Akademik Veri Yönetim Sistemi
GEOSCIENCES JOURNAL, cilt.1, sa.1, ss.1-18, 2023 (SCI-Expanded)
LA-ICP-MS zircon geochronology and geochemistry (whole-rock & mineral 27 chemistry) from the Misis-Andırın Complex (MAC) volcanic rocks are reported. The MAC 28 records magmatic, sedimentary, and tectonic processes operating at the northern active margin 29 of the Neotethys (South Tethys) in the eastern Mediterranean district. The MAC represents an 30 association of an originally active continental margin including the Engizek (in the NE), 31 Andırın (central) and Misis (in the SW) segments. The felsic extrusives are depleted in HFSE 32 (high-field-strength elements), enriched in LILE (large-ion lithophile elements) and have flat33 type REE patterns; these trends and also biotite chemistry verify their supra-subduction zone 34 tectonic environment. The studied volcanic unit consists of mainly rhyolite, dacite and rare 35 andesite rocks, and is intercalated with Bulgurkaya Formation. These felsic extrusive rocks 36 show relative depletions in Ti + Nb, and partial enrichment in Cs, Rb, Ba, and Th in the N37 MORB (normal-mid ocean ridge basalt) normalised spider plot, suggesting their derivation 38 from a supra-subduction geodynamic environment. The La/Nb (1.92–2.33) and Nb/Th (1.0– 39 1.12) ratios of all the analysed extrusives from Andırın region present arc magmas or volcanic 40 rocks affinity that could have been contributed by crustal source contents and also examined 41 volcanics yield nearly flat Ba/La ratios with relatively increasing Th/Yb, suggesting the 42 contribution of sediments or crustal contamination. The Al-in-hornblende thermobarometry 43 (2.04 to 1.55 kbar) of Mg-Fe hornblende in the volcanics of the MAC represents their 44 crystallization of amphibole in the moderate to shallow crustal level at a maximum 6.7 km to 45 a minimum 5.1 km depth. The ilmenite-magnetite thermometer based on Fe-Ti oxide 46 equilibria shows that the Andırın region felsic magmas were at 717 °C and at an ƒO2 of 47 approximately 2.16 log units (+1.51 NNO). The MAC extrusive volcanic rocks were 48 produced throughout the Eocene period, and our new U-Pb zircon dating (47.13 ±0.5 Ma) 49 confirmed mainly younger Lutetian age of the volcanic activity in the Andırın area