TY - JOUR A1 - Akal, Cuneyt A1 - Koralay, O. Ersin A1 - Candan, Osman A1 - Oberhänsli, Roland A1 - Chen, Fukun T1 - Geodynamic significance of the early triassic karaburun granitoid (Western Turkey) for the opening history of Neo-Tethys JF - Turkish journal of earth sciences = Türk yerbilimleri dergisi N2 - The Karaburun Peninsula, which is considered part of the Anatolide-Tauride Block of Turkey, contains clastic and carbonate sequences deposited on the northern margin of Gondwana. The Palaeozoic clastic sequence, which is intruded by the Early Triassic granitoid and tectonically overlies a Mesozoic melange sequence, can be divided into three subunits: a lower clastic subunit consisting of a sandstone-shale alternation, an upper clastic subunit consisting of black chert-bearing shales, sandstone and conglomerate, and a Permo-Carboniferous carbonate subunit. The lower Triassic Karaburun I-type granitoid has a high initial Sr-87/Sr-86 ratio (0.709021-0.709168), and low Nd-143/Nd-144 ratio (0.512004-0.512023) and epsilon Nd (-5.34 to -5.70) isotopic values. Geochronological data indicate a crystallization (intrusion) age of 247.1 +/- 2.0 Ma (Scythian). Geochemically, the acidic magmatism reflects a subduction-related continental-arc basin tectonic setting, which can be linked to the opening of the northern branch of Neo-Tethys as a continental back-arc rifting basin on the northern margin of Gondwana. This can be related to the closure through southward subduction of the Palaeotethys Ocean beneath Gondwana. KW - Karaburun KW - Neo-Tethys KW - Palaeo-Tethys KW - diorite KW - Triassic KW - magmatism Y1 - 2011 U6 - https://doi.org/10.3906/yer-1008-1 SN - 1300-0985 VL - 20 IS - 3 SP - 255 EP - 271 PB - Tübitak CY - Ankara ER - TY - JOUR A1 - Akal, Cüneyt A1 - Candan, Osman A1 - Koralay, O. Ersin A1 - Oberhänsli, Roland A1 - Chen, Fukun A1 - Prelevic, Dejan T1 - Early Triassic potassic volcanism in the Afyon Zone of the Anatolides/Turkey - implications for the rifting of the Neo-Tethys JF - International journal of earth sciences N2 - Afyon Zone, which was derived from the Anatolide-Tauride platform during closure of the Neo-Tethys, is made up of pre-Mesozoic basement and unconformably overlying Triassic-Early Tertiary cover series. The Afyon Zone contains widespread metavolcanic rocks, which are dominated by rhyolite, dacite, and trachyandesite. They form a distinct volcanic succession, which is separated from the underlying Silurian-Lower Carboniferous metacarbonates and meta-siliciclastics by a regional unconformity. Trachyandesitic metavolcanics are made up of massive lava flows, pyroclastics and epiclastics, less frequently, domes and dikes, which were developed on a deeply eroded subaerial landmass. U/Pb and Pb/Pb zircon geochronology yielded Lower Triassic (similar to 250 Ma) ages, which are interpreted as extrusion age of trachyandesitic volcanics. Based on the stratigraphic, geochronological, and geochemical data, we suggest that these Lower Triassic magmatic rocks represent an extensional tectonic setting on the northern active margin of the Gondwana, which led to the development of the northern branch of the Neo-Tethys. KW - Meta-trachyandesite KW - Afyon Zone KW - Turkey KW - Neo-Tethys KW - Paleo-tethys Y1 - 2012 U6 - https://doi.org/10.1007/s00531-011-0654-2 SN - 1437-3254 VL - 101 IS - 1 SP - 177 EP - 194 PB - Springer CY - New York ER - TY - JOUR A1 - Cetinkaplan, Mete A1 - Pourteau, Amaury A1 - Candan, Osman A1 - Koralay, O. Ersin A1 - Oberhänsli, Roland A1 - Okay, Aral I. A1 - Chen, Fukun A1 - Kozlu, Huseyin A1 - Sengun, Firat T1 - P-T-t evolution of eclogite/blueschist facies metamorphism in Alanya Massif: time and space relations with HP event in Bitlis Massif, Turkey JF - International journal of earth sciences N2 - The Alanya Massif, which is located to the south of central Taurides in Turkey, presents a typical nappe pile consisting of thrust sheets with contrasting metamorphic histories. In two thrust sheets, Sugozu and GundogmuAY nappes, HP metamorphism under eclogite (550-567 A degrees C/14-18 kbar) and blueschist facies (435-480 A degrees C/11-13 kbar) conditions have been recognized, respectively. Whereas the rest of the Massif underwent MP metamorphism under greenschist to amphibolite facies (525-555 A degrees C/6.5-7.5 kbar) conditions. Eclogite facies metamorphism in Sugozu nappe, which consists of homogeneous garnet-glaucophane-phengite schists with eclogite lenses is dated at 84.8 +/- A 0.8, 84.7 +/- A 1.5 and 82 +/- A 3 Ma (Santonian-Campanian) by Ar-40/Ar-39 phengite, U/Pb zircon and rutile dating methods, respectively. Similarly, phengites in GundogmuAY nappe representing an accretionary complex yield 82-80 Ma (Campanian) ages for blueschist facies metamorphism. During the exhumation, the retrograde overprint of the HP units under greenschist-amphibolite facies conditions and tectonic juxtaposition with the Barrovian units occurred during Campanian (75-78 Ma). Petrological and geochronological data clearly indicate a similar Late Cretaceous tectonometamorphic evolution for both Alanya (84-75 Ma) and Bitlis (84-72 Ma) Massifs. They form part of a single continental sliver (Alanya-Bitlis microcontinent), which was rifted from the southern part of the Anatolide-Tauride platform. The P-T-t coherence between two Massifs suggests that both Massifs have been derived from the closure of the same ocean (Alanya-Bitlis Ocean) located to the south of the Anatolide-Tauride block by a northward subduction. The boundary separating the autochthonous Tauride platform to the north from both the Alanya and Bitlis Massifs to the south represents a suture zone, the Pamphylian-Alanya-Bitlis suture. KW - Tauride KW - Eclogite KW - Alanya KW - Blueschist KW - Metamorphism Y1 - 2016 U6 - https://doi.org/10.1007/s00531-014-1092-8 SN - 1437-3254 SN - 1437-3262 VL - 105 SP - 247 EP - 281 PB - Springer CY - New York ER - TY - JOUR A1 - Scheffler, Franziska A1 - Oberhänsli, Roland A1 - Pourteau, Amaury A1 - Immenhauser, A. A1 - Candan, O. T1 - Sedimentologic to metamorphic processes recorded in the high-pressure/low-temperature Mesozoic Rosetta Marble of Anatolia JF - International journal of earth sciences N2 - Anatolia’s high-pressure metamorphic belts are characterized in part by a Neotethyan stratigraphic succession that includes a mid-Cretaceous hemi-pelagic marble sequence. This unit contains, towards its stratigraphic top, dm-to-m-long radiating calcitic rods forming rosette-like textures. Here, we refer to these features as “Rosetta Marble”. The remarkable textural similarity of non-metamorphic selenite crystals and radiating calcite rods in the Rosetta Marble strongly suggests that these textures represent pseudomorphs after selenites. Metamorphosed hemi-pelagic limestones, dominated by Rosetta selenite pseudomorphs, are alternating with siliceous meta-sediments containing relictic radiolaria tests. This stratigraphic pattern is indicative of transient phases characterized by evaporites precipitated from basinal brines alternating with non-evaporative hemi-pelagic deposition from normal-marine seawater. The regional distribution of Rosetta Marble exposures over 600 km is indicative of basin-scale evaporitic intervals. High-pressure, low-temperature metamorphism of these rocks is witnessed by Sr-rich (up to 3500 ppm), fibrous calcite pseudomorphs after aragonite and isolated aragonite inclusions in quartz. Peak metamorphic conditions of 1.2 GPa and 300–350 °C are attested by high-Si white mica thermobarometry. The Rosetta Marble case example examines the potential to unravel the complete history from deposition to diagenesis and metamorphism of meta-sedimentary rocks. KW - Gypsum KW - High-pressure metamorphism KW - Neotethys KW - Anatolia Y1 - 2016 U6 - https://doi.org/10.1007/s00531-015-1214-y SN - 1437-3254 SN - 1437-3262 VL - 105 SP - 225 EP - 246 PB - Springer CY - New York ER - TY - JOUR A1 - Oberhänsli, Roland A1 - Partzsch, Julius A1 - Candan, O. A1 - Cetinkaplan, Mete T1 - First occurrence of Fe-Mg-carpholite documenting a high pressure metamorphism in the metasediments of the Lycian nappes, SW Turkey Y1 - 2000 ER - TY - JOUR A1 - Pourteau, Amaury A1 - Sudo, Masafumi A1 - Candan, Osman A1 - Lanari, P. A1 - Vidal, O. A1 - Oberhänsli, Roland T1 - Neotethys closure history of Anatolia - insights from Ar-40-Ar-39 geochronology and P-T estimation in high-pressure metasedimentary rocks JF - Journal of metamorphic geology N2 - The multiple high-pressure (HP), low-temperature (LT) metamorphic units of Western and Central Anatolia offer a great opportunity to investigate the subduction-and continental accretion-related evolution of the eastern limb of the long-lived Aegean subduction system. Recent reports of the HP-LT index mineral Fe-Mg-carpholite in three metasedimentary units of the Gondwana-derived Anatolide-Tauride continental block (namely the Afyon Zone, the Oren Unit and the southern Menderes Massif) suggest a more complicated scenario than the single-continental accretion model generally put forward in previous studies. This study presents the first isotopic dates (white mica Ar-40-Ar-39 geochronology), and where possible are combined with P-T estimates (chlorite thermometry, phengite barometry, multi-equilibrium thermobarometry), on carpholite-bearing rocks from these three HP-LT metasedimentary units. It is shown that, in the Afyon Zone, carpholite-bearing assemblages were retrogressed through greenschist-facies conditions at c. 67-62 Ma. Early retrograde stages in the Oren Unit are dated to 63-59 Ma. In the Kurudere-Nebiler Unit (HP Mesozoic cover of the southern Menderes Massif), HP retrograde stages are dated to c. 45 Ma, and post-collisional cooling to c. 26 Ma. These new results support that the Oren Unit represents the westernmost continuation of the Afyon Zone, whereas the Kurudere-Nebiler Unit correlates with the Cycladic Blueschist Unit of the Aegean Domain. In Western Anatolia, three successive HP-LT metamorphic belts thus formed: the northernmost Tavsanli Zone (c. 88-82 Ma), the Oren-Afyon Zone (between 70 and 65 Ma), and the Kurudere-Nebiler Unit (c. 52-45 Ma). The southward younging trend of the HP-LT metamorphism from the upper and internal to the deeper and more external structural units, as in the Aegean Domain, points to the persistence of subduction in Western Anatolia between 93-90 and c. 35 Ma. After the accretion of the Menderes-Tauride terrane, in Eocene times, subduction stopped, leading to continental collision and associated Barrovian-type metamorphism. Because, by contrast, the Aegean subduction did remain active due to slab roll-back and trench migration, the eastern limb (below Southwestern Anatolia) of the Hellenic slab was dramatically curved and consequently teared. It therefore is suggested that the possibility for subduction to continue after the accretion of buoyant (e.g. continental) terranes probably depends much on palaeogeography. KW - Ar-40-Ar-39 geochronology KW - Anatolia KW - chlorite-phengite thermobarometry KW - high-pressure metasedimentary rocks Y1 - 2013 U6 - https://doi.org/10.1111/jmg.12034 SN - 0263-4929 SN - 1525-1314 VL - 31 IS - 6 SP - 585 EP - 606 PB - Wiley-Blackwell CY - Hoboken ER -