formation. Seismic images of the Ghawwas show abrupt thickness changes and stratal geometries that date deposition as coincident with both the growth of Mansiyah Formation diapirs and the movement of a large detachment at the base of the Mansiyah. Roughly five million years ago, organized seafloor spreading began in the southern Red Sea and strike-slip motion intensified as deformation began to focus along the Dead Sea/Aqaba strike-slip fault system. Adjacent to Midyan, a pull-apart basin in the Gulf of Aqaba has opened over 26 km perpendicular to the strike-slip system resulting in significant footwall uplift. The positive interference of the Aqaba/Dead Sea and Red Sea footwall uplifts has uniquely exposed the full syn-rift stratigraphic section from basement to Upper Miocene at Midyan, making the area an ideal locality for field studies. Presence of the complete Miocene section on the Aqaba shoulder uplift clearly indicates the uplift occurred after the Miocene. Salt-filled pull-apart basins in the same orientation as the Gulf of Aqaba are also observed on 3-D seismic data in the Ifal Basin.

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Alonso, J. L., E. Barrón, B. González Fernández, E. Menéndez Casares e J. C. García-Ramos. "Extensión e inversión tectónica alpinas en el área de Sariego. Control ejercido por la estructura varisca subyacente (Asturias, norte de España) Alpine extension and inversion tectonics in the Sariego area. Control exerted by the underlying Variscan structure (Asturias, northern Spain)". Trabajos de Geología 36, n. 36 (12 settembre 2018): 45. http://dx.doi.org/10.17811/tdg.36.2016.45-60.

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Resumen: Dos de las fallas mayores de rumbo E-O, que afectan a la cuenca pérmico-mesozoica asturiana (Fallas de Llanera y Careses), pasan por el área de Sariego. Un afloramiento de gran interés pedagógico situado en el talud de la autovía del Cantábrico, cerca de la localidad de Lamasanti, ilustra muy bien el significado de la Falla de Llanera. Dicha falla jugó como falla normal durante el Jurásico Superior y parte más baja del Cretácico Inferior y como falla inversa durante la orogenia Alpina. Su desplazamiento normal fue mayor que el inverso, observándose el punto nulo en el afloramiento mencionado. En ese mismo afloramiento se ha datado con polen la base de la secuencia post-rift del bloque inferior de la falla, obteniéndose una edad Barremiense, siendo la primera vez que se registra este piso en la cuenca mesozoica asturiana. Respecto a la Falla de Careses, se muestra en su sector oriental como una falla normal invertida. Sin embargo, en su sector occidental es una falla inversa que puede interpretarse como una falla de atajo de la falla normal mencionada; el juego inverso de esta falla se refleja en el relieve actual dando lugar a un escarpe mucho más notable que el de la Falla de Llanera. Las dos fallas mayores mencionadas se encuentran cortadas por otras de rumbo SO-NE que representan la reactivación de las estructuras variscas subyacentes durante la orogenia alpina, jugando probablemente en transpresión, como fallas de desgarre con ligero movimiento inverso, generando pliegues subparalelos a las mismas. No obstante, existen evidencias de que estas estructuras variscas se reactivaron previamente como fallas normales, controlando los espesores de la sucesión pérmica. La edad relativa de los diferentes sistemas de fallas durante el acortamiento alpino es la siguiente: primero actuaron las fallas de Llanera y Careses, despúes las de rumbo NE-SO y por último actuó la Falla de Ventaniella, que trunca a todas ellas.Palabras clave: inversión tectónica, punto nulo, estructuras de basamento reactivadas, Barremiense, palinomorfos, Cuenca Asturiana.Abstract: Two major structures involving the Permian-Mesozoic Asturian Basin (Llanera and Careses faults) are analysed in the Sariego area. The Llanera Fault played as a syn-sedimentary normal fault during the Upper Jurassic-lowermost Cretaceous and was inverted in Cenozoic times. Its reverse displacement was lower than the previous normal displacement and the null point is exposed in an illustrative outcrop located near the Lamasanti village, in the lateral talus of the Cantabrian motorway (A64-E70). In this outcrop, sampling was carried out at the base of postrift succession, in order to obtain palynomorphs, which have provided a Barremian age. This stage has not been recorded in the Asturian Basin so far. The Careses Fault is mainly a reverse fault and is responsible for the major relief of the study area; however, the eastern part of this fault can be recognized as an inverted normal fault, whereas its western part can be interpreted as a short cut thrust of that normal fault. Both, the Llanera and Careses faults are truncated by several SWNE trending faults, which mean the reactivation of buried variscan structures during the Alpine deformation. The map pattern of these SW-NE trending faults implies an oblique displacement, composed of strike and vertical slip; however, these faults played previously as syn-rift extensional faults in Permian times, as recorded by thickness changes in the Permian succession.Keywords: tectonic inversion, null point, inherited basement structures, Barremian, palynomorphs, Asturian Basin.

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Kosun, Erdal, André Poisson, Attila Çiner, Roland Wernli e Olivier Monod. "Syn-tectonic sedimentary evolution of the Miocene Çatallar Basin, southwestern Turkey". Journal of Asian Earth Sciences 34, n. 3 (marzo 2009): 466–79. http://dx.doi.org/10.1016/j.jseaes.2008.07.005.

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Laumonier, Bernard, Christian Marignac e Philippe Kister. "Polymetamorphism and crustal evolution of the eastern Pyrenees during the Late Carboniferous Variscan orogenesis". Bulletin de la Société Géologique de France 181, n. 5 (1 settembre 2010): 411–28. http://dx.doi.org/10.2113/gssgfbull.181.5.411.

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Abstract (sommario):

AbstractAbridged English version. – The Variscan Pyrenean belt (fig. 1) has been for long famous for its Late Carboniferous LP-HT metamorphism, characterised by the prograde succession, in medium grade metapelites, of biotite, cordierite, andalusite and sillimanite, together with staurolite and garnet [Guitard et al., 1996]. However, the discovery of two kyanite generations lead Azambre and Guitard [2001] to propose a polymetamorphic evolution, with an early (MI) and a late (MIII) kyanite-bearing Barrovian stage, preceding and following the main LP-HT stage (MII).Geological settingThe Variscan orogeny in the Pyrenees occurred from Namurian to Early Stephanian (c. 325-300 Ma), following the deposition of thick Ediacarian-Ordovician silico-clastites, Silurian to Early Caboniferous carbonates, and pre-orogenic Mid-Carboniferous flyschs.Two main tectonic events are recorded, each one subdivided into regionally correlated sub-events (phases) (table I), allowing a detailed correlation between tectonics, metamorphism and plutonism. The Namurian to Westphalian D1 event (c. 325-310 Ma) resulted in a S-vergent fold and thrust belt (with 100–150 km of N-S shortening) and the development of the main, sub-horizontal, Sr schistosity (D1c phase), coeval with MI. The Westphalian-Early Stephanian D2 event (310-300 Ma) was more complex. First, a syn-convergence extensional phase (N-vergent backfolds and E-W extension) resulted in the E-directed escape of the upper crust (D2a phase). Then, a renewal of the N-S shortening was marked by large upright anticlines (domes) and narrower synclines, with up to 10 km amplitudes (e.g., the Canigou anticline-Villefranche syncline pair) (D2b phase). Both D2a and D2b were coeval with MII and the emplacement of early granitoid sills and laccoliths (e.g., the Ansignan hypersthene-granite in the Agly Massif). Later on, D2 evolved into a transcurrent regime, with belt-parallel dextral transpression (D2c and D2c phases). D2c was coeval with the main stage of granite emplacement under low-grade conditions, allowing the expression of a conspicuous Mγ contact metamorphism (e.g., Mont-Louis pluton). D2d ended the D2 event, with the development of retrograde dextral-reverse mylonites. The late MIII metamorphic event encompassed D2c and D2d (and possibly D2b).The early MI Barrovian metamorphic eventThe MI Barrovian metamorphic event resulted from the crustal thickening associated with the development of the D1 intra-cratonic wedge. It was of low-grade, with a chlorite-muscovite Sr schistosity, in the part of the belt that was subsequently overprinted by the syn-MII transformation of chlorite into biotite. The only remnants of MI medium-grade conditions are found as early kyanite in the deepest domains of the Castillon, St-Barthélémy, Agly and Aston massifs, being there obliterated under high-grade MII conditions, and in the core of the Canigou anticline (Velmanya, point v in fig. 2), where a relict kyanite-staurolite-anorthite paragenesis is known, shielded by MII cordierite. The reconstructed P-T conditions at the thermal peak of MI are 5 kbar (19 km) and 575oC (fig. 2), implying the existence of a (now eroded) major D1 nappe (≥ 7 km thick).The main MII LP-HT metamorphic eventStructural domes and medium– or high-grade MII zones are broadly coincident, high-grade conditions being only encountered in the core of the Albères massif, the southern Aston Dome and the North-Pyrenean massifs (grading there up to the LP granulite facies) (fig. 1).Subdivisions of the MII eventThe prograde MII metamorphism is essentially syn-D2a, with clear syn-kinematic growth of the medium-grade minerals, and the main regional tectono-metamorphic D2a/MII structure is evidently deformed and strongly folded by the D2b phase: the D2b domes are basically post-metamorphic. However, a detailed examination of the blastesis-deformation relationships shows that staurolite is pre- to-synkinematic for D2a, whereas andalusite is strictly synkinematic (and consequently is often observed shielding the staurolite), cordierite being syn-to post-kinematic and syn-D2b in some instances. This allows a subdivision of the MII event into three stages:– MIIs, pre-to-syn-D2a, characterised by the staurolite-andalusite (And1 without cordierite) association, with development of a staurolite zone grading downwards into an andalusite (St → And1) zone. – MIIa, syn-to post-D2a (but always developed prior to D2b), characterised by the cordierite (Cord1)-andalusite (And2) association (without staurolite), with development of a thin cordierite zone grading downwards into an andalusite (Cord1 → And2) zone. – MIIb, post-D2a and syn-D2b, characterised by a large cordierite (Cord2) zone developed at the expense of an-dalusite (And → Cord2), only found in the core of the D2b anticlines (e.g., the Garonne dome).Thus, although MII is basically pre-D2b, and the MIIs and MIIa medium-grade isogrades are folded, it appears that metamorphism was still active in the cores of the ascending D2b domes (MIIb). Moreover, in the core of some domes, prograde sillimanite is also syn-kinematic of the D2b phase, and the sillimanite-muscovite isograde may obliquely overprint the MIIa isogrades, as in the Canigou dome. This is related to the syn-D2b emplacement of granite sheets (e.g., the Canigou granite) and may be interpreted as an aureola of “regional-contact” metamorphism, noted MIIγ, that was evidently coeval with MIIb, and enhanced its effects.P-T-t path of the MII eventThe P-T-t path of the MII event may be described using the petrogenetic grids of Pattison et al. [2002] and Pattison and Vogl [2005] (fig. 3). From MIIs to MIIb, it records a prograde anti-clockwise path, following a post-MI clockwise exhumation path, with ≥ 7 km eroded (fig. 2B). The MIIs pressure was close to 3 kbar (10–11 km) in the St zone and decreased to 2.5 kbar (9 km) at the MIIa stage (And2 isograde), for an estimated temperature of 540oC (based on the triple point of Holdaway [1971], the thermobarometer of Pattison et al. [2002] and independent fluid inclusion data by Kister et al. [2003]). A further pressure decrease, down to 2 kbar (7 km), and a temperature increase (up to 600oC) is registered in the MIIb cordierite zone in the core of active D2b domes. Except for the cores of the domes, MIIa remained the peak temperature event, and during MIIb pressure remained constant (or was re-increasing in the syncline cores) and temperature was constant or decreasing. At the end of the MII event (MIIb-MIIγ), extreme conditions of c. 4 kbar and 700–730oC are recorded in the deepest parts of the belt, where anatexis, succeeding to a sillimanite-K-feldspar zone, is observed, as in the Albères Massif and some North-Pyrenean Massifs.The MII metamorphism as a syn-tectonic plutono-metamorphic eventBased on the observation of the deep crust outcropping in the North Pyrenean massifs, Vielzeuf [in Guitard et al., 1996] concluded that emplacement of mafic melts in the Carboniferous lower crust was responsible for the MII metamorphism. At the beginning of the process, a regional thermal anomaly is superimposed to the middle crust (MIIs-MIIa), directly reflecting the emplacement of mafic sills in the underlying lower crust (fig. 4A). Heat is transferred conductively and, most likely, advected by the aqueous-carbonic fluids issued from the devolatilising lower crust (fluid inclusion data). Heat advection by melts characterised the end of the MII event, with development of more or less local thermal anomalies: still “regional” (MIIbγ) as in the Garonne dome, or directly liked to sheet-like granite intrusions (MIIγ) as at the bottom of the Mont-Louis pluton (fig. 4B) or at the contact of the Canigou granite (fig. 4C).The late MIII Barrovian metamorphic eventThe MIII event is mainly characterised in the eastern massifs (Albères, Cap de Creus), where a retrogressive kyanite (so-called “hysterogenic” kyanite) is overprinting high-grade assemblages. Although poorly expressed, MIII minerals in these massifs define two zones, with an external chloritoid zone and an internal kyanite-staurolite zone. A MIII chloritoid zone (sillimanite → chloritoid) is also observed in the core of the Canigou dome. Under the kyanite-staurolite equilibrium hypothesis, the peak MIII P-T conditions in the eastern massifs are estimated at 5 kbar and 575oC, that would imply a pressure increase of 1 to 1.5 kbar (4–6 km deepening) starting from the end of MII, associated with a severe temperature decrease of 150oC. Such an overpressure cannot be due to the D2d dextral-inverse mylonites. However, a fluid inclusion study [Kister et al., 2003] demonstrated that the rocks of the Villefranche syncline did register a pressure increase at the D2b stage, i.e., experienced effective downwards displacement during the syncline formation, and it may be estimated that, in the core of the syncline, a depth increase of 7–8 km could have been attained. Now, in the Cap de Creus massif, the highest MIII grade is observed in the core of the D2b Birba syncline, analogous to the Villefranche syncline. Thus, D2b deepening in the syncline cores may have contributed to the pressure increase. An additional increase may have been provided by sedimentary accumulation in an overlying (and now eroded) syn-orogenic basin (fig. 5). While such a process may explain the development of MIII associations in the D2b synclines, it remains to explain its appearance in the anticlines (Albères, Canigou). However, in the same fluid inclusion study referred to just above [Kister et al., 2003], it is demonstrated that, post-dating D2c and the late pluton emplacement, the studied area suffered a severe isobaric temperature drop, allowing the appearance of chloritoid in the Canigou core (fig. 5). A similar explanation may hold for the Albères massif, if it is accepted there that late kyanite and staurolite were not in equilibrium: starting from the peak MII conditions (c. 4 kbar and 650o–700oC), a strong isobaric cooling would have allowed the successive appearance of staurolite and kyanite.Discussion and conclusionTimingThe youngest pre-orogenic flyschs are dated (in the Axial Zone) from the Namurian-Westphalian boundary (315±5 Ma), thus setting a minimal age for D1-MI. On the other hand, in the northern Pyrenean Agly massif, the Ansignan hypersthene-granite, which is coeval with MII, is dated at around 315-305 Ma, and the associated norites, likely testifying for the mafic magmatism at the origin of the heat flux responsible for MII, are themselves dated at c. 315 Ma. Finally, the large syn-D2c (post-MII) granite plutons are all dated at 307±3 Ma (i.e., close to the Westphalian-Stephanian boundary). Taken together (with the possibility of a slight diachronism between the North Pyrenean massifs and the Axial Zone, and, within the Axial Zone, between east and west), these data indicate that the MI-MII transition and the whole D2a–c/MII development took place in a very restricted time interval (c. 10 Ma), in Westphalian to Stephanian times.Crustal rheology and orogenic developmentAt the end of the Namurian crustal subduction (D1-MI), the Pyrenean crust, that had been thickened with at least a doubling of the upper crust thickness, had begun to experience uplift and erosion. This exhumation process rapidly changed from retrograde to prograde (MIIs-MIIa) during the D2a (MII) syn-convergence extensional phase.The D2a sub-event was marked by the development of three interrelated processes: (i) isotherm upwelling, regional stratiform MII metamorphism and partial melting in the middle crust, as a result from the intrusion, in the lower crust, of mafic magmas of mantellic derivation; (ii) thinning of the thickened crust; (iii) first arrival of granite plutons in the middle crust. It is thought, according to Vielzeuf [inGuitard et al., 1996], that these processes were initiated by a lithospheric delamination process.At the end of D2a, the crustal rheology had been modified, with a partially melted middle crust that received granitic melts issued from the melting of the lower crust. This highly ductile middle crust was sandwiched between a thick (≥ 10 km) rigid upper crust and a less ductile granulitised hot lower crust (800o–900oC), thus allowing the progressive decoupling of the upper and lower crust from D2a to D2c. The buckling of the upper crust, with formation of the large upright D2b folds, became therefore possible, forcing the injection of deep anatectic melts in the anticline cores (a probable explanation of the MIIbγ thermal culmination), and creating, in the deepened syncline cores, the strong pressure increase that favoured MIII inception.However, the MII isogrades are frozen in their folded position, indicating that cooling of the belt had indeed begun since at least the end of the D2b phase. The cooling was sufficiently rapid to be expressed in the Axial Zone by a sub-isobaric temperature decrease, at the origin of the MIII Barrovian and retrograde event, coeval with the late D2c and D2d phases. In the North Pyrenean Massifs, where the D2d phase was extensive, the retrograde MIII event could not be expressed, due to both decompression and thermal effects of the extension.A summary of this complex evolution is given in figure 6. Finally, the interrelated D2 and MII events appear as the record, in the middle-upper crust, of a very short, but very intense heating event that strongly modified the rheologic behaviour of the crust inherited from the D1 crustal subduction and allowed a transitory decoupling of the upper and lower crust. The isobaric MIII event records an exceptionally rapid return to the “normal” thermal and rheologic structures of the crust.The rapidly changing tectonic and thermal conditions that characterise the Variscan Pyrenees during the D2 event may be understood if the position of the Pyrenees within the southern branch of the West European Variscan belt is considered (fig. 7).

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Villalaín, Juan J., Antonio M. Casas-Sainz e Ruth Soto. "Reconstruction of inverted sedimentary basins from syn-tectonic remagnetizations. A methodological proposal". Geological Society, London, Special Publications 425, n. 1 (2 ottobre 2015): 233–46. http://dx.doi.org/10.1144/sp425.10.

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O. Oluyede, Kehinde. "Alkaline rocks of the northern part of Birnin Gwari schist belts, northwestern Nigeria: provenance and evolution". International Journal of Advanced Geosciences 9, n. 2 (16 ottobre 2021): 65. http://dx.doi.org/10.14419/ijag.v9i2.31253.

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Abstract (sommario):

Rocks of the northern part of Birnin Gwari schist belt is underlain predominantly by (i) banded gneiss of dioritic and granodioritic composition and granitic gneisses; (ii) biotite-staurolite quartz schist; and (iii) syn-tectonic biotite hornblende (quartzolite - BHG) granite, biotite granite (BG), and biotite-muscovite granite (BMG). Banded gneiss rocks are of hybrid sedimentary–igneous protoliths; their pelitic and mafic protoliths were derived essentially from a quartz-diorite, granodiorite and granite-quartz monzonite source. Metasediments are enriched in SiO2 (63.03 to 65.13 wt %), with moderately elevated Al2O3 (15.4 – 15.16 wt %) values and depleted in Ba, V, W, La, Nb, Nd, Rb, Th and Zr trace elements; inherited from shale-greywacke sedimentary protoliths. Cogenetic syn-tectonic granites display similar trace elements and REE patterns, with diverse trends such as “normal”, “anomalous” and “strongly differentiated” and characterized by LILE enrichment, high LREE fractionation factor (La/Yb of 6.74 to 45.14) with weak to moderate negative Eu (Eu/Eu* = 0.38 to 0.62) and strong negative Nb, P and Ti anomalies. The belt consists of rocks with alkaline affinity and evolved as back arc behind subducted Pan-African plate due effect of compressional forces and differentiation of quartz diorite, granodioritic and granite-quartz monzonite magma and partial melting of crustal components inherited from shale-greywacke sedimentary protoliths in volcanic arc and post collisional settings. The precursor of these rocks originated from basalt of depleted mantle that differentiated progressively to the granite.

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Guryanov, S. A. "Structural and tectonic conditions for the development of the Bering Sea sedimentary basin". Proceedings of higher educational establishments. Geology and Exploration, n. 4 (14 novembre 2022): 54–63. http://dx.doi.org/10.32454/0016-7762-2022-64-4-54-63.

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Introduction. In order to characterize the oil and gas potential of any area under exploration, its structural and tectonic evolution should be studied. In this paper, a structural and tectonic modelling of the Bering Sea is carried out.Aim. To identify the structural and tectonic characteristics of the Bering Sea by interpreting the results obtained during a geodynamic analysis of sedimentary basin formation, based on the tectonic and geodynamic paleoreconstructions and sedimentary basin modelling of the Bering Sea.Materials and methods. A structural and tectonic modelling of the Bering Sea sedimentary basins was carried out using contemporary methods of basin analysis and numerical geological modelling (PetroMod software, Schlumberger). Three-dimensional time-spatial structural-tectonic models of the Bering Sea were formed using the bottom structural maps of Pliocene-Quaternary deposits, near the Lower Miocene and Oligocene tops and along the acoustic basement bottom. Maps were digitalized and converted to grids (with a 500-m step), in which the discrepancies (intersections) were removed taking into account the available geological and geophysical data (seismogeological sections). The contemporary surface of sedimentary basins was constructed by the connection of bathymetric and topographic maps. The beginning and end time of sedimentary accumulation periods was determined in accordance with the international stratigraphic scale.Results. The performed study identified the sufficiently continuous development areas of the oceanic or suboceanic crust of deep-water (back-arc) basins, aged from the Upper Jurassic-Cretaceous to the Cenozoic and repeatedly affected by the subsequent phases of the tectonic and magmatic activation; development belts of the Cretaceous-Cenozoic block-magmatic basement of island arcs, locally including reformed basement blocks of an older, Paleozoic or Cimmerian, consolidation; extensive depth-differentiated alpine/newest (syn-oceanic) shelf platforms, occassionally partially destroyed due to the latest destruction, including blocks or large blocks of Pre-Cambrian or Paleozoic relatively rigid massifs in the structure of their base.Conclusion. The modelling results indicate the deeply submerged West Anadyr, East Anadyr and Central Anadyr basins to be possible depocentres with their own hydrocarbon generation centres.

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Poisson, André, Fabienne Orszag-Sperber, Erdal Kosun, Maria-Angella Bassetti, Carla Müller, Roland Wernli e Jean-Marie Rouchy. "The Late Cenozoic evolution of the Aksu basin (Isparta Angle; SW Turkey). New insights". Bulletin de la Société Géologique de France 182, n. 2 (1 marzo 2011): 133–48. http://dx.doi.org/10.2113/gssgfbull.182.2.133.

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Abstract The Mio-Pliocene basins around the Antalya gulf in SW Turkey developed above the Tauric Mesozoic platforms on which the Antalya nappes had been thrusted (in Late Cretaceous-Paleocene times). The closure of the initial Isparta Angle during these events (E-W compression) initiated the N-S orientation of the main structural lines, which persisted later and explains the orientation of the Aksu basin in contrast with the E-W orientation of the eastern Neo-gene Mediterranean basins. The area, and all southwestern Turkey, became emergent at the end of the Oligocene and were the site of shallow-marine carbonate deposits in the Chattian-Aquitanian, giving way to the wide Lycian basin in Burdigalian-Langhian times. The progressive emplacement of the Lycian nappes from the north over this basin provoked first its subsidence and then its emersion when the nappes attained their final position over the Bey Daglari platform in Langhian times. Coinciding, or in response to the Lycian nappes emplacement, the Aksu basin was initiated as an elongated N-S graben which was filled by thick accumulations of terrestrial and marine deposits(including coral reefs), which derived from the erosion of the Lycian allochton and its basement (Langhian?, Serravallian and Tortonian times). The syn-sedimentary tectonics : reactivation of the normal faults along the west margin of the basin, the continuous uplift of the neighbouring continental areas (beginning of the Aksu thrust), governed the geometry of the basin. As a result and due to the uplift of its northern margin, the Aksu basin migrated towards the south and in Messinian times it was reduced to a narrow gulf along the eastern margin of which the Gebiz limestones were deposited as fringing coral reefs. The age of these limestones has been debated. Our new data allow us to attribute them to the Messinian. The drastic retreat of the sea at the end of this period, provoked the erosion of large parts of the Messinian deposits and the formation of deep canyons on land and under the sea down to the Antalya abyssal plain, in which evaporites were deposited. During the Zanclean transgression, the Eskiköy-Kargi canyon was filled by coarse clastics of a Gilbert delta derived from the northern continental area following a model well known elsewhere in the Mediterranean basins. Southward, shallow-marine sands and marls unconformably cover the remnants of the Messinian deposits and the emergent areas of the southern Antalya gulf. After Zanclean times (end of Pliocene?), the Aksu basin was deformed, due to the west-directed Aksu compressional event (end of the Aksu thrust). Quaternary terraces of the Aksu river at various altitudes, as well as the terraces of the Antalya tufa can be related to sea level fluctuations.

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Whitham, A. G., e J. E. A. Marshall. "Syn-depositional deformation in a Cretaceous succession, James Ross Island, Antarctica. Evidence from vitrinite reflectivity". Geological Magazine 125, n. 6 (novembre 1988): 583–91. http://dx.doi.org/10.1017/s0016756800023402.

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AbstractA detailed vitrinite reflectivity study has been made through the Cretaceous sedimentary rocks of northwest James Ross Island, Antarctica. The results show that a progressive increase in reflectivity does not occur with depth and that values (0.45 %) from the base of the succession are lower than expected for the sequence as described by previous authors. Using a synthesis of sedimentological and stratigraphic information, the sequence is reinterpreted as an apparent monoclinal syncline, strongly influenced by syndepositional tectonics, with a thickness appreciably less than previously described.

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Kusnida, Dida, e Tommy Naibaho. "LATE NEOGENE SEISMIC STRUCTURES OF THE SOUTH BATANTA BASIN, WEST PAPUA". BULLETIN OF THE MARINE GEOLOGY 29, n. 1 (15 febbraio 2016): 11. http://dx.doi.org/10.32693/bomg.29.1.2014.61.

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Study on multi-channel seismic records from South Batanta Basin, West Papua acquired during RV Geomarin III cruise in 2013 were aimed to invent and map geological aspects and for geo-tectonic and geological history studies. Seismic data indicate that sediment sequences which can be observed from our seismic system in the study area are characterized by pre-extension sediments (Lower Early Miocene-Upper Early Pliocene), syn-extension sediments (Lower Middle Pliocene-Upper Late Pliocene), post-extension sediments (Early Pleistocene), and syn-inversion sediments (Late Pleistocene-Recent) typical of the West Papua tectonic system. In the study area, sediment sequences are possibly characterized by clastical sedimentary cover such as slumps, debrites and turbidites. Key words: South Batanta Basin, seismic sequence, tectonic, faults, clastical sediments. Studi rekaman seismik multi kanal dari Cekungan Batanta Selatan, Papua Barat yang diperoleh selama pelayaran KR Geomarin III pada tahun 2013 bertujuan untuk menginventarisir dan memetakan aspek-aspek geologi serta untuk studi geo-tektonik dan sejarah geologi. Data seismik menunjukkan bahwa urutan sedimen yang dapat diamati dari sistem seismik di daerah studi ditandai oleh sedimen pra-ekstensi (Miosen Awal Bagian Bawah-Pliosen Awal Bagian Atas), sedimen syn-ekstensi (Pliosen Tengah Bagian Bawah-Pliosen Akhir Bagian Atas), sedimen post-ekstensi (Plestosen Awal), dan sedimen syn-inversi (Pleistosen Akhir-Resen) tipikal sistem tektonik Papua Barat. Di daerah studi, urutan sedimen dicirikan oleh sedimen penutup klastika kemungkinan berupa slump, debrit dan turbidit. Kata kunci: Cekungan Batanta Selatan, sekuen seismik, tektonik, sesar, sedimen klastika.

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Liu, Jin Shui, Ming Zhang, Jin Liang Zhang, Chun Yan Wang e Peng Hui Zhang. "Tectonic Evolution and Sequence Filling of Paleocene in Lishui Sag, East China Sea Shelf Basin". Advanced Materials Research 807-809 (settembre 2013): 2244–48. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.2244.

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The Lishui sag located at Southwest of the East China Sea Shelf Basin. It had undergone the four stages of syn-rift processes in Late Cretaceous to Paleocene: initial rift stage, main rift stage, stable rift stage and decline stage. The tectonic evolution has control effect on the development of sequence stratigraphy and the sediments distribution. Three second-order sequences, five third-order sequences and twelve system tracts are distinguished. Different sedimentary facies recognized in the Lishui sag.

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Vozárová, Anna, Katarína Šarinová, Dušan Laurinc, Elena Lepekhina, Jozef Vozár, Nickolay Rodionov e Pavel Lvov. "Exhumation history of the Variscan suture: Constrains on the detrital zircon geochronology from Carboniferous–Permian sandstones (Northern Gemericum; Western Carpathians)". Geologica Carpathica 70, n. 6 (1 dicembre 2019): 512–30. http://dx.doi.org/10.2478/geoca-2019-0030.

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Abstract The Late Paleozoic sedimentary basins in the Northern Gemericum evolved gradually in time and space within the collisional tectonic regime of the Western Carpathian Variscan orogenic belt. The detrital zircon age spectra, obtained from the Mississippian, Pennsylvanian and Permian metasediments, have distinctive age distribution patterns that reflect the tectonic setting of the host sediments. An expressive unimodal zircon distribution, with an age peak at 352 Ma, is shown by the basal Mississippian metasediments. These represent a relic of the convergent trench-slope sedimentary basin fill. In comparison, the Pennsylvanian detrital zircon populations display distinct multimodal distributions, with the main age peaks at 351, 450, 565 Ma and smaller peaks at ~2.0 and ~2.7 Ga. This is consistent with derivation of clastic detritus from the collisional suture into the foreland basin. Similarly, the Permian sedimentary formations exhibit the multimodal distribution of zircon ages, with main peaks at 300, 355 and 475 Ma. The main difference, in comparison with the Pennsylvanian detrital zircon assemblages, is the sporadic occurrence of the Kasimovian– Asselian (306–294 Ma), as well as the Artinskian–Kungurian (280–276 Ma) igneous zircons. The youngest magmatic zircon ages nearly correspond to the syn-sedimentary volcanic activity with the depositional age of the Permian host sediments and clearly indicate the extensional, rift-related setting.

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Zakir, Abdelali, Ahmed Chalouan e Hugues Feinberg. "Tectono-sedimentary evolution of a fore-chain domain : example of the Habt and Sidi Mrayt basins, northwestern external Moroccan Rif ; stratigraphic precisions and tectonic modelling". Bulletin de la Société Géologique de France 175, n. 4 (1 luglio 2004): 383–97. http://dx.doi.org/10.2113/175.4.383.

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Abstract In this paper, a tecto-sedimentary evolution model of the northwestern external Rif zones (Morocco) is proposed. It is based on the study of structural relationships and the biostratigraphic and sedimentologic analysis of different Tertiary syn-tectonic units. This zone shows alternating foredeep basins and anticlinal ramps with a NNW-SSE structural trend and a vergence toward the WSW. The trend of turbiditic bodies and palaeocurrent directions (from the SSE to the NNW) are parallel to the regional tectonic strike. Sidi Mrayt and El Habt basins are filled with syn-tectonic middle Eocene to middle Miocene sediments; The Habt basin is subdivided in two sub-basins: Asilah-Larache and Rirha-Gzoula. The deposits are distributed in two separated turbiditic complex, each one including a stacking of turbiditic systems. The Rirha-Gzoula and Asilah-Larache sub-basins are located in front of two anticline ridge structures made up of Upper Cretaceous and Lower Eocene material; they are respectively Boujediane and Arbaa Ayacha anticlines. The distribution of turbiditic bodies, unconformities and structural relationships within the thrusts and folds system in the northwestern external Rif indicate the progression toward the external zones of fault-propagation folds and associated basins.

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Lloret, Joan, Raúl De la Horra, José López-Gómez, José F. Barrenechea, Nicola Gretter e Ausonio Ronchi. "Permian and Triassic paleosols in the fluvial-lacustrine record of the central Pyrenees Basin, Spain: A stratigraphic tool for interpreting syn-tectonic sedimentary evolution and paleoclimate". Newsletters on Stratigraphy 54, n. 3 (28 giugno 2021): 377–404. http://dx.doi.org/10.1127/nos/2021/0625.

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Kafle, Nirmal, Lelin Raj Dhungel, Kamala Kanta Acharya e Megh Raj Dhital. "A Balanced Geological Cross-Section along Kohalpur – Surkhet Area of Sub-Himalayan Range, Mid-Western Nepal". Journal of Science and Engineering 6 (3 maggio 2019): 1–8. http://dx.doi.org/10.3126/jsce.v6i0.23960.

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The Sub-Himalayans Zone comprises a tectonic wedge of syn-orogenic sediments along the outer Himalayan Belt. Sediments are integrated into the accretionary prism from the foreland Indo-Gangetic plain, undergo a tectonic cycle within it, and eventually are eroded. The structural sketch map unveils westward-plunging arcuate structures on the leading location of the Outer Belt. A balanced cross-section has been constructed across the Sub-Himalayan Hills of the Kohalpur-Surkhet region of mid-western Nepal in order to determine the structural geometry of the region and to calculate tectonic shortening. The mid-western Nepal Sub-Himalaya has an emergent splay fan geometry with no major prevailing thrust contains the Main Boundary Thrust (MBT), the Bheri Thrust, the Babai Thrust and the Main frontal Thrust (MFT) which are all imbricate of the main decollment which ramp up-section through the 5 km thick tectonic sedimentary prism. North-south shortening across the mid-western Nepal, Kohalpur-Surkhet section has been approximately 29 km, or 55% shortening.

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43

Lotero‐Vélez, A., I. Yarbuh, O. Borges‐Santana, R. M. Spelz‐Madero, R. Negrete‐Aranda e J. Contreras. "Autogenic Organization of Syn‐Tectonic Sedimentary Patterns in Deepwater Foldbelts: A Simple Dynamic Model". Journal of Geophysical Research: Earth Surface 124, n. 12 (dicembre 2019): 2823–40. http://dx.doi.org/10.1029/2019jf005153.

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44

Smeraglia, Luca, Nathan Looser, Olivier Fabbri, Flavien Choulet, Marcel Guillong e Stefano M. Bernasconi. "U–Pb dating of middle Eocene–Pliocene multiple tectonic pulses in the Alpine foreland". Solid Earth 12, n. 11 (9 novembre 2021): 2539–51. http://dx.doi.org/10.5194/se-12-2539-2021.

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Abstract. Foreland fold-and-thrust belts (FTBs) record long-lived tectono-sedimentary activity, from passive margin sedimentation, flexuring, and further evolution into wedge accretion ahead of an advancing orogen. Therefore, dating fault activity is fundamental for plate movement reconstruction, resource exploration, and earthquake hazard assessment. Here, we report U–Pb ages of syn-tectonic calcite mineralizations from four thrusts and three tear faults sampled at the regional scale across the Jura fold-and-thrust belt in the northwestern Alpine foreland (eastern France). Three regional tectonic phases are recognized in the middle Eocene–Pliocene interval: (1) pre-orogenic faulting at 48.4±1.5 and 44.7±2.6 Ma associated with the far-field effect of the Alpine or Pyrenean compression, (2) syn-orogenic thrusting at 11.4±1.1, 10.6±0.5, 9.7±1.4, 9.6±0.3, and 7.5±1.1 Ma associated with the formation of the Jura fold-and-thrust belt with possible in-sequence thrust propagation, and (3) syn-orogenic tear faulting at 10.5±0.4, 9.1±6.5, 5.7±4.7, and at 4.8±1.7 Ma including the reactivation of a pre-orogenic fault at 3.9±2.9 Ma. Previously unknown faulting events at 48.4±1.5 and 44.7±2.6 Ma predate the reported late Eocene age for tectonic activity onset in the Alpine foreland by ∼10 Myr. In addition, we date the previously inferred reactivation of pre-orogenic strike-slip faults as tear faults during Jura imbrication. The U–Pb ages document a minimal time frame for the evolution of the Jura FTB wedge by possible in-sequence thrust imbrication above the low-friction basal decollement consisting of evaporites.

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Thinon, Isabelle, Jean-Pierre Réhault e Luis Fidalgo-González. "The syn-rift sedimentary cover of the North Biscay Margin (bay of Biscay): from new reflection seismic data". Bulletin de la Société Géologique de France 173, n. 6 (1 novembre 2002): 515–22. http://dx.doi.org/10.2113/173.6.515.

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Abstract The Armorican Basin is a deep sedimentary basin lying at the footside of the North Bay of Biscay. From previous scattered inadequate data, the age and nature of this basin, oceanic domain or deep part of the Armorican margin itself were largely speculated. From this new seismo-stratigraphic study based on a dense seismic cover, the sedimentation within the Armorican Basin is beginning in the Aptian times, during the last tectonic rifting episode of the margin. The first sediments formation identified as the « 3B layer » is characterised on the profiles by a chaotic and transparent seismic facies and was emplaced by slumping process when the margin collapsed, at the final rifting phase, just before the oceanic accretion. The new seismic reflection data give also some informations on the polyphased evolution of the North Biscay Margin during the rifting period. Two main events occurred during the Lower Cretaceous times (the first one is pre-Berriasian, the second is Aptian), separated by a quiet tectonic period including the Upper Berriasian and Lower Aptian times. The first event is responsible of the margin tectonic structuration in some blocks, the second of collapsing and the emplacement of the allochthonous sediments (3B layer) in the Armorican Basin.

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UNDERWOOD, C. J., e S. F. MITCHELL. "Mid-Cretaceous onlap history of the Market Weighton structural high, northeast England". Geological Magazine 136, n. 6 (novembre 1999): 681–96. http://dx.doi.org/10.1017/s0016756899003167.

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The mid-Cretaceous sediments of northeast England were deposited at the western margin of the southern North Sea Basin, with sedimentation occurring in a range of tectonic settings. Detailed analysis of the areal distribution and sedimentary facies of Aptian to earliest Cenomanian sediments has allowed the pattern of onlap onto the Market Weighton structural high and changes in relative sea level to be documented. Successive onlap episodes during the Early Aptian, Late Aptian and Early Albian culminated in the final flooding of the structure during the Late Albian (varicosum Subzone). Sea-level curves generated from coastal onlap patterns are difficult to relate to published ‘global’ sea-level curves due to the high frequency of the fluctuations in relative sea level observed. Despite this, detailed correlation and analysis of sedimentological events suggest that even the most expanded, basinal succession is relatively incomplete. This study has also shown that the change from dominantly syn-tectonic to dominantly post-tectonic sedimentation style occurred in the late Early Albian.

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Liu, Deng, Dai Yong Cao, Yi Wu Wang e Zhong Yuan Liu. "Geochemical Characteristics and Tectonic Implications of the early Permian Volcanic Rocks from Ongniud Banner, Inner Mongolia". Advanced Materials Research 734-737 (agosto 2013): 344–51. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.344.

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The Early Permian volcanic-sedimentary sequences of Ongniud Banner consist mainly of andesite, rhyolite, perlite, volcanic breccia, tuff, tuffaceous sandstone, siliceous rock. Rock assemblage and sedimentary formations indicate that are of fore-arc basin sedimentary feature between subduction zone and island arc in Early Permian. The volcanic rocks from Elitu Formation have SiO2=50.23%~74.83%, Mg#=6.21~49.54, Na2O+K2O=5.27%~10.73%, Na2O/K2O=0.36~4.17, belonging to high-K cal-alkaline (HKCA)~shoshonite (SHO) series. The volcanic rocks are characterized with (La/Yb)N=5.52~9.89, moderate - intense negative Eu anomalies, LILE enrichment such as Ba, Ra, K, Th and HFSE depletion such as Ta, Nb, P, Ti, and indicating that magma could be formed in the tectonic setting of the island arc and active continental margin related to the plate subduction. R1-R2 diagram also indicates that volcanic rocks were generated at syn-collision or post-orogenic period, perhaps representing the mid-later subduction stage of the Palaeo-Asian Ocean Plate and North China Plate. Taken together, the authors suggest that the region was located still in the Palaeo-Asian Ocean, rather than the intracontinental taphrogenic trough in Early Permian.

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Stokke, Ella W., Deta Gasser, Bjørgunn H. Dalslåen e Tor Grenne. "Tectonic evolution of syn- to late-orogenic sedimentary–volcanic basins in the central Norwegian Caledonides". Journal of the Geological Society 175, n. 4 (22 febbraio 2018): 605–18. http://dx.doi.org/10.1144/jgs2017-091.

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49

He, Bizhu, Xiufu Qiao, Cunli Jiao, Zhiqin Xu, Zhihui Cai, Xianpu Guo e Yinli Zhang. "Palaeo-earthquake events during the late Early Palaeozoic in the central Tarim Basin (NW China): evidence from deep drilling cores". Geologos 20, n. 2 (8 luglio 2014): 105–23. http://dx.doi.org/10.2478/logos-2014-0006.

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Abstract Various millimetre-, centimetre- and metre-scale soft-sediment deformation structures (SSDS) have been identified in the Upper Ordovician and Lower-Middle Silurian from deep drilling cores in the Tarim Basin (NW China). These structures include liquefied-sand veins, liquefaction-induced breccias, boudinage-like structures, load and diapir- or flame-like structures, dish and mixed-layer structures, hydroplastic convolutions and seismic unconformities. The deformed layers are intercalated by undeformed layers of varying thicknesses that are petrologically and sedimentologically similar to the deformed layers. The SSDS developed in a shelf environment during the early Late Ordovician and formed initially under shear tensile stress conditions, as indicated by boudinage-like structures; during the latest Ordovician, SSDS formed under a com-pressional regime. The SSDS in the Lower-Middle Silurian consist mainly of mixed layers and sand veins; they formed in shoreline and tidal-flat settings with liquefaction features indicating an origin under a compressional stress regime. By Silurian times, the centre of tectonic activity had shifted to the south-eastern part of the basin. The SSDS occur at different depths in wells that are close to the syn-sedimentary Tazhong 1 Fault (TZ1F) and associated reversed-thrust secondary faults. Based on their characteristics, the inferred formation mechanism and the spatial association with faults, the SSDS are interpreted as seismites. The Tazhong 1 fault was a seismogenic fault during the later Ordovician, whereas the reversed-direction secondary faults became active in the Early-Middle Silurian. Multiple palaeo-earthquake records reflect pulses and cyclicity, which supports secondary tectonic activity within the main tectonic movement. The range of SSDS structures reflects different developments of tectonic activity with time for the various tectonic units of the centralbasin. The effects of the strong palaeo-earthquake activity coincide with uplift, fault activity and syn-tectonic sedimentation in the study area during the Late Ordovician to Middle Silurian.

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CATALANO, STEFANO, ROSOLINO CIRRINCIONE, PAOLO MAZZOLENI, FRANCESCO PAVANO, ANTONIO PEZZINO, GINO ROMAGNOLI e GIUSEPPE TORTORICI. "The effects of a Meso-Alpine collision event on the tectono-metamorphic evolution of the Peloritani mountain belt (eastern Sicily, southern Italy)". Geological Magazine 155, n. 2 (15 giugno 2017): 422–37. http://dx.doi.org/10.1017/s0016756817000413.

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AbstractThe Peloritani Mountains, in the southern part of the Calabrian Terranes, southern Italy, have been classically interpreted as the product of the Paleogene brittle deformation of the European continental back-stop of the Neotethyan subduction complex. This reconstruction conflicts with the occurrence of an Alpine metamorphic overprint that affected portions of both the Variscan metamorphic units and part of the Mesozoic sedimentary covers of the mountain belt. New field data, integrated with petrographic, micro- and meso-structural analyses and stratigraphic investigation of the syn-tectonic terrigenous covers, well constrain a Paleogene collision event along the Africa–Nubia convergent margin that caused the exhumation of the Alpine metamorphic units of the Peloritani Mountains. The syn-collisional exhumation was associated with shearing along two major Africa-verging crustal thrusts arising from the positive tectonic inversion of the former European palaeomargin. Early tectonic motions occurred within the mountain belts and produced the exhumation of the external portions of the edifice. Later tectonic motions occurred along the sole-thrust of the entire edifice and caused the definitive exhumation of the entire mountain belt. The whole crustal thrusting lasted for a period ofc. 10 Ma, during the entire Oligocene. The definitive southwestward emplacement of the Peloritani Mountain Belt onto the Neotethyan accretionary wedge was followed by two Late Oligocene – Early Miocene NW–SE-oriented right lateral shear zones, replacing the previous crustal thrust. These two strike-slip belts are interpreted as the surface expression of the deep-seated suture zone between the colliding Africa and Europe continental crusts.

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