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Siamak, Mansouri Far. "Geothermal field of the transition area between the Anatolian Plate and the East European Platform." Journal of the Belarusian State University. Geography and Geology, no. 2 (November 29, 2019): 133–48. http://dx.doi.org/10.33581/2521-6740-2019-2-133-148.
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Heat flow data from the Eastern Mediterranean region indicates an extensive province of low heat flow, spreading over the whole basin of the Mediterranean to the east of Crete (Levantine Sea), Cyprus, and Northern Egypt. Surface geology of East Anatolia is complex because of recent active tectonic and volcanic activity. The region is composed of major tectonic units of Pontides, the Anatolid-Tauride Belt and Bitlis Suture Zone, North and East Anatolian faults. Ophiolitic and young volcanic rocks can be observed in many parts of East Anatolia. The Black Sea is surrounded by the Alpine-Himalayan Orogenic Belt of Crimea, Greater Caucasus, Pontides, Rhodope-Stranja Massif, Eastern Srednegorie, North Dobrogea and older tectonic units of different origins and ages such as the Precambrian East European Craton, Moesian Platform, Istanbul Zone and Adzhar-Trialet Folded System. Low heat flow density dominates in the Black Sea. The lowest (less•30 mW/m2 ) values have been recorded in central parts of the Western and Eastern Black Sea basins with maximal sedimentary thickness. Geothermal studies within the territories of Ukraine have been under way since sixties. Many important features of the thermal field remain unstudied. This applies in particular to the Ukrainian Shield and to the southern part of the Carpathian region. In general, the territory of Alpine folding within Turkey, Marmara and Aegean seas, Caucasus is characterized by high heat flow. The anomaly of its highest values (above 100 –150 mW/m2 ) exists within western Turkey, where tectonic conditions of extension prevail and underground steam is used to produce electricity. Three heat flow density profiles crossing the studied region and heat flow map were compiled.
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De Capoa, Paola. "Biostratigraphic constraints for the paleogeographic and tectonic evolution of the Alpine Central-Western Mediterranean orogenic belt (Betic, Maghrebian and Apenninic chains)." Rendiconti Online della Società Geologica Italiana, Vol. 25 (April 16, 2013): 43–63. http://dx.doi.org/10.3301/rol.2013.04.
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Doblas, Miguel, and Roberto Oyarzun. "Neogene extensional collapse in the western Mediterranean (Betic-Rif Alpine orogenic belt): Implications for the genesis of the Gilbraltar Arc and magmatic activity." Geology 17, no. 5 (1989): 430. http://dx.doi.org/10.1130/0091-7613(1989)017<0430:necitw>2.3.co;2.
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de Lamotte, Dominique Frizon, Jean-Claude Guezou, Jean Andrieux, Marie-Anne Albertini, Michel Coulon, André Poisson, Miguel Doblas, and Roberto Oyarzun. "Comment and Reply on "Neogene extensional collapse in the western Mediterranean (Betic-Rif Alpine orogenic belt): Implications for the genesis of the Gibraltar Arc and magmatic activity"." Geology 18, no. 4 (1990): 381. http://dx.doi.org/10.1130/0091-7613(1990)018<0381:carone>2.3.co;2.
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Le Breton, Eline, Sascha Brune, Kamil Ustaszewski, Sabin Zahirovic, Maria Seton, and R. Dietmar Müller. "Kinematics and extent of the Piemont–Liguria Basin – implications for subduction processes in the Alps." Solid Earth 12, no. 4 (April 21, 2021): 885–913. http://dx.doi.org/10.5194/se-12-885-2021.
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Abstract. Assessing the size of a former ocean of which only remnants are found in mountain belts is challenging but crucial to understanding subduction and exhumation processes. Here we present new constraints on the opening and width of the Piemont–Liguria (PL) Ocean, known as the Alpine Tethys together with the Valais Basin. We use a regional tectonic reconstruction of the Western Mediterranean–Alpine area, implemented into a global plate motion model with lithospheric deformation, and 2D thermo-mechanical modeling of the rifting phase to test our kinematic reconstructions for geodynamic consistency. Our model fits well with independent datasets (i.e., ages of syn-rift sediments, rift-related fault activity, and mafic rocks) and shows that, between Europe and northern Adria, the PL Basin opened in four stages: (1) rifting of the proximal continental margin in the Early Jurassic (200–180 Ma), (2) hyper-extension of the distal margin in the Early to Middle Jurassic (180–165 Ma), (3) ocean–continent transition (OCT) formation with mantle exhumation and MORB-type magmatism in the Middle–Late Jurassic (165–154 Ma), and (4) breakup and mature oceanic spreading mostly in the Late Jurassic (154–145 Ma). Spreading was slow to ultra-slow (max. 22 mm yr−1, full rate) and decreased to ∼5 mm yr−1 after 145 Ma while completely ceasing at about 130 Ma due to the motion of Iberia relative to Europe during the opening of the North Atlantic. The final width of the PL mature (“true”) oceanic crust reached a maximum of 250 km along a NW–SE transect between Europe and northwestern Adria. Plate convergence along that same transect has reached 680 km since 84 Ma (420 km between 84–35 Ma, 260 km between 35–0 Ma), which greatly exceeds the width of the ocean. We suggest that at least 63 % of the subducted and accreted material was highly thinned continental lithosphere and most of the Alpine Tethys units exhumed today derived from OCT zones. Our work highlights the significant proportion of distal rifted continental margins involved in subduction and exhumation processes and provides quantitative estimates for future geodynamic modeling and a better understanding of the Alpine Orogeny.
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Michard, André, Ahmed Chalouan, Hugues Feinberg, Bruno Goffé, and Raymond Montigny. "How does the Alpine belt end between Spain and Morocco ?" Bulletin de la Société Géologique de France 173, no. 1 (January 1, 2002): 3–15. http://dx.doi.org/10.2113/173.1.3.
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Abstract The Betic-Rif arcuate mountain belt (southern Spain, northern Morocco) has been interpreted as a symmetrical collisional orogen, partly collapsed through convective removal of its lithospheric mantle root, or else as resulting of the African plate subduction beneath Iberia, with further extension due either to slab break-off or to slab retreat. In both cases, the Betic-Rif orogen would show little continuity with the western Alps. However, it can be recognized in this belt a composite orocline which includes a deformed, exotic terrane, i.e. the Alboran Terrane, thrust through oceanic/transitional crust-floored units onto two distinct plates, i.e. the Iberian and African plates. During the Jurassic-Early Cretaceous, the yet undeformed Alboran Terrane was part of a larger, Alkapeca microcontinent bounded by two arms of the Tethyan-African oceanic domain, alike the Sesia-Margna Austroalpine block further to the northeast. Blueschist- and eclogite-facies metamorphism affected the Alkapeka northern margin and adjacent oceanic crust during the Late Cretaceous-Eocene interval. This testifies the occurrence of a SE-dipping subduction zone which is regarded as the SW projection of the western Alps subduction zone. During the late Eocene-Oligocene, the Alkapeca-Iberia collision triggered back-thrust tectonics, then NW-dipping subduction of the African margin beneath the Alboran Terrane. This Maghrebian-Apenninic subduction resulted in the Mediterranean basin opening, and drifting of the deformed Alkapeca fragments through slab roll back process and back-arc extension, as reported in several publications. In the Gibraltar area, the western tip of the Apenninic-Maghrebian subduction merges with that of the Alpine-Betic subduction zone, and their Neogene roll back resulted in the Alboran Terrane collage astride the Azores-Gibraltar transpressive plate boundary. Therefore, the Betic-Rif belt appears as an asymmetrical, subduction/collision orogen formed through a protracted evolution straightfully related to the Alpine-Apenninic mountain building.
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Lardeaux, Jean-Marc. "Deciphering orogeny: a metamorphic perspective Examples from European Alpine and Variscan belts." Bulletin de la Société Géologique de France 185, no. 5 (May 1, 2014): 281–310. http://dx.doi.org/10.2113/gssgfbull.185.5.281.
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AbstractIn this paper we review and discuss, in a synthetic historical way, the main results obtained on Variscan metamorphism in the French Massif Central. First, we describe the pre-orogenic architecture of the French Massif Central on the base of available lithostratigraphic and geochemical constraints. Second, we portray the progressive metamorphic evolution through time and space with the presentation of 6 metamorphic maps corresponding to critical orogenic periods, namely 430–400 Ma, 400–370 Ma, 370–360 Ma, 360–345 Ma, 340–325 Ma and 320–290 Ma. We discuss the role of multiple subductions in orogeny, the metamorphic effects of continental collision (i.e. regional development of intermediate-pressure metamorphic series) as well as the links between post-thickening tectonics and the regional development of low-pressure metamorphic series coeval with crustal partial melting. As it was the case for the western Alps, we emphasize the lack of temporal data on high-pressure/low-temperature metamorphic rocks as well as the uncertainties on the sizes of rock units that have recorded the same metamorphic history (i.e. coherent P-T-t/deformation trajectories). Finally, we underline the main differences and similarities between the metamorphic evolutions of the western Alps and the French Massif Central.
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Lardeaux, Jean-Marc. "Deciphering orogeny: a metamorphic perspective. Examples from European Alpine and Variscan belts." Bulletin de la Société Géologique de France 185, no. 2 (February 1, 2014): 93–114. http://dx.doi.org/10.2113/gssgfbull.185.2.93.
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AbstractIn this paper we review and discuss, in a synthetic historical way, the main results obtained on Alpine metamorphism in the western Alps. First, we describe the finite metamorphic architecture of the western Alps and discuss its relationships with subduction and collision processes. Second, we portray the progressive metamorphic evolution through time and space with the presentation of 5 metamorphic maps corresponding to critical orogenic periods, namely 85-65 Ma, 60-50 Ma, 48-40 Ma, 38-33 Ma and 30-20 Ma. We underline the lack of temporal data on high-pressure/low-temperature metamorphic rocks as well as the severe uncertainties on the sizes of rock units that have recorded the same metamorphic history (i.e. coherent P-T-t/deformation trajectories). We discuss the role of subduction-driven metamorphism in ocean-derived protoliths and the conflicting models that account for the diachrony of continental subductions in the western Alps.
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Erdős, Zoltán, Ritske S. Huismans, and Peter van der Beek. "Control of increased sedimentation on orogenic fold-and-thrust belt structure – insights into the evolution of the Western Alps." Solid Earth 10, no. 2 (March 13, 2019): 391–404. http://dx.doi.org/10.5194/se-10-391-2019.
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Abstract. We use two-dimensional thermomechanical models to investigate the potential role of rapid filling of foreland basins in the development of orogenic foreland fold-and-thrust belts. We focus on the extensively studied example of the Western European Alps, where a sudden increase in foreland sedimentation rate during the mid-Oligocene is well documented. Our model results indicate that such an increase in sedimentation rate will temporarily disrupt the formation of an otherwise regular, outward-propagating basement thrust-sheet sequence. The frontal basement thrust active at the time of a sudden increase in sedimentation rate remains active for a longer time and accommodates more shortening than the previous thrusts. As the propagation of deformation into the foreland fold-and-thrust belt is strongly connected to basement deformation, this transient phase appears as a period of slow migration of the distal edge of foreland deformation. The predicted pattern of foreland-basin and basement thrust-front propagation is strikingly similar to that observed in the North Alpine Foreland Basin and provides an explanation for the coeval mid-Oligocene filling of the Swiss Molasse Basin, due to increased sediment input from the Alpine orogen, and a marked decrease in thrust-front propagation rate. We also compare our results to predictions from critical-taper theory, and we conclude that they are broadly consistent even though critical-taper theory cannot be used to predict the timing and location of the formation of new basement thrusts when sedimentation is included. The evolution scenario explored here is common in orogenic foreland basins; hence, our results have broad implications for orogenic belts other than the Western Alps.
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GRANADO, P., W. THÖNY, N. CARRERA, O. GRATZER, P. STRAUSS, and J. A. MUÑOZ. "Basement-involved reactivation in foreland fold-and-thrust belts: the Alpine–Carpathian Junction (Austria)." Geological Magazine 153, no. 5-6 (February 23, 2016): 1110–35. http://dx.doi.org/10.1017/s0016756816000066.
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AbstractThe late Eocene – early Miocene Alpine–Carpathian fold-and-thrust belt (FTB) lies in the transition between the Eastern Alps and the Western Carpathians, SE of the Bohemian crystalline massif. Our study shows the involvement of crystalline basement from the former European Jurassic continental margin in two distinct events. A first extensional event coeval with Eggerian–Karpatian (c. 28–16 Ma) thin-skinned thrusting reactivated the rift basement fault array and resulted from the large degree of lower plate bending promoted by high lateral gradients of lithospheric strength and slab pull forces. Slab break-off during the final stages of collision around Karpatian times (c. 17–16 Ma) promoted large-wavelength uplift and an excessive topographic load. This load was reduced by broadening the orogenic wedge through the reactivation of the lower-plate deep detachment beneath and ahead of the thin-skinned thrust front (with the accompanying positive inversion of the basement fault array) and ultimately, by the collapse of the hinterland summits, enhanced by transtensional faulting. Although this work specifically deals with the involvement of the basement in the Alpine–Carpathian Junction, the main conclusions are of general interest to the understanding of orogenic systems.
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Cifelli, Francesca, Chiara Caricchi, and Massimo Mattei. "Formation of arc-shaped orogenic belts in the Western and Central Mediterranean: a palaeomagnetic review." Geological Society, London, Special Publications 425, no. 1 (2016): 37–63. http://dx.doi.org/10.1144/sp425.12.
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Molli, Giancarlo, and Jacques Malavieille. "Orogenic processes and structural heritage in Alpine-type mountain belts and Mediterranean region: A foreword and an introduction." Tectonophysics 579 (December 2012): 1–3. http://dx.doi.org/10.1016/j.tecto.2012.07.020.
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Casciello, Emilio, Manuel Fernàndez, Jaume Vergés, Massimo Cesarano, and Montserrat Torne. "The Alboran domain in the western Mediterranean evolution: the birth of a concept." Bulletin de la Société Géologique de France 186, no. 4-5 (July 1, 2015): 371–84. http://dx.doi.org/10.2113/gssgfbull.186.4-5.371.
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Abstract Since the early 70’s the majority of tectonic reconstructions of the western Mediterranean employ the Alboran domain notion as a migrating microcontinent or landmass mainly composed of Paleozoic-Triassic rocks affected by ‘Alpine’ HP-LT metamorphism. For nearly three decades, since the mid-80’s, the Alboran domain was considered as a fragment of the Alpine chain that moved westward, colliding into Iberia and North Africa to produce the Gibraltar arc and Betic-Rif chain. In 2012, a new hypothesis for the evolution of the western Mediterranean was presented in which the Betic-Rif orogenic chain originates from rollback of an initially SE-dipping subduction of the westernmost segments of the Ligurian-Tethys under the Africa margin. This interpretation considers the metamorphic ‘Alboran domain’ rocks as crustal successions of the hyper-extended African and Iberian continental margins, which have undergone a complete subduction-exhumation cycle above a NW- to W-retreating subduction. A key outcome of this hypothesis is that the Alboran domain is not a fragment of the Alpine chain but a consequence of rollback dynamics. In this contribution we try to elucidate the historical reasons behind the classical ‘Alpine’ interpretation of the Betic-Rif, by briefly describing key contributions, which appear linked in a logical sequence that traces the evolution of the Alboran domain concept since its original formulation by Andrieux and coauthors in 1971.
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BALESTRO, GIANNI, ANDREA FESTA, ALESSANDRO BORGHI, DANIELE CASTELLI, MARCO GATTIGLIO, and PAOLA TARTAROTTI. "Role of Late Jurassic intra-oceanic structural inheritance in the Alpine tectonic evolution of the Monviso meta-ophiolite Complex (Western Alps)." Geological Magazine 155, no. 2 (July 17, 2017): 233–49. http://dx.doi.org/10.1017/s0016756817000553.
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AbstractThe eclogite-facies Monviso meta-ophiolite Complex in the Western Alps represents a well-preserved fragment of oceanic lithosphere and related Upper Jurassic – Lower Cretaceous sedimentary covers. This meta-ophiolite sequence records the evolution of an oceanic core complex formed by mantle exhumation along an intra-oceanic detachment fault (the Baracun Shear Zone), related to the opening of the Ligurian–Piedmont oceanic basin (Alpine Tethys). On the basis of detailed geological mapping, and structural, stratigraphic and petrological observations, we propose a new interpretation for the tectonostratigraphic architecture of the Monviso meta-ophiolite Complex, and discuss the role played by structural inheritance in its formation. We document that subduction- and exhumation-related Alpine tectonics were strongly influenced by the inherited Jurassic intra-oceanic tectonosedimentary physiography. The latter, although strongly deformed during a major Alpine stage of non-cylindrical W-verging folding and faulting along exhumation-related Alpine shear zones (i.e. the Granero–Casteldelfino and Villanova–Armoine shear zones), was not completely dismembered into different tectonic units or subduction-related mélanges as suggested in previous interpretations. The present-day architecture of the Monviso meta-ophiolite Complex results from nappe-scale folding with a significant component of shearing, and strain partitioning of the Alpine deformation, which were controlled by the inherited occurrence of (i) lateral and vertical variations of facies and thickness of sediments, (ii) an intra-oceanic fault-rock assemblage, which acted as weak horizons in concentrating deformation, and (iii) remnants of a volcanic ridge, which consists of massive metabasalt. Thus, the recognition of pre-collisional, intra-oceanic, tectonostratigraphic inheritance represents an important step in reconstructing the tectonic evolution of meta-ophiolite units in orogenic belts.
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Lescoutre, Rodolphe, and Gianreto Manatschal. "Role of rift-inheritance and segmentation for orogenic evolution: example from the Pyrenean-Cantabrian system." BSGF - Earth Sciences Bulletin 191 (2020): 18. http://dx.doi.org/10.1051/bsgf/2020021.
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The Basque-Cantabrian junction corresponds to an inverted rift accommodation zone at the limit between the former hyperextended Pyrenean and Cantabrian rift segments. The recognition of an inherited rift segment boundary allows to investigate the reactivation associated with large-scale rift segmentation in an orogenic system. We use criteria from published field observations and seismic data to propose a new map of rift domains for the Basque-Cantabrian junction. We also provide balanced cross-sections that allow to define the along-strike architecture associated with segmentation during rifting and subsequent Alpine reactivation. Based on these results, this study aims to characterize and identify reactivated and newly formed structures during inversion of two rift segments and its intermitted segment boundary. It also aims to describe the timing of thin-skinned and thick-skinned deformation associated with the inversion of segmented rift systems. During convergence, two phases have been recognized within the rift segment (eastern Mauléon basin). The Late Cretaceous to Paleocene underthrusting/subduction phase was mostly governed by thin-skinned deformation that reactivated the former hyperextended domains and the supra-salt sedimentary cover. The Eocene to Miocene collisional phase, controlled by thick-skinned deformation that took place once necking domains collided and formed an orogenic wedge. At the rift segment boundary, the underthrusting/subduction phase was already controlled by thick-skinned deformation due to the formation of shortcutting thrust faults at the termination of overlapping V-shaped rift segments. This led to the formation of a proto-wedge composed of the Basque massifs. We suggest that this proto-wedge is responsible for the preservation of pre-Alpine structures in the Basque massifs and for the emplacement of subcontinental mantle rocks at a crustal level beneath the western Mauléon basin. These results argue for a first order cylindrical orogenic architecture from the Central Pyrenean segment to the Cantabrian segment (up to the Santander transfer zone) despite rift segmentation. They also highlight the control of 3D rift-inheritance for the initial phase of orogenic evolution and for the local architecture of mountain belts.
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Piana, Fabrizio, Luca Barale, Carlo Bertok, Anna d’Atri, Andrea Irace, and Pietro Mosca. "The Alps-Apennines Interference Zone: A Perspective from the Maritime and Western Ligurian Alps." Geosciences 11, no. 5 (April 25, 2021): 185. http://dx.doi.org/10.3390/geosciences11050185.
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In SW Piemonte the Western Alps arc ends off in a narrow, E-W trending zone, where some geological domains of the Alps converged. Based on a critical review of available data, integrated with new field data, it is concluded that the southern termination of Western Alps recorded the Oligocene-Miocene activity of a regional transfer zone (southwestern Alps Transfer, SWAT) already postulated in the literature, which should have allowed, since early Oligocene, the westward indentation of Adria, while the regional shortening of SW Alps and tectonic transport toward the SSW (Dauphinois foreland) was continuing. This transfer zone corresponds to a system of deformation units and km-scale shear zones (Gardetta-Viozene Zone, GVZ). The GVZ/SWAT developed externally to the Penninic Front (PF), here corresponding to the Internal Briançonnais Front (IBF), which separates the Internal Briançonnais domain, affected by major tectono-metamorphic transformations, from the External Briançonnais, subjected only to anchizonal metamorphic conditions. The postcollisional evolution of the SW Alps axial belt units was recorded by the Oligocene to Miocene inner syn-orogenic basin (Tertiary Piemonte Basin, TPB), which rests also on the Ligurian units stacked within the adjoining Apennines belt in southern Piemonte. The TPB successions were controlled by transpressive faults propagating (to E and NE) from the previously formed Alpine belt, as well as by the Apennine thrusts that were progressively stacking the Ligurian units, resting on the subducting Adriatic continental margin, with the TPB units themselves. This allows correlation between Alps and Apennines kinematics, in terms of age of the main geologic events, interference between the main structural systems and tectonic control exerted by both tectonic belts on the same syn-orogenic basin.
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Festa, Vincenzo, Marianna Cicala, and Fabrizio Tursi. "The Curinga–Girifalco Line in the framework of the tectonic evolution of the remnant Alpine chain in Calabria (southern Italy)." International Journal of Earth Sciences 109, no. 7 (September 12, 2020): 2583–98. http://dx.doi.org/10.1007/s00531-020-01918-5.
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Abstract In the peri-Mediterranean metamorphic belts, the tectonic evolution of the Calabria–Peloritani terrane during the dominant compressive tectonics of the Eocene represents one of the most problematic points in palinspastic restorations. A matter of particular debate is its shortening, which could have occurred during the Alpine or the Apennine subduction. In this regard, a crucial joint is provided by the kinematics of one of the most relevant shear zones such as the Curinga–Girifalco Line, cropping out in central Calabria. This shear zone juxtaposed a nearly complete Hercynian crustal section (i.e. the Sila and Serre Unit) onto the remnants of the Castagna Unit. The data in the available literature on ductile kinematics from the south-eastern branch of the Curinga–Girifalco Line indicate a downward movement of the hanging wall. In the present paper we show new, ductile kinematic data and petrographic evidence from outcrops in the north-western and south-eastern branches of the Curinga–Girifalco Line. Our results highlight the coherent kinematics of the Eocene shortening during the Alpine subduction system, followed by (late Eocene?)Oligocene to early Miocene, dominantly ductile extensional reworking, relating to the Apennines subduction system.
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Nowak, Arkadiusz, Sebastian Świerszcz, Sylwia Nowak, and Marcin Nobis. "Classification of tall-forb vegetation in the Pamir-Alai and western Tian Shan Mountains (Tajikistan and Kyrgyzstan, Middle Asia)." Vegetation Classification and Survey 1 (December 30, 2020): 191–217. http://dx.doi.org/10.3897/vcs/2020/60848.
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Aims: To complete the syntaxonomic scheme for tall-forb vegetation of the montane and alpine belts in the Pamir-Alai and western Tian Shan Mountains in Tajikistan and Kyrgyzstan with some remarks on its environmental predictors. Study area: Middle Asia: Tajikistan and Kyrgyzstan. Methods: A total of 244 relevés were sampled in 2013–2019 using the seven-degree cover-abundance scale of the Braun-Blanquet approach. These were classified with a modified TWINSPAN algorithm with pseudospecies cut-levels 0%, 5% and 25%, and total inertia as a measure of cluster heterogeneity. Diagnostic species were identified using the phi coefficient as a fidelity measure. NMDS was used to explore the relationships between the distinguished groups. Results: Our classification revealed 19 clusters of tall-forb vegetation in Middle Asia. Among others we found forb communities typical for Tian Shan, western Pamir-Alai, forb-scree vegetation of Pamir-Alai, dry tall-forbs and typical forbs of the alpine belt. A total of eight new tall-forb associations and five communities were distinguished. The forb vegetation of Middle Asia has been assigned to the class Prangetea ulopterae Klein. The main factors differentiating the species composition of the researched vegetation are elevation, mean annual temperature, sum of annual precipitation and inclination of the slope. Conclusions: The paper presents the first insight into the comprehensive classification of the alpine forb vegetation in Middle Asia and fosters progress in explaining the relationship of boreo-temperate and Mediterranean-like (Irano-Turanian) vegetation in western Asian and central Asian subregions of the Irano-Turanian phytogeographical region. Taxonomic references: The nomenclature of the vascular plants follows generally Cherepanov (1995) and for Bromus spp. The Plant List (2020) Version 1.1. http://www.theplantlist.org/. Syntaxonomic references: The names of syntaxa are used in accordance with Ermakov (2012), Gadghiev et al. (2002) and Nowak et al. (2018). Abbreviation: NMDS = Non-metric Multidimensional Scaling.
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Mascle, Georges H., Pierre Tricart, Luigi Torelli, Jean-Pierre Bouillin, Roberto Compagnoni, Stéphane Depardon, Jean Mascle, et al. "Structure of the Sardinia Channel: crustal thinning and tardi-orogenic extension in the Apenninic-Maghrebian orogen; results of the Cyana submersible survey (SARCYA and SARTUCYA) in the western Mediterranean." Bulletin de la Société Géologique de France 175, no. 6 (November 1, 2004): 607–27. http://dx.doi.org/10.2113/175.6.607.
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Abstract The Sardinia Channel is located in a 400 km-long submerged section of the Apennine-Maghrebian branch of the Alpine chain. The Sardinia Channel connects the Algerian-Ligurian-Provençal to the Tyrrhenian oceanic basins. The structure of this region results from the superposition of two tectonic regimes: an earlier crustal thickening and a later crustal thinning. The crustal thickening is the consequence of the shortening which occurred in the late Oligocene–early Miocene during the build up of the Apennine-Maghrebian Orogen. This thickening is coeval with the rotation of the Corsican-Sardinian block and the opening of the Provençal-Algerian back-arc basin. All of these structures, as well as the magmatic arcs in Sardinia and Tunisia, i.e. the Galite Archipelago, are connected to the subduction of the Tethyan Ocean. The crustal thinning is associated with the rifting of the Tyrrhenian Basin, which occurred just before the Messinian salinity crisis and was accompanied by significant erosion throughout the region. This erosion was followed by a period of thermal subsidence linked to the opening of the Tyrrhenian oceanic basin in the Plio-Quaternary, interspersed with minor episodes of compression. On the Sardinian margin, the dives led to the discovery of a submarine volcano, dated at 12.6 Ma, and composed of shoshonitic andesites with lamprophyre inclusions, and to the characterization of the nature and structure of the underlying basement, consisting of tilted blocks of Hercynian metamorphic and granitic rocks and their sedimentary cover. The sea floor morphology reflects this structure. The other areas of the Sardinia Channel explored, i.e. its southern margin and central ridge, belong to the Calabrian-Peloritanian-Kabylian group (CPK). They are composed of a metamorphic and granitic Hercynian basement deformed during the Alpine orogeny, which is stratigraphically overlain by an Oligo-Miocene detrital cover of Peloritanian or Kabylian type, and tectonically overlain by the so-called “flysch nappe”. Throughout the CPK domain these formations were subjected during the Oligo-Miocene, at ca. 23 Ma ago, to a first denudation event, and during the Tortonian, ca. 10-8 Ma ago, to a second denudation, which has been connected to the opening of the Tyrrhenian basin. Structures, microstructures and thermochronological data indicate relatively low P-T conditions for the extensional deformations: this suggests that these units remained at shallow depths in the Apennine-Maghrebian Orogen, and were relatively preserved from the Messinian erosion. The age (12.5 Ma) and nature of the volcanic sequence in the Sorelles is closely comparable with the calc-alkaline suite of the Galite Archipelago, Tunisia. Thus, the data gathered during the dives in the Sardinia Channel give new constraints to the reconstruction of the kinematic evolution not only of the region, but also to the entire western Mediterranean.
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Bessière, Eloïse, Laurent Jolivet, Romain Augier, Stéphane Scaillet, Jacques Précigout, José-Miguel Azañón, Ana Crespo-Blanc, Emmanuel Masini, and Damien Do Couto. "Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example." BSGF - Earth Sciences Bulletin 192 (2021): 8. http://dx.doi.org/10.1051/bsgf/2021007.
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The long-term Pressure-Temperature-time-deformation (P-T-t-d) evolution of the internal zones of orogens results from complex interactions between the subducting lithosphere, the overriding plate and the intervening asthenosphere. 2-D numerical models successfully reproduce natural P-T-t-d paths, but most orogens are non-cylindrical and the situation is far more complex due to 3-D pre-orogenic inheritance and 3-D subduction dynamics. The Mediterranean orogens are intrinsically non-cylindrical. Their 3-D geometry results from the complex shape of the Eurasian and African margins before convergence and from the dynamics of slab retreat and tearing leading to strongly arcuate belts. More than many other segments, the Betic-Rif belt is archetypal of this behavior. A synthesis of the tectonometamorphic evolution of the Internal Zones, also based on recent findings by our group in the framework of the Orogen Project (Alboran domain, including the Alpujárride-Sebtide and Nevado-Filábride complexes) shows the relations in space and time between tectonic and P-T evolutions. The reinterpretation of the contact between peridotite massifs and Mesozoic sediments as an extensional detachment leads to a discussion of the geodynamic setting and timing of mantle exhumation. Based on new 40Ar/39Ar ages in the Alpujárride-Sebtide complex and a discussion of published ages in the Nevado-Filábride complex, we conclude that the age of the HP-LT metamorphism is Eocene in all complexes. A first-order observation is the contrast between the well-preserved Eocene HP-LT blueschists-facies rocks of the eastern Alpujárride-Sebtide Complex and the younger HT-LP conditions reaching partial melting recorded in the Western Alpujárride. We propose a model where the large longitudinal variations in the P-T evolution are mainly due to (i) differences in the timing of subduction and exhumation, (ii) the nature of the subducting lithosphere and (iii) a major change in subduction dynamics at ∼20 Ma associated with a slab-tearing event. The clustering of radiometric ages obtained with different methods around 20 Ma results from a regional exhumation episode coeval with slab tearing, westward migration of the trench, back-arc extension and thrusting of the whole orogen onto the African and Iberian margins.
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Angrand, Paul, and Frédéric Mouthereau. "Evolution of the Alpine orogenic belts in the Western Mediterranean region as resolved by the kinematics of the Europe-Africa diffuse plate boundary." BSGF - Earth Sciences Bulletin, August 25, 2021. http://dx.doi.org/10.1051/bsgf/2021031.
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The West European collisional Alpine belts are the result of the inversion, initiated in the middle Cretaceous, of the complex western Neotethys and the Atlantic continental rift domains and closure of remnants of Tethys between North Africa and European cratons. While the kinematics of Africa relative to Europe is well understood, the kinematics of microplates such as Iberia and Adria, within the diffuse collisional plate boundary, are still a matter of debate. We review geological and stratigraphic constraints in the peri-Iberia fold-thrust belts and basins to define the deformation history and crustal segmentation of the West European realm. These data are then implemented with other constraints from recently published kinematic and paleogeographic reconstructions to propose a new regional tectonic and kinematic model of the Western Europe from the late Permian to recent times. Our model shows that the pre-collisional extension between Europe and Africa plates was distributed and oblique, hence building discontinuous rift segments between the southern Alpine Tethys and the Central Atlantic. They were characterised by variably extended crust and narrow oceanic domains segmented across transfer structures and micro-continental blocks. The main tectonic structures that are inherited from the late Variscan orogeny localized both rifting and orogenic belts. We show that several continental blocks, including the Ebro-Sardinia-Corsica block, have been key in accommodating strike-slip, extension, and contraction in both Iberia and Adria. Its existence further allows refining the tectonic relationship between Iberia, Europe and Adria in the Alps. By the Paleogene, the convergence of Africa closed the spatially distributed oceanic domains, except for the Ionian basin. From this time onwards, collision spread over the different continental blocks, allowing an efficient transfer of the deformation from Africa to Europe. The area was eventually affected by the West European Rift, in the late Eocene, which may have influenced the opening of the West Mediterranean. The low convergence associated with collisional evolution of Western Europe permits to resolve the control of the inherited crustal architecture on the distribution of strain in collision zone, that is otherwise lost in more mature collision domain such as the Himalaya.
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Dagnino, Davide, Maria Guerrina, Luigi Minuto, Mauro Giorgio Mariotti, Frédéric Médail, and Gabriele Casazza. "Climate change and the future of endemic flora in the South Western Alps: relationships between niche properties and extinction risk." Regional Environmental Change 20, no. 4 (October 16, 2020). http://dx.doi.org/10.1007/s10113-020-01708-4.
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AbstractClimate change seriously threatens biodiversity, particularly in mountain ecosystems. However, studies on climate change effects rarely consider endemic species and their niche properties. Using species distribution models, we assessed the impact of climate change on the endemic flora of the richest centre of endemism in the Alps: the South-Western Alps. We projected the potential distributions of 100 taxa under both an optimistic (RCP2.6) and a pessimistic (RCP8.5) climate scenario, analysing the relationships between range dynamics and several predictors (dispersal abilities, vegetation belts, niche marginality, niche breadth, altitudinal range and present range). The negative impact ranged from weak to severe according to the scenario, but the extinction risk was low. The dispersal abilities of species strongly affected these range dynamics. Colline and subalpine species were the most threatened and the relationship between range dynamics and predictors varied among vegetation belts. Our results suggest that the rough topography of the SW Alps will probably buffer the climate change effects on endemics, especially if climate will remain within the limits already experienced by species during the Holocene. The presence of the Mediterranean-mountain flora, less affected by climate change than the alpine one, may explain the lower number of species threatened by extinction in the SW Alps than in other European mountains. These results suggest that the relationship between plants’ sensitivity to climate change, and both niche properties and vegetation belts, depends on the difference between the current climate in which species grow and the future climate, and not just on their niche breadth.
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Casalini, Martina, Riccardo Avanzinelli, Simone Tommasini, Claudio Natali, Gianluca Bianchini, Dejan Prelević, Massimo Mattei, and Sandro Conticelli. "Petrogenesis of Mediterranean lamproites and associated rocks: The role of overprinted metasomatic events in the post-collisional lithospheric upper mantle." Geological Society, London, Special Publications, May 11, 2021, SP513–2021–36. http://dx.doi.org/10.1144/sp513-2021-36.
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AbstractHigh-MgO lamproite and lamproite-like (i.e. lamprophyric) ultrapotassic rocks are recurrent in the Mediterranean and surrounding regions. They are associated in space and time with ultrapotassic shoshonites and high-K calc-alkaline rocks. This magmatism is linked with the geodynamic evolution of the westernmost sector of the Alpine–Himalayan collisional margin, which followed the closure of the Tethys Ocean. Subduction-related lamproites, lamprophyres, shoshonites and high-K calc-alkaline suites were emplaced in the Mediterranean region in the form of shallow level intrusions (e.g. plugs, dykes and laccoliths) and small volume lava flows, with very subordinate pyroclastic rocks, starting from the Oligocene, in the Western Alps (northern Italy), through the Late Miocene in Corsica (southern France) and in Murcia-Almeria (southeastern Spain), to the Plio-Pleistocene in Southern Tuscany and Northern Latium (central Italy), in the Balkan peninsula (Serbia and Macedonia) and in the Western Anatolia (Turkey). The ultrapotassic rocks are mostly lamprophyric, but olivine latitic lavas with a clear lamproitic affinity are also found, as well as dacitic to trachytic differentiated products. Lamproite-like rocks range from slightly silica under-saturated to silica over-saturated composition, have relatively low Al2O3, CaO and Na2O contents, resulting in plagioclase-free parageneses, and consist of abundant K-feldspar, phlogopite, diopsidic clinopyroxene and highly forsteritic olivine. Leucite is generally absent, and it is rarely found only in the groundmasses of Spanish lamproites. Mediterranean lamproites and associated rocks share an extreme enrichment in many incompatible trace elements and depletion in High Field Strength Elements and high, and positively correlated Th/La and Sm/La ratios. They have radiogenic Sr and unradiogenic Nd isotope compositions, high 207Pb over 206Pb and high time-integrated 232Th/238U. Their composition requires an originally depleted lithospheric mantle source metasomatized by at least two different agents: (1) a high Th/La and Sm/La (i.e. SALATHO) component deriving from lawsonite-bearing, ancient crustal domains likely hosted in mélanges formed during the diachronous collision of the northward drifting continental slivers from Gondwana; (2) a K-rich component derived from a recent subduction and recycling of siliciclastic sediments. These metasomatic melts produced a lithospheric mantle source characterized by network of felsic and phlogopite-rich veins, respectively. Geothermal readjustment during post-collisional events induced progressive melting of the different types of veins and the surrounding peridotite generating the entire compositional spectrum of the observed magmas. In this complex scenario, orogenic Mediterranean lamproites represent rocks that characterize areas that were affected by multiple Wilson cycles, as observed in the Alpine–Himalayan Realm.
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Рогожин, Е. А., А. Л. Собисевич, Л. Е. Собисевич, and Т. Ю. Тверитинова. "STRUCTURAL POSITION AND THE PROBLEMS OF MUD VOLCANISM CENTERS APPEARANCE IN THE POST ALPINE PLICATED CONSTRUCTION OF THE NORTH-WESTERN CAUCASUS (BASED ON THE EXAMPLE OF THE STUDY OF THE DEEP STRUCTURE OF THE MUD VOLCANO SHUGO)." Геология и геофизика Юга России, no. 3 (September 18, 2014). http://dx.doi.org/10.23671/vnc.2014.3.55453.
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Большинство грязевых вулканов расположено вдоль крупных тектонических зон Средиземномор- ского и Тихоокеанского подвижного поясов. Важным условием грязевулканических процессов являются складчатые деформации и дизъюнктивная дислоцированность осадочных образований. Вулкан Шуго один из наиболее известных действующих грязевых вулканов Таманской грязевулканической провинции в северо-западной периклинальной части альпийского складчатого сооружения Большого Кавказа. На фоне относительно спокойного характера этого грязевого вулкана в 1903, 1908 и 2006 гг. наблюдались кратковременные бурные извержения. Новые геофизические данные о глубинном строении вулкана Шуго расширяют наши представления о механизмах деятельности данного геологического объекта с учётом имеющихся материалов о его структурно-геологической позиции. В ходе полевых работ нами уточнено глубинное строение и получены данные о трещинно-разрывных структурах вулканической постройки, позволяющие перейти к рассмотрению тектодинамических условий формирования вулкана Шуго. The majority of mud volcanoes is located along the large tectonic zones of Mediterranean and Pacific Ocean mobile belts. The important condition for mud volcanoes processes are plicated deformations and disjunctive dislocation of sedimentary formations. Volcano Shugo one of the most known active mud volcanoes of Taman mud volcanoes province in the North-Western periclinal part of the Alpine plicated construction of the Great Caucasus. The volcano has relatively calm nature , but in 1903, 1908 and 2006 yr. short-term stormy eruptions were observed.The new geophysical data about the deep structure of the Shugo volcano enlarge our ideas about the mechanisms of this geological object activity taking into account available material about its structural- geological position. Duringthe field works we have refined its deep structure and acquired data about the interstitial- explosive structures of the volcanic building, which make it possible to pass to the examination of the tekto-dynamical conditions for the formation of the Shugo volcano
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Mouthereau, Frederic, Paul Angrand, Anthony Jourdon, Sébastien Ternois, Charlotte Fillon, Sylvain Calassou, Sébastien Chevrot, et al. "Cenozoic mountain building and topographic evolution in Western Europe: impact of billion years lithosphere evolution and plate tectonics." BSGF - Earth Sciences Bulletin, September 27, 2021. http://dx.doi.org/10.1051/bsgf/2021040.
Full textAbstract:
The architecture and nature of the continental lithosphere result from billions of years of tectonic and magmatic evolution. Continental deformation over broad regions form collisional orogens which evolution is controlled by the interactions between properties inherited from hits long-lasting evolution and plate kinematics. The analysis of present-day kinematic patterns and geophysical imaging of lithosphere structure can provide clues on these interactions. However how these interactions are connected through time and space to control topographic evolution in collision zones is unknown. Here we explore the case of the Cenozoic mountain building and topographic evolution of Western Europe. We first review the tectono-magmatic evolution of the lithosphere of Europe based on the exploitation of geological, geochronological and geochemical constraints from ophiolites, mafic rocks and xenoliths data. Combined with the analyses of low-temperature thermochronological and plate kinematic constraints we discuss the key controlling parameters of the topography. We show that among the required ingredients is the primary effect of plume-, rift- and subduction-related metasomatic events on lithosphere composition. Those main events occurred during the Neoproterozoic (750-500 Ma) and the late Carboniferous-Permian (310-270 Ma). They resulted in the thinning and weakening of the sub-continental lithospheric mantle of Europe. Contrasting lithosphere strengths and plate-mantle coupling in Western Europe with respect to the cratonic lithosphere of West Africa Craton and Baltica is the first-order parameter that explain the observed strain and stress patterns. Subsequent magmatic and thinning episodes, including those evidenced by the opening of the early Jurassic Alpine Tethys and the CAMP event, followed by late Jurassic and early Cretaceous crustal thinning, prevented thermal relaxation of the lithosphere and allowed further weakening of the European lithosphere. The spatial and temporal evolution of topographic growth resolved by the episodes of increased exhumation show two main periods of mountain building. During the late Cretaceous-early Cenozoic (80-50 Ma) contractional deformation was distributed from North Africa to Europe, but the topographic response to the onset of Africa-Eurasia convergence is detected only in central Europe. The lack of rapid exhumation signal in southern Europe and north Africa reveal that the initial continental accretion in these regions was accommodated under water in domains characterized by thin continental or oceanic crust. The second phase of orogenic uplift period starts at about 50 Ma between the High Atlas and the Pyrenees. This second key period reflects the time delay required for the wider rift systems positioned between Africa and Europe to close, likely promoted by the acceleration of convergence. Tectonic regime then became extensional in northern Europe as West European Rift (WER) opened. This event heralds the opening of the Western Mediterranean between Adria and Iberia at ca. 35 Ma. While mature orogenic systems developed over Iberia at this time, the eastern domain around northern Adria (Alps) was still to be fully closed. This kinematic and mechanical conditions triggered the initiation of backarc extension, slab retreat and delamination in the absence of strong slab pull forces. From about 20 Ma, the high temperature in the shallow asthenosphere and magmatism trapped in the mantle lithosphere contributed to topographic uplift. The first period (80-20 Ma) reveals spatially variable onset of uplift in Europe that are arguably controlled by inherited crustal architecture, superimposed on the effect of large-scale lithospheric properties. The second period marks a profound dynamic change, as sub-lithospheric processes became the main drivers. The channelized mantle flow from beneath Morocco to Central Europe builds the most recent topography. In this study, we have resolved when, where and how inheritance at lithospheric and crustal levels rule mountain building processes. More studies focus on the tectonic-magmatic evolution of the continental lithosphere are needed. We argue that when they are combined with plate reconstructions and thermochronological constraints the relative impact of inheritance and plate convergence on the orogenic evolution can be resolved.