Akademik Veri Yönetim Sistemi
9th Geochemistry Symposium with International Participation, Aydın, Türkiye, 17 - 21 Ekim 2022, cilt.1, ss.1
Metamorphic sole rocks at the base of the mantle
tectonites of the Meydan ophiolite are directly overlain by sheared
serpentinites and cut by un-metamorphosed mafic dikes. Metamorphic sole rocks
are described as biotite amphibole schist (Bt+Hbl+Act+Plg+Rt±Zrn),
prehnite-pumpellyite-amphibole schist (Prh+Pmp+Act+Plg±Rt±Ttn), amphibole
schist (Fe2-Act+Qtz+Plg±Anl±Zrn), and amphibolite (Mg-Hbl+Plg±Zrn±Rt). These
rocks are identified as island arc tholeiites because of their major- and
trace-element whole-rock chemistry and mineral composition. The mafic dikes
intruding into the metamorphic sole rocks and mantle tectonites show tholeiitic
affinity (Nb/Y = 0.03–0.13) and are geochemically similar to island-arc
basalts. The multi-element, rare earth element trends and related diagrams
suggest that the mafic dikes are generated in a supra-subduction setting. Geothermobarometric
examinations based on chemical compositions of magnesio-hornblende in the
amphibolites suggest that the pressure the pressure was approximately 2.4 kbar
(at depths of roughly 9 km) and the temperature during metamorphism was
approximately 630 ̊C. To help understand 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
metamorphic sole rocks give ages between 81.4 ± 0.69 Ma and 85.4 ± 0.93 Ma
(Santonian–Campanian). It is herein proposed that the geochemical,
geochronological, petrological, and field evidence show that the Meydan
ophiolite and mafic dikes occurred in a supra-subduction environment and that
the metamorphic sole rocks were formed as a result of intra-oceanic thrusting
during supra-subduction events in the basin throughout the closing of the
South-eastern Anatolian Orogenic Belt (SAOB) in the Late Cretaceous.