Transition from arc‐ to post‐collision extensional setting revealed by K–Ar dating and petrology: an example from the granitoids of the Eastern Pontide Igneous Terrane, Araklı‐Trabzon, NE Turkey

摘要: The Eastern Pontide Igneous Terrane (EPIT) includes several Cretaceous to Neogene intrusive rocks, ranging in composition from low-K tholeiitic gabbros through calc-alkaline and high-K metaluminous granitoids or peraluminous leucogranites alkaline syenites. Such high diversity age is also accompanied by a broad spectrum terms of geodynamics—i.e. arc syn-collisional thickening post-collisional extensional regimes. Shallow-seated porphyritic acidic intermediate rocks are oldest youngest, on the basis field relations, Gundogdu altered microgranite, Bogali K-feldspar-megacrystic monzogranite Uzuntarla granodiorite. These exposed southern part Arakli region, east Trabzon, Turkey, were studied their mineralogy petrography, whole-rock geochemistry hornblende K–Ar dating. mineralogical geochemical data reveal an apparent incompatible-element enrichment depletion, for unit unit, respectively. units yield ages 75.7 ± 1.55 61.4 ± 1.47 Ma 42.4 ± 0.87 41.2 ± 0.89 Ma, both mineralogy–geochemistry suggests that parts Eocene post-collision extensional-related igneous activity, respectively, EPIT northern Turkey. Copyright © 2005 John Wiley & Sons, Ltd.