The origin and P-T conditions of the metamorphic sole rocks beneath the Late Cretaceous Pinarbasi Ophiolite, Eastern-Central Anatolia


Cortuk R. M., ÇELİK Ö. F., Ozkan M., Marzoli A., Alkan A.

INTERNATIONAL GEOLOGY REVIEW, vol.65, no.2, pp.296-316, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 65 Issue: 2
  • Publication Date: 2023
  • Doi Number: 10.1080/00206814.2022.2045638
  • Journal Name: INTERNATIONAL GEOLOGY REVIEW
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC, Pollution Abstracts
  • Page Numbers: pp.296-316
  • Keywords: Ophiolite, metamorphic sole rocks, P-T conditions, pseudosection modelling, subduction zone, POZANTI-KARSANTI OPHIOLITE, TAURIDE BELT OPHIOLITES, ERZINCAN SUTURE ZONE, SEMAIL OPHIOLITE, WHOLE-ROCK, MERSIN OPHIOLITE, OMAN OPHIOLITE, SW TURKEY, U-PB, NEOTETHYAN OPHIOLITE
  • Kocaeli University Affiliated: Yes

Abstract

Metamorphic sole rocks of the Pinarbasi Ophiolite are one of the best-preserved rock units observed along the Tauride Ophiolite Belt in Turkey. The metamorphic sole rocks observed as tectonic slices at the base of mantle tectonites as well as blocks in the melange units consist mainly of garnet-clinopyroxene-amphibolite, garnet-amphibolite, amphibolite, epidote-amphibolite, quartz-amphiboleschist and metabasalt. The amphibolites display a wide range of geochemical signatures such as those of N-MORB, E-MORB, OIB and IAT. The metabasalts exhibit OIB geochemical characteristics. P-T estimates indicate that the garnet-clinopyroxene-amphibolites reached peak metamorphic conditions of 790-840 degrees C and 12-14 kbar. High-grade metamorphism is followed by a stage of decompression, which is indicated by the presence of symplectitic growth of amphibole and plagioclase over garnet in garnet-clinopyroxene-amphibolites. P-T estimates for garnet-clinopyroxene-amphibolites suggest that they were metamorphosed under granulite-facies conditions (ca. 35-40 km). High temperature estimated from granulite facies rocks should be ascribed to the occurrence of the sole rocks during the inception of the intra-oceanic subduction, beneath young or relatively hot oceanic lithosphere. On the other hand, mineral paragenesis of the metabasalts suggest greenschist facies metamorphic conditions. Protoliths of the metabasalts were probably metamorphosed during final stages of subduction where they were very close to sea floor as the subduction zone was probably clogged by a seamount. The greenschist- and granulite-facies sole rocks were metamorphosed probably beneath the hot oceanic lithosphere at different depths of the subduction zone. Considering all these data are important to better understanding intra-oceanic subduction and final obduction events of the Tethys Ocean.