Thermal structure of low-grade accreted Lower Cretaceous distal turbidites, the Central Pontides, Turkey: insights for tectonic thickening of an accretionary wedge

Albian-Turonian subduction-accretionary complexes are exposed widely in the Central Pontides. A major portion of the accretionary complexes is made up of a metaflysch sequence consisting of slate/phyllite and metasandstone intercalation with blocks of marble, Na-amphibole bearing metabasite, and serpentinite. The metaflysch sequence represents distal parts of a large Lower Cretaceous submarine turbidite fan deposited on the Laurasian active continental margin that was subsequently accreted and metamorphosed during the Albian. Raman spectra of carbonaceous material of the metapelitic rocks revealed that the metaflysch consists of metamorphic packets with distinct peak metamorphic temperatures. The majority of the metapelites are low-temperature (ca. 330°C) slates characterized by lack of differentiation of the graphite (G) and D2 defect bands. They possibly represent offscraped distal turbidites along the toe of the Albian accretionary wedge. Other phyllites are characterized by a slightly pronounced G band with a D2 defect band occurring on its shoulder. Peak metamorphic temperatures of these phyllites are constrained to 370-385 °C. The phyllites are associated with a strip of incipient blueschist facies metabasites and are found as a sliver within the offscraped distal turbidites. We interpret the phyllites as underplated continental sediments together with oceanic crustal basalt along the basal décollement. Tectonic emplacement of the underplated rocks into the offscraped distal turbidites was possibly achieved by out-of-sequence thrusting causing tectonic thickening and uplift of the wedge.

Thermal structure of low-grade accreted Lower Cretaceous distal turbidites, the Central Pontides, Turkey: insights for tectonic thickening of an accretionary wedge

Albian-Turonian subduction-accretionary complexes are exposed widely in the Central Pontides. A major portion of the accretionary complexes is made up of a metaflysch sequence consisting of slate/phyllite and metasandstone intercalation with blocks of marble, Na-amphibole bearing metabasite, and serpentinite. The metaflysch sequence represents distal parts of a large Lower Cretaceous submarine turbidite fan deposited on the Laurasian active continental margin that was subsequently accreted and metamorphosed during the Albian. Raman spectra of carbonaceous material of the metapelitic rocks revealed that the metaflysch consists of metamorphic packets with distinct peak metamorphic temperatures. The majority of the metapelites are low-temperature (ca. 330°C) slates characterized by lack of differentiation of the graphite (G) and D2 defect bands. They possibly represent offscraped distal turbidites along the toe of the Albian accretionary wedge. Other phyllites are characterized by a slightly pronounced G band with a D2 defect band occurring on its shoulder. Peak metamorphic temperatures of these phyllites are constrained to 370-385 °C. The phyllites are associated with a strip of incipient blueschist facies metabasites and are found as a sliver within the offscraped distal turbidites. We interpret the phyllites as underplated continental sediments together with oceanic crustal basalt along the basal décollement. Tectonic emplacement of the underplated rocks into the offscraped distal turbidites was possibly achieved by out-of-sequence thrusting causing tectonic thickening and uplift of the wedge.

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  • Altherr R, Topuz G, Marschall H, Zack T, Ludwig T (2004). Evolution of a tourmaline-bearing lawsonite eclogite from the Elekdag area (Central Pontides, N Turkey): evidence for infiltration of slab-derived B-rich fluids during exhumation. Contrib Mineral Petr 148: 409–425.
  • Aoya M, Kouketsu Y, Endo S, Shimizu H, Mizukami T, Nakamura D, Wallis S (2010). Extending the applicability of the Raman carbonaceous-material geothermometer using data from contact metamorphic rocks. J Metamorph Geol 28: 895–914.
  • Aygül M, Okay AI, Oberhänsli R, Sudo M (2015a). Pre-collisional accretionary growth of the southern Laurasian margin, Central Pontides, Turkey. Tectonophysics (submitted).
  • Aygül M, Okay AI, Oberhänsli R, Schmidt A, Sudo M (2015b). Late Cretaceous infant intra-oceanic arc volcanism, the Central Pontides, Turkey: petrogenetic and tectonic implications. J Asian Earth Sci (in press).
  • Barkurt MY, Bilginer E, Pehlivan Ş, Örçen S (1990). Geology of the Kastamonu-Ovacık Region. Ankara, Turkey: MTA Report No. 9079 (in Turkish).
  • Beyssac O, Bollinger L, Avouac JP, Goffe B (2004). Thermal metamorphism in the Lesser Himalaya of Nepal determined from Raman spectroscopy of carbonaceous material. Earth Planet Sci Lett 225: 233–241.
  • Beyssac O, Goffé B, Chopin C, Rouzaud JN (2002a). Raman spectra of carbonaceous material in metasediments: a new geothermometer. J Metamorph Geol 20: 859–871.
  • Beyssac O, Rouzaud JN, Goffé B, Brunet F, Chopin C (2002b). Characterization of high-pressure, low-temperature graphitization: a Raman microspectroscopy and HRTEM study. Contrib Mineral Petr 143: 19–31.
  • Beyssac O, Simoes M, Avouac JP, Farley KA, Chen YG, Chan YC, Goffe B (2007). Late Cenozoic metamorphic evolution and exhumation of Taiwan. Tectonics 26: TC6001.
  • Boztuğ D (1992). Daday-Devrekani Masifi güney kesiminin litostratigrafi birimleri ve tektoniği. MTA Dergisi 114: 1–20 (in Turkish).
  • Chen F, Siebel W, Satır M, Terzioğlu N, Saka K (2002). Geochronology of the Karadere basement (NW Turkey) and implications for the geological evolution of the İstanbul Zone. Int J Earth Sci 91: 469–481.
  • Dean WT, Monod O, Rickards RB, Demir O, Bultynck P (2000). Lower Palaeozoic stratigraphy and palaeontology, KaradereZirze area, Pontus Mountains, northern Turkey. Geol Mag 137: 555–582.
  • Diessel CFK, Brothers NR, Black PM (1978). Coalification and graphitization in high-pressure schists in New Caledonia. Contrib Mineral Petr 68: 63–78.
  • Görür N (1988). Timing of opening of the Black Sea basin. Tectonophysics 147: 247–262.
  • Hippolyte JC, Müller C, Kaymakçı N, Sangu E (2010). Dating of the Black Sea Basin: new nannoplankton ages from its inverted margin in the Central Pontides (Turkey). In: Sosson M, Kaymakci N, Stephenson RA, Bergerat F, Starostenko V, editors. Sedimentary Basin Tectonics from the Black Sea and Caucasus to the Arabian Platform. London, UK: Geological Society of London Special Publications, pp. 113–136.
  • Itaya T (1981). Carbonaceous material in pelitic schists of the Sanbagawa metamorphic belt in central Shikoku, Japan. Lithos 14: 215–224.
  • Karig DE, Sharman GF (1975). Subduction and accretion in trenches. Geol Soc Am Bull 86: 377–389.
  • Kimura G, Ludden J (1995). Peeling oceanic crust in subduction zones. Geology 23: 217–220.
  • Lahfid A, Beyssac O, Deville E, Negro F, Chopin C, Goffé B (2010). Evolution of the Raman spectrum of carbonaceous material in low-grade metasediments of the Glarus Alps (Switzerland). Terra Nova 22: 354–360.
  • Landis CA (1971). Graphitization of dispersed carbonaceous materials in metamorphic rocks. Contrib Mineral Petr 30: 34–45.
  • Marroni M, Frassi C, Göncüoglu MC, Di Vincenzo G, Pandolfi L, Rebay G, Ellero A, Ottria G (2014). Late Jurassic amphibolitefacies metamorphism in the Intra-Pontide Suture Zone (Turkey): an eastward extension of the Vardar Ocean from the Balkans into Anatolia? J Geol Soc London 171: 605–608.
  • McCall GJH (2002). A summary of the geology of the Iranian Makran. In: Clift PD, Kroon D, Gaedicke C, Craig J, editors. The Tectonic and Climatic Evolution of the Arabian Sea Region. London, UK: Geological Society of London Special Publications, pp. 147–204.
  • Meijers MJM, Vrouwe B, van Hinsbergen DJJ, Kuiper KF, Wijbrans J, Davies GR, Stephenson RA, Kaymakcı N, Matenco L, Saintot A (2010). Jurassic arc volcanism on Crimea (Ukraine): implications for the paleo-subduction zone configuration of the Black Sea region. Lithos 119: 412–426.
  • Moore GF, Taira A, Klaus A, Becker L, Boeckel B, Cragg BA, Dean A, Fergusson CL, Henry P, Hirano S et al. (2001). New insights into deformation and fluid flow processes in the Nankai Trough accretionary prism: results of Ocean Drilling Program Leg 190. Geochem Geophy Geosy 2: 1058.
  • Morley CK (1988). Out-of-sequence thrusts. Tectonics 7: 539–561. Nemanich RJ, Solin SA (1979). First- and second-order Raman scattering from finite-size crystals of graphite. Phys Rev B 20: 392–401.
  • Nikishin AM, Okay AI, Tüysüz O, Demirer A, Wannier M, Amelin N, Petrov E (2015). The Black Sea basins structure and history: new model based on new deep penetration regional seismic data. Part 2: tectonic history and paleogeography. Mar Petrol Geol 59: 656–670.
  • Nzegge OM, Satır M, Siebel W, Taubald H (2006). Geochemical and isotopic constraints on the genesis of the Late Palaeozoic Deliktas¸ and Sivrikaya granites from the Kastamonu granitoid belt (Central Pontides, Turkey). Neues Jb Miner Abh 183: 27– 40.
  • Ohmori K, Taira A, Tokuyama H, Sakaguchi A, Okamura M, Aihara A (1997). Paleothermal structure of the Shimanto accretionary prism, Shikoku, Japan: role of an out-of-sequence thrust. Geology 25: 327–330.
  • Okay AI, Altıner D, Kılıç AM (2015). Triassic limestone, turbidites and serpentinite–the Cimmeride orogeny in the Central Pontides. Geol Mag 152: 460–479.
  • Okay AI, Nikishin AM (2015). Tectonic evolution of the southern margin of Laurasia in the Black Sea region. Int Geol Rev 57: 1051–1076.
  • Okay AI, Şengör AMC, Görür N (1994). Kinematic history of the opening of the Black Sea and its effect on the surrounding regions. Geology 22: 267–270.
  • Okay AI, Sunal G, Sherlock S, Altıner D, Tüysüz O, Kylander-Clark ARC, Aygül M (2013). Early Cretaceous sedimentation and orogeny on the active margin of Eurasia: Southern Central Pontides, Turkey. Tectonics 32: 1247–1271.
  • Okay AI, Sunal G, Tüysüz O, Sherlock S, Keskin M, Kylander-Clark ARC (2014). Low-pressure–high-temperature metamorphism during extension in a Jurassic magmatic arc, Central Pontides, Turkey. J Metamorph Geol 32: 49–69.
  • Okay AI, Tüysüz O (1999). Tethyan sutures of northern Turkey. In: Durand B, Jolivet L, Horvath F, Seranne M, editors. The Mediterranean Basins: Tertiary Extension within the Alpine Orogen. London, UK: Geological Society of London Special Publications, pp. 475–515.
  • Okay AI, Tüysüz O, Satır M, Özkan-Altıner S, Altıner D, Sherlock S, Eren RH (2006). Cretaceous and Triassic subduction-accretion, HP/LT metamorphism and continental growth in the Central Pontides, Turkey. Geol Soc Am Bull 118: 1247–1269.
  • Pasteris JD (1989). In situ analysis in geological thin-sections by Laser Raman microprobe microspectroscopy: a cautionary note. Appl Spectrosc 43: 567–570.
  • Pasteris JD, Wopenka B (1991). Raman spectra of graphite as indicators of degree of metamorphism. Can Mineral 29: 1–9.
  • Platt JP (1986). Dynamics of orogenic wedges and the uplift of highpressure metamorphic rocks. Geol Soc Am Bull 97: 1037–1053.
  • Platt JP, Leggett JK, Young J, Raza H, Alam S (1985). Large scale sediment underplating in the Makran accretionary prism, southwest Pakistan. Geology 13: 507–511.
  • Rahl JM, Anderson KM, Brandon MT, Fassoulas C (2005). Raman spectroscopic carbonaceous material thermometry of lowgrade metamorphic rocks: calibration and application to tectonic exhumation in Crete, Greece. Earth Planet Sci Lett 240: 339–354.
  • Sadezky A, Muckenhuber H, Grothe H, Niessner R, Pöschl U (2005). Raman microspectroscopy of soot and related carbonaceous materials: spectral analysis and structural information. Carbon 43: 1731–1742.
  • Sample JC, Fisher DM (1986). Duplex accretion and underplating in an ancient accretionary complex, Kodiak Islands, Alaska. Geology 14: 160–163.
  • Scharf A, Handy MR, Ziemann MA, Schmid SM (2013). Peaktemperature patterns of polyphase metamorphism resulting from accretion, subduction and collision (eastern Tauern Window, European Alps) – a study with Raman microspectroscopy on carbonaceous material (RSCM). J Metamorph Geol 31: 863–880.
  • Tissot BP, Welte DH (1978). Petroleum Formation and Occurrence. A New Approach to Oil and Gas Exploration. 1st ed. Heidelberg, Germany: Springer-Verlag.
  • Topuz G, Göçmengil G, Rolland Y, Çelik ÖF, Zack T, Schmitt AK (2013). Jurassic accretionary complex and ophiolite from northeast Turkey: no evidence for the Cimmerian continental ribbon. Geology 41: 255–258.
  • Tuinstra F, Koenig JL (1970). Raman spectrum of graphite. J Chem Phys 53: 1126–1130.
  • Tüysüz O (1990). Tectonic evolution of a part of the Tethyside orogenic collage: the Kargı Massif, northern Turkey. Tectonics 9: 141–160.
  • Tüysüz O (1999). Geology of the Cretaceous sedimentary basins of the Western Pontides. Geol J 34: 75–93.
  • Tüysüz O, Tekin UK (2007). Timing of imbrication of an active continental margin facing the northern branch of Neotethys, Kargı Massif, northern Turkey. Cretaceous Res 28: 754–764.
  • Uğuz MF, Sevin M, Duru M (2002). Geological Map of Turkey. 1: 500.000 Scaled Sinop Sheet. Ankara, Turkey: MTA. Ustaömer T, Robertson AHF (1993). A Late Paleozoic-Early Mesozoic marginal basin along the active southern continental margin of Eurasia: evidence from the Central Pontides (Turkey) and adjacent regions. Geol J 28: 219–238.
  • Ustaömer T, Robertson AHF (1994). Late Paleozoic marginal basin and subduction-accretion: the Paleotethyan Küre Complex, Central Pontides, northern Turkey. J Geol Soc London 151: 291–305.
  • Ustaömer T, Robertson AHF (1997). Tectonic-sedimentary evolution of the North-Tethyan margin in the Central Pontides of northern Turkey. In: Robinson, AG, editor. Regional and Petroleum Geology of the Black Sea and Surrounding Region. Tulsa, OK, USA: AAPG, pp. 255–290.
  • Ustaömer T, Robertson AHF (1999). Geochemical evidence used to test alternative plate tectonic models for pre-Upper Jurassic (Palaeotethyan) units in the Central Pontides, N Turkey. Geol J 34: 25–53.
  • von Huene R, Scholl DW (1991). Observations at convergent margins concerning sediment subduction, subduction erosion, and the growth of continental crust. Rev Geophys 3: 279–316.
  • Yılmaz O, Boztuğ D (1986). Kastamonu granitoid belt of northern Turkey: first arc plutonism product related to the subduction of the Paleo-Tethys. Geology 14: 179–183.
  • Yui TF, Huang E, Xu J (1996). Raman spectrum of carbonaceous material: a possible metamorphic grade indicator for lowgrade metamorphic rocks. J Metamorph Geol 14: 115–124.
  • Wopenka B, Pasteris JD (1993). Structural characterization of kerogens to granulite-facies graphite: applicability of Raman microprobe spectroscopy. Am Mineral 78: 533–557.