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![Sketch map of present-day plate tectonics in the eastern Mediterranean region [after Taymaz et al., 1991; Reilinger et al., 1997; McClusky et al., 2000; Kahle et al., 2000; Taymaz et al., 2007]. The arrows are GPS velocity vectors (mm/a) relative to a reference frame fixed with Eurasia.](profile/Ewald-Hejl/publication/251437584/figure/fig4/AS:759346275303427@1558053668737/Sketch-map-of-present-day-plate-tectonics-in-the-eastern-Mediterranean-region-after.png)
Sketch map of present-day plate tectonics in the eastern Mediterranean region [after Taymaz et al., 1991; Reilinger et al., 1997; McClusky et al., 2000; Kahle et al., 2000; Taymaz et al., 2007]. The arrows are GPS velocity vectors (mm/a) relative to a reference frame fixed with Eurasia.
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We have investigated the low-temperature history of pre-Neogene basement areas adjacent to the western extension of the North Anatolian Fault zone (NAFZ) by apatite fission track thermochronology of 33 samples taken from Marmara island, Kapidag peninsula (both in the Sea of Marmara), Samothrake island, and Chalkidike peninsula (both in the North Ae...
Contexts in source publication
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... The North Anatolian Fault zone is a conspicuous strike-slip system that takes up the westward motion of the Anatolian-Aegean microplate relative to Eurasia (Figure 1). Its dextral sense of displacement was recognized by Ketin [1948] and has been confirmed many times [McKenzie, 1972;Sengör, 1979;Taymaz et al., 1991;Andrieux et al., 1995;Le Pichon et al., 1995;Thatcher, 2009]. ...
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... The present-day North Anatolian Fault zone is composed of two fairly rectilinear branches that join in a northward convex bend (Figure 1). The western extension of the fault system, in the Marmara region and in the adjacent northern Aegean, is divided in two main branches, which are characterized by both dextral strike-slip and normal faulting [Parke et al., 2002;Le Pichon et al., 2003;McNeill et al., 2004;Okay et al., 1999Okay et al., , 2000]. ...
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... velocity fields are useful for determining slip rates on faults and rotation rates of crustal blocks. Indeed, the present-day kinematics of the Aegean, Minor Asia, and the Middle East is very well known from many high-quality GPS measurements ( Figure 1). Le Pichon et al. [1995] have examined plate velocities at seven sites in Anatolia and Aegean to obtain a better definition of the westward escape motion of the Anatolian-Aegean microplate with respect to Europe. ...
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... and references therein. Same colored age symbols as in Figure 18 (orange spots, 10-15 Ma; red spots, 5-10 Ma). seismic profiles and several boreholes for hydrocarbon exploration [cf. ...
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... topography and major faults according to Smith et al. [1995], Okay et al. [2000,2004], Le Pichon et al. [2003], and Laigle et al. [2008]. Same colored age symbols as in Figure 17 (blue spots, 30-35 Ma; turquoise spots, 25-30 Ma; green spots, 20-25 Ma; yellow spots, 15-20 Ma; orange spots, 10-15 Ma). Eleftheriadis et al., 1994]: a low-grade metamorphic basement of Upper Jurassic to Lower Cretaceous argillaceous slates, graywackes, and marbles; ophiolites with gabbros and pillow basalts; a Miocene granitoid intruding the ophiolites and the basement; Upper Oligocene to Lower Miocene volcanic rocks covering the northeast, west and southwest slopes of the island; Neogene to Quaternary sediments along the western and northern shore. ...
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... The standardized estimate 0 on the left-hand side of the radial plot (Figure 10) corresponds to the error-weighted average of all individual ages from Samothrake, i.e., to 11.12 Ma. The radial plot shows clearly that none of the individual ages is consistent with this average within a 2s Figure 9. Results of thermal history calculations for selected samples from Chalkidike peninsula (program AFTSolve, version 0.7.1, © 1996, Donelick analytical, Inc. andRichard A. Ketcham [cf. ...
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... The significance of these age groups is elucidated by a plot of ages versus altitude (Figure 11) and by the geological origin of the samples. The ages of GR 138, 142, 143, 146, and 147 correlate almost perfectly with altitude and cover a time span from 12.7 ± 0.8 to 6.4 ± 0.5 Ma (middle to late Miocene). ...
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... Frequency distributions of confined track lengths from Area B are illustrated by the histograms in Figure 12. For a better comparison with the diagram of age versus altitude, these histograms are arranged in descending order of altitude. ...
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... apatite fission track ages from Samothrake are cooling ages. Consequently, the slope of the regression line of Figure 11 most probably represents a mean exhumation of the involved samples, i.e., an exhumation rate of 140 m/Ma from about 13 to 6 Ma ago (middle to late Miocene), which has affected the central granitoid body of the island. Such fast exhumation could have been provoked by vertical movements along the northern shoulder of the Saros trough, which could have created steep topographies along the edges of the pull-apart system. ...
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... fast exhumation could have been provoked by vertical movements along the northern shoulder of the Saros trough, which could have created steep topographies along the edges of the pull-apart system. The discrepancy between the two age groups could be due to individual blocks, created by transtensional faults, as it is suggested by the profile of Figure 13. Indeed, the higher age group occurs along the shores and in the western part of the island, whereas the group with altitude-dependent ages occurs in the central area. ...
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... Thermochronological modeling of the samples indicates rather fast steady cooling through the whole partial annealing zone between 14 and 10 Ma and a subsequent deceleration of the cooling rate (Figure 14). Cooling was not allowed to be set at a temperature <200°C previous to 18.5 Ma (GR 142 and GR 147) or 18.9 Ma (GR 141 and GR 145), which are the approximate intrusion age of the granitoid plutons and the age of the latest volcanic rocks, according to Pe-Piper and Piper [2002] and Eleftheriadis et al. [1994], respectively. ...
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... The ages obtained for the Kapidag samples range from 31.6 ± 2 Ma to 28.1 ± 1.9 Ma (middle Oligocene). Those obtained for the Marmara samples range from 28 ± Figure 10. Radial plot of apatite fission track ages from Samothrake island (Area B). ...
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... numbers of the dots refer to the Samothrake code of Tables 1 and 2. 3.2 to 26.2 ± 2.3 Ma (late Oligocene). However, this age decrease toward the north has only a very low significance, as can be seen on the radial plot of Figure 15. All ages are situated within the 2s confidence interval and are consistent with the error-weighted average of 29.26 Ma that corresponds to the standardized estimate 0 on the left-hand side of the diagram. ...
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... Frequency distributions of confined track lengths form Area C are visualized by the histograms in Figure 16. High mean track lengths between 13.93 and 14.21 mm and rather low standard deviations between 1.06 and 1.30 mm indicate fast and steady cooling through the whole partial annealing zone. ...
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... Thermochronological modeling of the Marmara island and Kapidag samples indicates fast cooling around 35-25 Ma and subsequent deceleration of the cooling rate (Figure 17). Cooling was not allowed to be set at a temperature <200°C previous to 50 Ma, which corresponds roughly to the climax of the Mesohellenic orogeny and predates the main sediment accumulation in the Thrace basin [cf. ...
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... The regional distribution of available apatite fission track ages within the area of interest is shown in Figure 18. Obviously, the fission track ages are not simply correlated with the horizontal distance from main fault branches of the NAFZ or from corresponding depot centers of pull-apart basins and half-grabens. ...
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... Nevertheless, the regional age pattern is not a random distribution but quite consistent in limited areas and clearly correlated with present-day topography. Steep relief adja- Figure 12. Frequency distributions of confined track lengths of samples from Samothrake island (Area B). ...
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... A graphical representation of apatite fission track ages in ascending order is shown in Figure 19. The measured ages display at least two frequency maxima, i.e., from 35 to 25 Ma and from 17 to 11.5 Ma, the latter being subdivided in two less pronounced submaxima from 17 to 15 and from 14 to 11.5 Ma. ...
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... The answer to the first question has already been given by Zattin et al. [2005] and is confirmed by the new data (compare with Figures 6 and 18). Indeed, significantly different fission track ages were found to the north and to the south of the Ganos fault, which forms a 45 km long linear fault segment crossing Tertiary sediments of the southernmost part of the Thrace basin [cf. ...
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... the Eocene to Oligocene sedimentary rocks to the north of the Ganos fault must have been uplifted along the fault as early as 16 Ma ago (Burdigalian, early Miocene). This is consistent with Figure 13. Simplified geological profile perpendicular to the longitudinal axis of the Saros Trough, between Samothake and Gökceada islands. ...
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... The island of Samothrake is also situated to the north of the NAFZ, just like the Ganos monocline, but in contrast to the latter it forms the northern shoulder of the still active pull-apart basin of the Saros trough (Figures 2 and 13). A strong dip-slip component of present-day movements along the southern shore of the island can be deduced from submarine topography [cf. ...
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... case of a tectonically stable coast, i.e., without vertical rock movements relative to the sea level, one would expect that sustained wave action would create a scoured hallow under the cliff and an abrasion platform with gentle inclination toward the open sea. Such typical coast profile, which can be created by cliff retreat within few Figure 14. Results of thermal history calculations for selected samples from Samothrake island (program AFTSolve, version 0.7.1, © 1996, Donelick analytical, Inc. and Richard A. Ketcham [cf. ...
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... Samothrake's apatite fission track ages are consistently younger than the emplacement of both plutonic and volcanic rocks of the island (compare with Figure 5). For this reason and because of the frequency distributions of confined track lengths (Figure 12), these fission track ages can be considered as cooling ages to about 100°C. The higher age group between 13.6 ± 0.7 Ma and 13.1 ± 0.7 Ma is an indication for the minimum age of transtensional uplift and tilting along the northern shoulder of an early pull-apart basin or half-graben that gave rise to the Saros trough. ...
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... the scenario can be specified by an additional consideration. The second age group of Samothrake, between 12.7 ± 0.8 and 6.4 ± 0.5 Ma, which correlates with altitude, defines a regression line with a slope of 135 m/Ma (Figure 11). Under the assumption of steady exhumation at constant rate and under a constant geothermal gradient until present, the extrapolation of this line to the hypothetical depth of the age zero should correspond to the present-day position of the 100°C isotherm. ...
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... Apatite fission track ages of the North Sporades range from 21.6 ± 1.1 Ma to 7.1 ± 0.6 Ma [Hejl et al., 1999]; those from adjacent mainland (Mount Ossa, Pelion, Volos) range from 19.2 ± 3.2 Ma to 10.3 ± 0.7 Ma [Hejl et al., 2008]. These ages cover almost the entire Miocene and do not belong to the elder age group of late Mesohellenic cooling ages (35-25 Ma, according to Figure 19). However, their causal relation with the development of the North Aegean basin is not obvious at once. ...
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... their causal relation with the development of the North Aegean basin is not obvious at once. On the basis of geomorphological mapping and thermal history calculations from fission track data, Riedl [1998] and Hejl et al. [1999] have demonstrated a stepwise relief development on the islands Figure 18. Regional synopsis of apatite fission track ages. ...
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... fault propagation from east to west becomes probable. Such stepwise fault propagation from east to west is reflected by the two submaxima in age frequency, i.e., 17-15 Ma and 14-11.5 Ma (Figure 19) and by the results of thermal history calculations (section 5). The modeled cooling paths of Samothrake indicate fast cooling between 14 and 10 Ma, i.e., slightly later than the fast cooling of the Ganos monocline in southwestern Thrace [Zattin et al., 2005] but distinctly earlier than the late to post-Miocene accelerated cooling of North Sporades [Hejl et al., 1999]. ...
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... the enormous deepening of submarine basins in the Sea of Marmara [cf. Rangin et al., 2004;Laigle et al., 2008] and to the south of Samothrake must have occurred later, i.e., in Pliocene and Quaternary times, as has been demonstrated by Figure 19. Graphical representation of apatite fission track ages in ascending order of the measured ages and with 2s error bars. ...
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... If transtension along the western segment of the NAFZ was caused or at least facilitated by gravitational retreat of the subducting Eastern Mediterranean oceanic slab along the Hellenic trench [Flérit et al., 2004;Taymaz et al., 1991], then the timing of early North Aegean and Marmara transtension should correlate with the progress of subduc- Figure 20. (a) Sketch map of present-day plate tectonics in the eastern Mediterranean region (Figure 19) with regional distribution of post-Eocene apatite fission track age groups, as reported in this article (Figures 4, 5, 6, and 18) and by (1) Hejl et al. [2008], (2) Thomson et al. [1998], (3) Boztug and Jonckheere [2007], and (4) Okay et al. [2010]. (b) The enlarged area shows the position of the South Aegean Active Volcanic Arc (SAAVA), the ages of the earliest volcanic rocks at the volcanic centers of Methana-Aegina (MET), Milos (MIL), Santorini (SAN), and Kos (KOS), and the distances of these centers from the Hellenic Trench, when the distance is measured parallel to the subduction vector of western Crete. ...
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... we add these time gaps to the age of the earliest volcanic rocks of the corresponding centers, we obtain 12.6 Ma for Methana-Aegina, 11.3 Ma for Milos, 10.1 Ma for Santorini-Christiana, and 14.3 Ma for Kos, which can be interpreted as age estimates for the onset of subduction along the Hellenic trench. Apart from the estimate for Santorini-Christiana, these values coincide quite well with the youngest frequency maximum of fission track ages along the western extension of the NAFZ (Figure 19) and with the onset of rapid exhumation and cooling on Samothrake, as it was demonstrated by thermal history calculations of fission track data ( Figure 14). The melted material that gave rise to the earliest volcanic rocks of SAAVA has probably been subducted along the trench as early as in middle Miocene times. ...
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... we add these time gaps to the age of the earliest volcanic rocks of the corresponding centers, we obtain 12.6 Ma for Methana-Aegina, 11.3 Ma for Milos, 10.1 Ma for Santorini-Christiana, and 14.3 Ma for Kos, which can be interpreted as age estimates for the onset of subduction along the Hellenic trench. Apart from the estimate for Santorini-Christiana, these values coincide quite well with the youngest frequency maximum of fission track ages along the western extension of the NAFZ (Figure 19) and with the onset of rapid exhumation and cooling on Samothrake, as it was demonstrated by thermal history calculations of fission track data ( Figure 14). The melted material that gave rise to the earliest volcanic rocks of SAAVA has probably been subducted along the trench as early as in middle Miocene times. ...
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The construction of mountain belts by continent-continent collision is a fundamental phase of the supercontinent cycle and an inevitable consequence of subduction-driven plate tectonics on Earth. Yet, quantitative estimation of the rate and duration of prograde orogenic metamorphism in high-grade collisional belts has proven elusive to constrain. D...
Citations
... Vitrinite reflectance values also exhibit a sudden decrease above the Hamitabat Formation (Huvaz et al., 2005). These observations indicate a Zattin et al. (2010), and Hejl et al. (2010). The paleo-current data are from Şenol (1980), d 'Atri et al. (2012), and Cavazza et al. (2013). ...
Some orogenic sedimentary basins are difficult to assign to a particular category. An example is the hydrocarbon‐bearing Thrace Basin in the northern Aegean. It has more than 9‐km‐thick Cenozoic clastic sediment, and is spatially associated with the Rhodope metamorphic core complex in the west, and with the Tethyan subduction‐accretion complexes in the south, and is cut by the North Anatolian Fault and its precursors. It has been interpreted variously as an intramontane, a forearc, or an orogenic collapse basin. Here, we provide new geochronological and biostratigraphic data to constrain the tectonic evolution of the Thrace Basin. The new data indicate that as an individual depocenter the Thrace Basin has a short age span (late Eocene—Oligocene, 36–28 Ma) and more than 90% of the basin fill consists of early Oligocene (34–28 Ma) siliciclastic turbidites, deposited at rates of 1.0 km/my. Paleocurrents and new detrital zircon U‐Pb ages show that the Rhodope Complex was the main sediment source. The exhumation of the northern Rhodope Complex (36–28 Ma) was coeval with the main subsidence in the Thrace Basin (34–28 Ma), and involved clockwise crustal rotation in the northern Aegean and possibly crustal flow from underneath the Thrace Basin. Crustal rotation is indicated by the paleomagnetic data, regional stretching lineations in the Rhodope Complex, and the triangular shape of the Thrace Basin. The rotating crustal block must have been bounded in the south by a sinistral fault zone; the location of which corresponds largely with the present day North Anatolian Fault.
... The Karakoram fault zone in southwestern Tibet is known to have had several active fault strands throughout its history with varying amounts of slip occurring along each of these structures (e.g., Dunlap et al., 1998;Phillips et al., 2004;Searle, 1996). The North Anatolian fault zone in Turkey provides another example of a major strike-slip fault system consisting of multiple active branches (e.g., Hejl et al., 2010;Okay et al., 1999). Yet another well-known example would be the San Andreas fault system, which consists of over a dozen faults that all record distinct but often overlapping slip histories (e.g., Scharer & Streig, 2019). ...
The Great Slave Lake shear zone (GSLsz) is a type example for deeply eroded continental transform boundaries located in the Northwest Territories, Canada. Formed during the oblique convergence of the Archean Rae and Slave cratons, the GSLsz has accommodated up to 700 km of dextral shear. Here we present the results of in situ U‐Pb apatite and titanite geochronology from 11 samples that were collected across the strike of the shear zone. Both geochronometers record a near‐continuous history of ductile shear during crustal cooling and exhumation that spans ca. 1920–1740 Ma. By integrating the geochronological data with structural and metamorphic observations across the structure, we propose a tectonic model for the shear zone that consists of three stages. The first stage (ca. 1920–1880 Ma) is characterized by strain accommodation along two coeval fault strands. During the second stage (ca. 1880–1800 Ma), ductile shear ceases along the northernmost fault strand and the locus of strain migrates southwards toward the hinterland of the Rae cratonic margin. In the third stage (ca. 1800–1740 Ma), ductile strain localizes back along the southern of the two original fault strands, after which the present‐day surface level of the shear zone transitions to brittle shear. Our results highlight both the significance of the lateral migration of the zone of active deformation in major crustal shear zones as well as the localization of strain along existing crustal structures.
... Apatite of both phyllite of the Preveli nappe (Thomson et al. 1999) and late Jurassic blueschists of the north Aegean domain (e.g. Chalkidiki, Hejl et al. 2010, Kydonakis et al. 2014central Rhodope, Wüthrich 2009) yielded Eocene fission-track ages at ca. 30 Ma. ...
Concerning their provenance and age, the nappes of the Uppermost Unit of Crete are counted among the most enigmatic constituents of the Eastern Mediterranean. U–Pb dating of zircons separated from metavolcanic rocks of the Preveli nappe exposed near Lefkogia yielded Triassic emplacement ages at 237.3 ± 1.8, 241.5 ± 1.2 and 242.1 ± 1.2 Ma. U–Pb grandite dating of subvolcanic barren skarn of this area yielded the same age at 239.3 ± 2.3 Ma. The skarn is dominated by hydrous phases (ferri-actinolite, hydro-grandite, epidote), which developed at T = 400–450 °C in a marine extensional setting due to fluid-assisted metasomatic reactions between chert-bearing limestone and igneous veins. The fluids and their composition played a significant role for the complex oscillatory zoning of the grandite, which largely results from antithetic variations in Fe3+ and Al. The new U–Pb ages suggest that—similar to deep-seated skarns—U–Pb grandite dating of shallow-seated skarns allows dating the complementary record of hydrothermal activity related to the causative melt. Although the development of skarn is regarded as a short-lived process on geological time scales, the skarn formation of the Preveli nappe lasted for more than 20 m.y. as is indicated by additional U–Pb grandite ages obtained from skarn exposed near Kerames (232.7 ± 1.5 Ma) and near Gerakari (218.0 ± 3.5 Ma). The new ages and published data suggest the Uppermost Unit of Crete to be derived either from the peri-Rhodope domain of the Internal Hellenides or from the Pontides of northern Turkey.
... Hubert-Ferrari et al., 2003). Hejl et al., 2010et Jolivet et al., 2013. Les triangles sont sur le bloc supérieur des chevauchements. ...
... Ce travail de thèse démontre l'intérêt porté au domaine Nord Eubée en tant que zone clef dans le prolongement de la Faille Nord-Anatolienne. La poursuite des études va principalement se faire à travers (1) l'analyse de l'ensemble des données sismiques et bathymétriques acquises au cours de la campagne WATER 2 et (2) Hejl et al., 2010et Jolivet et al., 2013. Les triangles sont sur le bloc supérieur des chevauchements. ...
Le domaine égéen est le théâtre de nombreux évènements géodynamiques importants depuis le Trias. Ces phases de divergence et de convergence n’ont cessé de façonner le paysage, la croûte et le manteau lithosphèrique de la Méditerranée orientale. Aujourd’hui, il en résulte la microplaque Anatolie-Égée, bordée par la Faille Nord-Anatolienne, la Plaque Arabe, les Hellénides et la subduction de la Plaque Afrique sous l’Égée. La migration de cette subduction vers le sud depuis l’Éocène a entraîné l’étirement et l’amincissement de la croûte égéenne, formant des Metamorphic Core Complexes et des rifts. Les contraintes extensives actuelles sont localisées dans ces rifts, comme ceux de Corinthe et du Sperchios-Golfe Nord Eubée en Grèce continentale. Ce dernier, ainsi que l’Eubée du nord, le Chenal d’Oreoi et le Bassin de Skopelos, se situent dans le prolongement occidental de la terminaison de la Faille Nord-Anatolienne qui marque la limite de plaques entre l’Eurasie au nord et l’Anatolie-Égée au sud. Ces zones constituent le domaine Nord Eubée, une région clef dans la compréhension de la déformation entre l’Eurasie et le domaine égéen. L’objectif de cette thèse est ainsi de caractériser la déformation à terre et surtout en mer afin de replacer le domaine Nord Eubée dans le contexte de la Grèce continentale, à l’échelle de cette limite de plaques diffuse. Ces travaux reposent sur l’interprétation de nouvelles données de sismique réflexion très haute résolution (Sparker) acquises au cours des campagnes à la mer « WATER » 1 et 2. L’étude globale a été divisée en deux étapes principales : (1) l’analyse des structures au sein du domaine Nord Eubée et (2) la caractérisation de la déformation actuelle de ce domaine et son évolution depuis l’initiation du rifting.L’interprétation des profils Sparker a permis d’établir une carte tectonique détaillée qui a ensuite été intégrée au contexte régional de déformation grâce à la compilation des données structurales publiées à terre. Cette carte met en évidence quatre directions de failles : NE-SW, NW-SE, WNW-ESE et W-E à travers l’ensemble du domaine Nord Eubée. Ces directions ont été mises en perspective avec les rotations horaires enregistrées proche du rift, permettant ainsi de proposer un nouveau modèle chronologique pour le domaine Nord Eubée depuis le début de la formation du rift. La dernière étape de ce modèle rend compte de la situation actuelle qui est marquée par de nombreux séismes de magnitudes comprises entre 4 et 7 et de nombreux mécanismes aux foyers associés à ces séismes. L’interprétation de ces mécanismes aux foyers met en exergue des mouvements décrochants dextres le long des failles orientées NE-SW et des déplacements sénestres le long des failles orientées NW-SE. La déformation actuelle du domaine Nord Eubée rend compte de la complexité d’une part, des réseaux de failles qui semblent tous actifs et, d’autre part, de la déformation au sein de cette limite de plaques diffuse où la Faille Nord-Anatolienne pourrait avoir une influence sur les rotations horaires et les failles orientées NE-SW. Le rift Sperchios-Golfe Nord Eubée a été replacé dans le contexte de la Grèce continentale notamment à partir de deux coupes à l’échelle crustale tracées entre le Péloponnèse et l’Eubée. Ces coupes montrent les asymétries des rifts de Corinthe et du Sperchios-Golfe Nord Eubée et leurs relations avec les variations d’épaisseur de la croûte. Ainsi, les parties occidentales des deux rifts semblent être contrôlées en profondeur par des structures à faible pendage vers le nord, un détachement pour Corinthe et le Front de Chevauchement Pélagonien pour le Sperchios-Golfe Nord Eubée. À l’ouest, le Moho est plus profond sous les rifts et il remonte à l’aplomb des reliefs situés au nord de chacun des rifts, ainsi les rifts et la croûte montrent une forte asymétrie. À l’est, les remontées de Moho sont localisées sous les rifts et l’ensemble de la structure semble symétrique.
... Karacık et al., 2008;Ustaömer et al., 2009;Karslı et al., 2011;Altunkaynak et al., 2012;Ersoy and Palmer, 2013;Topuz and Okay, 2017). During Oligocene time a regional exhumation took place (Hejl et al., 2010;Cavazza et al., 2012) and the whole of the Pontides, except the westernmost part (northern and eastern part of the Thrace basin; Less et al., 2011;Okay et al. 2019), was uplifted above sea level. Thus, the Eocene sediments represent the last marine deposits in most of the Pontides. ...
The Ekmekçi granodiorite porphyry is a member of the E-W trending, post-collisional Eocene magmatic rocks of the northern Anatolia. It occurs as a relatively small stock, but represents a link between the plutonic and the volcanic rocks. This Early Eocene granodiorite porphyry is intruded into the Upper Triassic rocks of the Karakaya complex of the Sakarya Zone. In this study we present geochemical and zircon U–Pb LA-ICPMS age data to contribute to Early Tertiary post-collisional tectonic setting of NW Anatolia.
The granodiorite porphyry includes plagioclase, quartz, hornblende, K-feldspar, biotite, and minor zircon, apatite, sphene, and opaque mineral. The stock displays medium-K calc-alkaline I-type, and metaluminous affinity. Similar to other Eocene magmatic rocks, it displays characteristic features of subduction-related magmatism, such as enrichment in large ion lithophile elements (LILE) relative to high-field strength elements (HFSE) and enrichment of light rare earth elements (LREE) relative to the heavy rare earth elements (HREE) with a lack of significant Eu anomalies. They are characterized by homogeneous initial Sr and Nd isotopic compositions of 0.7044 - 0.7049 and 0.51255 - 0.51260, respectively. Zircon U-Pb data indicate that the Ekmekçi granodiorite porphyry was emplaced at 50.9 ± 1.2 Ma (Ypresian). Geochemically, the Ekmekçi granodiorite porphyry is similar to the mafic volcanic rocks rather than to the plutonic rocks of thesame age. It was emplaced to the north of the İzmir-Ankara-Erzincan Suture (northern plutonic belt of the NW Anatolia), and can be correlated with the southern plutons such as Orhaneli, Topuk, Tepeldağ, Gürgenyayla, and Sivrihisar on the Anatolide-Tauride block in terms of age.
... U-Pb zircon ages of the adjacent İlyasdağ pluton (Marmara Island) and Karabiga pluton (near Biga) yielded emplacement ages of 47.6 ± 2 Ma (Ustaömer et al. 2009) and 47.0 ± 1 Ma (Altunkaynak et al. 2012), respectively. Apatite fission-track ages obtained from granitoids of the southern part of the Kapıdağ Peninsula range from 28 ± 2 to 32 ± 2 Ma (Hejl et al. 2010). Aksoy (1998) The Kapıdağ shear zone, as mapped by Aksoy (1998) along the northern coast of the Kapıdağ Peninsula, extends almost E-W from Rikoz Cape in the west, via just south of Doğanlar, Turan, Ormanlı, Ballıpınar, Çayağzı and Kestanelik villages, toward the north of Çakıl village in the east (Fig. 2). ...
... Apatite fission-track ages obtained from the southern Kapıdağ Peninsula (30.6 ± 1.9 and 31.6 ± 2.0 Ma; Hejl et al. 2010) are similar to those determined from the Marmara island (31-23 Ma; Hejl et al. 2010). Thus, in the Oligocene, the rocks exposed today in the study area and surroundings should have been situated at uppermost structural levels where T < ca. 100 °C (Fig. 10). ...
... Apatite fission-track ages obtained from the southern Kapıdağ Peninsula (30.6 ± 1.9 and 31.6 ± 2.0 Ma; Hejl et al. 2010) are similar to those determined from the Marmara island (31-23 Ma; Hejl et al. 2010). Thus, in the Oligocene, the rocks exposed today in the study area and surroundings should have been situated at uppermost structural levels where T < ca. 100 °C (Fig. 10). ...
The northern part of the Kapıdağ Peninsula (Marmara Sea, NW Turkey) is affected by the E–W trending Kapıdağ shear zone, which cuts through calc-alkaline granitoids of the Ocaklar pluton resulting in mylonitic orthogneiss. Macroscopic and microscopic shear-sense indicators, such as SC fabrics, shear bands, σ-clasts and mica fish, unequivocally suggest dextral strike-slip for the Kapıdağ shear zone. Based on petrographic data, deformation microfabrics of quartz and feldspar, and the slip systems in quartz, the dextral shearing should have been active at T = 500–300 °C and P < 5 kbar. Published K–Ar and 39Ar–40Ar cooling ages of hornblende and biotite suggest that cooling below 500–300 °C occurred during the Eocene (ca. 45–ca. 35 Ma), meaning that the Kapıdağ shear zone should have been active during Middle to Late Eocene times. The differential stress related to the shearing was <50 MPa as is indicated by the size of recrystallized quartz grains. Based on the new and published data, it is concluded that the westward movement of the Anatolian plate might have been active almost continuously from the Middle Eocene until recent times.
... See also Figure 5 for Cenozoic faults in SW Bulgaria. Thermochronology data are fission track ages from Hejl et al. [2010] and Kounov et al. [2015] in the Vrondou and Symvolon massifs of northern Greece and new (U-Th-Sm)/He data in SW Bulgaria. See Figure 4a for sample locations and age data from this study. ...
... Both the kernel smoothing functions of all bedrock ages (dashed red) and the outlier-corrected bedrock data set (solid red) have a narrow peak at~16.5 Ma, i.e., older than >80% of the detrital ages from both samples. Mean ages ± 1 SD for the data sets are 16.6 ± 1.7 Ma for the outlier-corrected bedrock data and 13.2 ± 2.9 Ma (13BG14) and 14.0 ± 2.8 Ma (13BG05) for the detrital samples excluding four data points >25 Ma (Figure 4d). Figure 4e combines our new (U-Th-Sm)/He data with published apatite and zircon fission track ages from the footwall of the Strymon detachment in the southern SRCC ( Figure 2) [Hejl et al., 2010;Kounov et al., 2015]. ...
... Equilibrated rivers that flow through uniform lithology are expected to show constant channel steepness and a simple concave-up form along the course of the river. Variations in channel steepness may result, for example, from lithological variations, i.e., erodibility of the channel bed, or variable tectonic uplift rates, i.e., offset in uplift rates across a fault, regional tilting, or a change in uplift rate or base level within the time frame of geomorphic response [Whipple and Tucker, 1999 Figure 2) [Hejl et al., 2010;Kounov et al., 2015]. Zircon (U-Th)/He and fission track ages are also shown as diamonds with black outline. ...
Upper crustal extensional structures range from steep normal faults to shallow-dipping detachments. The relationship between extension and formation of synkinematic hanging wall basins including their relative timing is not well understood. The South Rhodope core complex, Southern Balkans, has experienced extension for >40 Ma leading to a number of extensional structures and Cenozoic sedimentary basins. We present new bedrock and basin detrital zircon and apatite (U-Th-Sm)/He ages from the Pirin and Rila Mountains and the Sandanski basin. Results identify three episodes of Cenozoic extension in SW Bulgaria accommodated by (1) the Eocene/Oligocene Mesta detachment; (2) the early to middle Miocene Gorno Spanchevo fault (circa 18–15 Ma), which is the northern prolongation of the Strymon low-angle detachment; and (3) the late Miocene West Pirin fault (≤10 Ma). Detachment faulting on the Strymon fault accommodated tens of kilometers of ENE-WSW extension and created ~1500 m topographic relief, but because the resulting hillslopes were gentle (≤10°), extension did not lead to enhanced footwall erosion or formation of a hanging wall basin. In contrast, the West Pirin normal fault resulted in mostly vertical motion of its footwall causing steep topography, rapid erosion, and formation of the synrift Sandanski basin. Digital topographic analysis of river channel profiles identifies the latest episodes of deformation including westward tilting of the Sandanski and Strymon basins and Quaternary N-S extension. This study demonstrates that basin formation in the South Rhodope core complex is related to normal faulting postdating the main episode of crustal stretching by detachment faulting.
... Widespread Jurassic-Cretaceous metamorphic ages [Reischmann and Kostopoulos, 2002;von Quadt et al., 2008von Quadt et al., , 2009Krenn et al., 2010;Nagel et al., 2011;Liati et al., 2011, and references therein], roughly corresponding to eclogites-facies peak event and subsequent amphibolite-facies overprint, have been described for the whole domain in the literature. The final unroofing, as estimated by low-temperature thermochronology, for the central and northeastern parts is well defined at Eocene-Miocene [e.g., Hejl et al., 1998Hejl et al., , 2010Wuthrich, 2009]. Regardless, the cooling history of the westernmost part of the Rhodope Metamorphic Province, known as the Serbo-Macedonian Domain, remains poorly constrained. ...
... Red thick line is used for the thermal path of the hottest (lowest-elevation) sample (red thin lines 95% credible interval range) and blue thick line for the thermal path of the coolest (highest-elevation) sample (blue thin lines 95% credible interval range). Using the same modeling approach and the samples GR117, GR126, GR132, and GR134 from Hejl et al. [2010], we calculated, for comparison, the thermal path of the lower Eocene Sithonia pluton from the southern edge of the Chalkidiki peninsula (see Figure 1 for location). (bottom) The corresponding FT age (blue), mean track length (red), and kinetic parameter (green) predictions for the constrained and nonconstrained models are shown. ...
... The cooling path crosses the high-temperature limit of the apatite FT partial annealing zone (~120°C) at uppermost Cretaceous (between 62 and 70 Ma) and remains at temperature <50°C since the lower Eocene. Using the available geochronology data [Hejl et al., 2010] for a typical Lower Eocene pluton of the first magmatic pulse (Sithonia pluton from the southern tip of the Chalkidiki peninsula; Figure 1) and the profile modeling technique described in a previous section, we can demonstrate that this pluton cooled to 50°C as early as lowermost Oligocene (~33 Ma), i.e., 10-15 Myr later than the surrounding basement rocks (Figure 6). Thus, it can be concluded that none of the two magmatic pulses penetrating the Vertiskos Unit (Eocene and Oligo-Miocene) were strong enough to cause regional thermal perturbations. ...
The Vertiskos Unit of northern Greece is an elongated basement belt with a complex poly-metamorphic history. It extends from Greece (Chalkidiki peninsula), to the south, up to Serbia, in the north, and arguably represents the westernmost part of the Rhodope Metamorphic Province (northern Greece – southern Bulgaria). The Vertiskos Unit experienced a medium pressure lower amphibolite-facies metamorphic overprint during the Alpine Orogeny. The available medium-temperature geochronology implies that it remained at temperature of ca. 300 °C (or slightly higher) during Lower Cretaceous. In order to constrain its post-Lower Cretaceous thermal history, until near surface exposure, we applied apatite fission-track analysis. The central ages obtained range from 68.5 ± 3.8 to 46.6 ± 3.6 Ma (uppermost Cretaceous to Middle Eocene) and mean track lengths between 13 and 13.5 µm. We applied two inverse thermal modelling approaches using either each sample independently (high degree of freedom in the thermal history, better data fit) or all samples together interpreting them as a vertical profile (simpler thermal history, worse data fit). Irrespective of the modelling approach, we conclude that the bulk thermal history of the Vertiskos Unit crosses the high-temperature limit of the apatite partial annealing zone by the uppermost Cretaceous and reaches near-surface conditions as early as Lower/Middle Eocene. These results contrast with the thermal history of the other domains of the Rhodope Metamorphic Province further east (namely the Southern Rhodope Core Complex and the Northern Rhodope Complex) and establish the Vertiskos basement complex as the oldest exhumed coherent basement fragment of the Rhodope Metamorphic Province and Greece.
... Although the Kestanbol zircon is affected by analytical error, the young Kozak grain displays zoning consistent with metamorphism and alteration as evidenced by microcracks and darker swirls within the grain itself (Fig. 6E). The 17-18 Ma zircon ages reported here are similar to fission track ages from NASZ rocks that suggest early propagation of the structure in the region at this time (Hejl et al., 2010). Paleomagnetic data and 40 Ar/ 39 Ar geochronology suggest Late Miocene NASZ activity along structures that transect or may affect the Kestanbol pluton (Kaymakci et al., 2007) The same dating technique used in this study has been applied to zircons in granitoids from the Northern Menderes Massif (Eğrigöz, Koyunoba, and Alaçam plutons) located south of the İAESZ in the Anatolide-Tauride block (Catlos et al., 2012). ...
The Biga Peninsula of NW Turkey hosts granitoid plutons that record the timing of extension in the Aegean re-gion. Here we focus on three plutons, the Kozak, Eybek, and Kestanbol and apply new methods to obtain a de-tailed tectonic history of their generation and exhumation. In situ (in thin section) ion microprobe zircon geochronology and color cathodoluminescence (CL) imaging of zircon grains and whole thin sections show these granites experienced magma mixing, brittle deformation, and significant fluid-rock interactions. Zircon ages range from the Late Eocene to Late Miocene with two ages from a single grain that are Permian. The Late Eo-cene–Early Oligocene ages record the end stages of subduction during the closure of a branch of the Neo-Tethyan Ocean, whereas Late Oligocene–Late Miocene ages record the plutons' extension and exhumation. We present a model in which Kozak, Eybek, and Kestanbol magmas were initially generated by fluid-flux melting from dehy-dration of the subducting Anatolide–Tauride block, as evidenced by the Late Eocene to Early Oligocene ages. Late Oligocene ages document the initiation of extension in the Biga Peninsula region and correlate to ages timing ex-humation of the Kazdağ Massif. Early Miocene ages indicate continued Aegean extension in the southern Biga Peninsula region at this time.
... [3] Here, the thermal sensitivity of (U-Th-Sm)/He and apatite FT systems to low-temperatures between 40 -80 C and $60 -120 [e.g., Green et al., 1986;Farley, 2000] provides a unique perspective for fault dating. Most apatite based thermochronological estimate studies estimate fault ages indirectly by comparing the cooling histories of the foot and hanging wall sections across major faults [e.g., Ehlers and Farley, 2003;Redfield et al., 2005;Seiler et al., 2010;Hejl et al., 2010]. Past attempts to directly date heat transfer along faults by apatite FT and (U-Th-Sm)/He data were usually less successful. ...
The brittle structural inventory of southern and southwestern Sri Lanka
has been studied by kinematic, mineralogical and thermochronological techniques.
Thermochronological analyses of faults comprise apatite and zircon fission track
(FT) data and apatite (U-Th-Sm)/He ages from fault planes and undisturbed host rocks,
and range between �65 and �230 Ma. The ages of both settings are undistinguishable
for topographic altitudes below �100 m, while fault planes from higher elevations
are significantly younger than the corresponding host rocks. Thermal history modeling
and qualitative interpretation of the thermochronological data identify at least five episodes
of thermal overprint associated with faulting activity occurring at 159 � 18,
144 � 14, 120 � 10, 94 � 8, and 70 � 10 Ma. The kinematic, mineralogical
and thermochronological data collectively show that Sri Lanka was subjected to
major N-S oriented extension subsequent to the Gondwana breakup. The resulting brittle
structures exert primary control on the island’s geomorphology, especially on the
Southern Escarpment of the Sri Lankan Highlands.
