Early-Middle Jurassic metamorphic and non-metamorphic supra-subduction zone ophiolite fragments in a Late Cretaceous ophiolitic melange (northern Turkey): implications for long-lived and supra-subduction zone ophiolite formation


Ozkan M., ÇELİK Ö. F. , Cortuk R. M. , Topuz G., Zack T., Cubukcu E.

INTERNATIONAL JOURNAL OF EARTH SCIENCES, 2022 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1007/s00531-022-02235-9
  • Journal Name: INTERNATIONAL JOURNAL OF EARTH SCIENCES
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Geobase, INSPEC, Pollution Abstracts
  • Keywords: Jurassic, Metamorphic sole rocks, Ophiolites, Subduction erosion, Tethyan, ERZINCAN SUTURE ZONE, TAURIDE BELT OPHIOLITES, SLAB BREAK-OFF, CENTRAL ANATOLIA, U-PB, OCEANIC LITHOSPHERE, TECTONIC EVOLUTION, EASTERN PONTIDES, SOLE ROCKS, ACCRETIONARY COMPLEX

Abstract

The Late Cretaceous accretionary complexes along the Izmir-Ankara-Erzincan (IAE) Neo-Tethyan suture zone in northern Turkey record the subduction-accretion processes of the oceanic lithosphere ranging in age from the Late Triassic to the Late Cretaceous. These accretionary complexes contain fragments of Early and Middle Jurassic metamorphic and non-metamorphic ophiolites. Here, we report new geochemical and geochronological data from the metamorphic and non-metamorphic ophiolitic rocks, which are observed in the Tekelidag melange (northern Sivas) of the IAE suture zone. Geochemical characteristics of these rocks point to formation in a subduction-related tectonic setting. Igneous zircons from meta-plagiogranite injected into the meta-ophiolitic rocks yielded zircon U-Pb age of 188 +/- 4 Ma (2 sigma, Early Jurassic), and those from a non-metamorphic plagiogranite crosscutting the non-metamorphic ophiolitic rocks gave an age value of 168 +/- 2 Ma (2 sigma, Middle Jurassic). The igneous crystallization age of the non-metamorphic plagiogranite is identical with the metamorphic age of meta-ophiolitic rocks, which has been dated as Middle Jurassic (166.7 +/- 2 Ma, 2 sigma) by the Ar-40-Ar-39 method. These age data indicate that (i) the supra-subduction zone ophiolite formation lasted about 20 Ma, (ii) the supra-subduction zone ophiolite and the meta-ophiolitic rocks formed simultaneously in the Middle Jurassic, and (iii) the meta-ophiolitic rocks are remnants of the metamorphosed equivalents of the Early Jurassic supra-subduction zone oceanic crust. The supra-subduction zone ophiolite formation probably occurred over an extended period of time in the Jurassic Neo-Tethys.