Low-sulfidation epithermal mineralization in a post-subduction setting: Insights from the Eocene Gicik Au-Ag ± Te deposit, North-Central Anatolia (Turkiye)
ORE GEOLOGY REVIEWS, vol.194, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 194
- Publication Date: 2026
- Doi Number: 10.1016/j.oregeorev.2026.107345
- Journal Name: ORE GEOLOGY REVIEWS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, Geobase, Directory of Open Access Journals, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Open Archive Collection: AVESIS Open Access Collection
- Middle East Technical University Affiliated: Yes
Abstract
The Turkish segment of the Western Tethyan Metallogenic Belt hosts numerous epithermal deposits; however, parts of north-central Anatolia remain underexplored, limiting understanding of mineralization styles and tectonomagmatic controls in this sector. The Gicik Au-Ag +/- Te deposit, located along the southern Pontide margin, provides an opportunity to address this gap. This study aims to characterize the geology, mineralization styles, and timing of the Gicik epithermal system, and to constrain its relationship with regional tectonomagmatic evolution through field observations combined with mineralogical, geochemical, and geochronological analyses. Mineralized veins are hosted by a volcanic-volcaniclastic sequence composed of medium-K calc-alkaline dacitic agglomerates and lavas displaying arc-like geochemical signatures. Low-sulfidation-style epithermal Au-Ag +/- Te mineralization occurs along sub-vertical veins emplaced within NNE-trending oblique-slip faults. A core of silicification passes first into vein-proximal argillic alteration and then into a broader zone of propylitic alteration. Veins display superimposed textures including stockwork and lattice-bladed veins as well as multi-stage colloform banding and hydrothermal brecciation. Two distinct stages of mineralization were identified in association with these textures. Early stage is comprised by pyrite-arsenopyrite-marcasite with refractory gold primarily occurring in colloformbanded, massive silica, and lattice-bladed veins. Main Au-Ag-Te mineralization occurs in late breccia veins consisting of pyrite, Ag-tetrahedrite, native Au, tellurides, and rare selenides. Overlapping ages of volcanic hosts and hydrothermal illite suggest that the Gicik epithermal system was spatio-temporally associated with middle Eocene (similar to 44.5 Ma) magmatism that post-dated Pontide-Anatolide-Tauride collision. Formation of low-sulfidation epithermal mineralization was controlled by NNE-trending, transpressional structures developed during the advanced stages of collision.