Zircon Petrochronology of the Kışladaǧ Porphyry Au Deposit (Turkey)

Article Article scientifique Article Zircon Petrochronology of the Kışladaǧ Porphyry Au Deposit (Turkey) eng 2021 author Paolillo Luca 774825 author Chiaradia Massimo 0000-0003-4943-2480 110575 author Ulianov Alexey 10.5382/econgeo.4864 0361-0128 Porphyry deposits typically occur in subduction-related arcs but have more recently also been described in postsubduction, collisional to extensional back-arc settings. These different tectonic environments not only might imply different genetic processes but also seem to result in different metal endowments (e.g., Au rich versus Cu rich). It is therefore relevant, also for exploration purposes, to understand the magmatic processes involved in porphyry formation in these different tectonic environments. This study focuses on the Kışladaǧ porphyry Au (17.4 Moz) deposit in western Anatolia, which is centered on a series of porphyritic monzonite stocks of high-K calc-alkaline to shoshonitic affinity and formed in a continental rifting environment. With 17.4 Moz of Au, Kışladaǧ is of global metallogenic importance and hence a good example for studying the genetic processes associated with porphyry deposits in extensional back-arc settings. We herein combine a comprehensive set of new zircon textural observations, in situ zircon trace element and Hf isotope data, and previously published zircon geochronology to study the magmatic processes associated with porphyry deposit formation at Kışladaǧ. We show that mafic rejuvenation of a slowly crystallizing (between ~15.8 and 14.9 Ma) magma reservoir below Kışladaǧ immediately preceded porphyry deposit formation. Zircon trace elements and geochronology suggest a longer and deeper evolution for the early fertile magmas compared to the later infertile magmas. Magma evolution at Kışladaǧ was accompanied by crustal wall-rock assimilation. Whole-rock Nd and Sr radiogenic isotopes show that increasing asthenosphere-derived melt input under accelerated regional extension caused a loss in fertility of the system over time. Dewey 550 42 Département des sciences de la Terre 154 false 663 Isotope Geochemistry, Geochronology and Thermochronology 692 Mineral Resources and Geofluids Economic Geology 8e2469e2-ea90-4a58-9429-0b453bec8db4 Article (Published version) Restricted Paolillo_EconGeol_2021.pdf 9503647 application/pdf restrictedAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre

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Zircon Petrochronology of the Kışladaǧ Porphyry Au Deposit (Turkey)	Economic Geology			2021	319	3

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Paolillo, Luca