U-Pb zircon geochronology and geochemistry of the metamorphic sole rocks of the Meydan melange, South-East Turkey: Implications for ophiolite emplacement and protolith

Creative Commons License

NURLU N.

GEOLOGICA CARPATHICA, cilt.71, sa.2, ss.183-209, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 71 Sayı: 2
  • Basım Tarihi: 2020
  • Doi Numarası: 10.31577/geolcarp.71.2.6
  • Dergi Adı: GEOLOGICA CARPATHICA
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, BIOSIS, Geobase, Directory of Open Access Journals
  • Sayfa Sayıları: ss.183-209
  • Anahtar Kelimeler: Metamorphic sole, South-East Anatolia, U-Pb geochronology, zircon, SUBDUCTION-ZONE METAMORPHISM, POZANTI-KARSANTI OPHIOLITE, KIZILDAG HATAY OPHIOLITE, RARE-EARTH-ELEMENTS, WHOLE-ROCK, TECTONIC ENVIRONMENT, MERSIN OPHIOLITE, CENTRAL ANATOLIA, ALPINE PERIDOTITES, TAURIDE OPHIOLITES
  • Çukurova Üniversitesi Adresli: Evet

Özet

Metamorphic sole rocks at the base of the mantle tectonites of the Meydan ophiolite in South-East Anatolia, Turkey, are directly overlain by sheared serpentinites and cut by unmetamorphosed mafic dikes. They are found in areas close to the forefront of the Tauride thrust and are described as biotite amphibole schist (Bt+ Hbl + Act+ Plg+ Rt +/- Zrn), prehnite-ptimpcilyite amphibole schist (Prh Pmp+ Act + Plg +/- Rt +/- Ttn), amphibole schist (Fe2+-Act -Qtz+ Plg +/- Anl +/- Zrn), and amphibolite (Mg-Hbl-Plg-+/- Zrn +/- Rt). They are identified as island arc tholeiites (IATs) based on their major- and trace-element whole-rock chemistry and mineral composition. The mafic dikes intruding into the metamorphic sole rocks and mantle tectonites exhibit tholeiitic affinity (Nb/Y =0.03-0.13) and are geochemically similar to island-arc basalts. The multiple elements, rare earth element (REE) trends, and related diagrams suggest that the mafic dikes were generated in a supra-subduction zone (SSZ) setting. Geothermobarometric examination based on the chemical compositions of the magnesio-hornblende in the amphibolites indicated that the pressure and temperature during the metamorphism were similar to 2.4 kbar (at depths of roughly 9 km) and similar to 630 degrees C, respectively. To elucidate the relationship and timing between the formation of the Meydan ophiolite and that of the metamorphic sole rocks, this paper presents new zircon U-Pb geochronological data from two samples of sole rocks, the ages of which are indicated to lie in the range of 81.4 +/- 0.69 Ma to 85.4 0.93 Ma (Santonian-Campanian). The precise U-Pb geochronology and the detailed petrographical and geochemical features of the metamorphic sole rocks and the protolith are evaluated to identify the tectonic environments of supra-subduction realms characterizing the South-Eastern Anatolian Orogenic Belt (SiOB). The metamorphic sole rocks were formed as a result of intra-oceanic thrusting during supra-subduction events in the basin throughout the closure of the SAOB in the Late Cretaceous.