OICC Press Iranian Journal of Earth Sciences 2228-785X 18 3 2026 09 30 Application of Ti-in-quartz and Zr-in-rutile Thermometers to Constrain Pressure-Temperature in Meta-ophiolitic Rocks of the Kazdağ Massif, NW Anatolia 10.57647/j.ijes.2025.16951 EN Firat Şengün Department of Mining and Mineral Extraction, Çan Vocational College, Çanakkale Onsekiz Mart University, Çan-Çanakkale, Turkey Journal Article 2026 09 30 Ophiolitic metagabbros are exposed in the Kazdağ Massif located in the northwestern part of Anatolia. Trace element compositions in rutile and quartz were determined for metagabbros from the Kazdağ Massif by LA-ICP-MS. Ti-in-quartz can be used as a thermobarometer in combination with the Zr-in-rutile thermometer. P-T conditions for ophiolitic metagabbros were calculated from the Ti content of quartz and Zr content of rutile, which are in equilibrium with each other. Ti contents of quartz ranged between 28 and 42 µg/g (average 36 µg/g). A P–T estimate can be obtained from the intersection of the Ti-in-quartz isopleths with the Zr-in-rutile isopleths, which yield ~ 660 ℃ and 1 GPa under amphibolite-facies conditions. The P-T conditions of meta-ophiolitic rocks suggest that they formed as a separate higher-pressure tectonic slice in the Kazdağ Massif. Amphibolite-facies metamorphism resulted from northward subduction of the İzmir-Ankara branch of the Neo-Tethyan Ocean under the Sakarya Zone. Metamorphism was followed by internal imbrication of the Kazdağ Massif, resulting from southerly directed compression during internal collision. Later, the Sakarya Zone collided with the Anatolide-Tauride Block located in the south. This collision and internal imbrication of the Kazdağ Massif caused thickness in the crust.