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.

中文翻译：

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Kışladaǧ Porphyry Au 矿床的锆石岩石年代学（土耳其）

斑岩沉积物通常发生在与俯冲相关的弧中，但最近也被描述在俯冲后、碰撞到伸展的弧后环境中。这些不同的构造环境不仅可能意味着不同的遗传过程，而且似乎也导致了不同的金属禀赋（例如，富金与富铜）。因此，了解这些不同构造环境中斑岩形成所涉及的岩浆过程也与勘探目的相关。本研究的重点是位于安纳托利亚西部的 Kışladaǧ 斑岩 Au (17.4 Moz) 矿床，该矿床以一系列高钾钙碱性与钾玄武岩亲和性的斑状二长岩储量为中心，形成于大陆裂谷环境中。含 17.4 Moz 的 Au，Kışladaǧ 具有全球成矿重要性，因此是研究与弧后伸展环境中斑岩矿床相关的成因过程的一个很好的例子。我们在此结合了一套全面的新锆石结构观测、原位锆石微量元素和 Hf 同位素数据，以及之前发表的锆石地质年代学研究与 Kışladaǧ 斑岩矿床形成相关的岩浆过程。我们表明，在 Kışladaǧ 下方缓慢结晶（约 15.8 至 14.9 Ma）岩浆储层的基性复兴紧接在斑岩矿床形成之前。锆石微量元素和地质年代学表明，与晚期不育岩浆相比，早期肥沃岩浆的演化时间更长、更深。Kışladaǧ 的岩浆演化伴随着地壳围岩同化。