Magmatism is a critical component in sustaining hydrothermal convection and metal transport during the formation of volcanogenic massive sulfide (VMS) deposits. Previous studies of magmatic petrogenesis in VMS systems have demonstrated that ore-related volcanic rocks have distinct whole-rock geochemical and isotopic signatures (i.e., high HFSE, REE, Th, εHf-Nd, zircon saturation T) relative to barren volcanic rocks, which supports models of elevated crustal heat flow during periods of ore deposition; however, the petrologic characteristics and intrinsic parameters (e.g., T, fO₂) related to these magmatic events in VMS districts remain poorly understood. Arc–back-arc assemblages from the mid-Paleozoic Yukon-Tanana terrane are well-characterized and include the Finlayson Lake VMS district, which is host to several felsic-hosted deposits (e.g., Kudz Ze Kayah, GP4F, Wolverine) that were generated in a peri-Laurentian continental back-arc tectonic setting. In this study, zircon from back-arc and coeval arc rocks in the Yukon-Tanana terrane was used as a proxy for primary magma formation conditions that generated VMS-proximal and VMS-distal stratigraphy. Our results indicate that zircon grains in VMS-proximal environments have unique textural, geochemical, and isotopic characteristics (e.g., low-aspect ratios, greater abundance of zircon-phosphate intergrowths, Th/U > 1, Zr/Hf > 80, T_zrc > 780 °C, εHf_i > –7) that are clearly distinguished from zircon in VMS-distal rocks in both the back-arc and arc settings (Th/U < 1, Zr/Hf < 80, T_zrc < 780 °C, εHf_i < –7). These signatures correlate to VMS-proximal magmas that were hotter, less fractionated, and contained greater juvenile melt contributions compared to VMS-distal magmas and reflect a series of high-flux magmatic events that directly correspond to the early tectonic development of Yukon-Tanana terrane. Moreover, this study underscores the importance of mineral-scale petrology, geochemistry, and geochronology in defining the primary magmatic conditions that generated VMS-related felsic rocks and highlights the utility of zircon as a prospectivity tool in both grassroots and brownfields VMS exploration.

岩浆作用是火山成因块状硫化物（VMS）矿床形成过程中维持热液对流和金属迁移的关键组成部分。先前对VMS系统中岩浆成因的研究表明，与矿有关的火山岩相对于贫瘠火山岩具有明显的全岩地球化学和同位素特征（即高HFSE、REE、Th、εHf-Nd、锆石饱和度T），这支持矿石沉积期间地壳热流升高的模型；然而，岩石学特征和内在参数（例如，T、f O ₂）与 VMS 地区这些岩浆事件有关的信息仍然知之甚少。中古生代育空-塔纳纳地体的弧-弧后组合具有良好的特征，其中包括 Finlayson Lake VMS 区，该区是多个长英质矿床（例如 Kudz Ze Kayah、GP4F、Wolverine）的所在地。位于近劳伦特大陆弧后构造环境中。在这项研究中，来自育空-塔纳纳地体弧后和同时代弧岩的锆石被用作原始岩浆形成条件的代表，产生了 VMS 近端和 VMS 远端地层。我们的结果表明，VMS 近端环境中的锆石颗粒具有独特的结构、地球化学和同位素特征（例如，低纵横比、锆石-磷酸盐共生体丰度较高、Th/U > 1、Zr/Hf > 80、T _zrc > 780 °C, εHf _i  > –7) 与弧后和弧环境下 VMS 远端岩石中的锆石有明显区别 (Th/U < 1, Zr/Hf < 80, T zrc < 780 _°  C , εHf _i < –7)。这些特征与 VMS 近端岩浆相关，与 VMS 远端岩浆相比，VMS 近端岩浆温度更高、分馏更少，并且含有更大的新生熔融贡献，并反映了一系列高通量岩浆事件，这些事件直接对应于育空-塔纳纳地体的早期构造发展。此外，这项研究强调了矿物尺度岩石学、地球化学和地质年代学在定义生成与 VMS 相关的长英质岩石的主要岩浆条件方面的重要性，并强调了锆石作为基层和棕地 VMS 勘探中的前景工具的实用性。