ABSTRACT The Bursa mineral district in northwest Anatolia (Turkey) is an emerging prospective area for porphyry Cu-Mo (Au-Re) mineralization along the Western Tethyan Eocene magmatic belt that links the Balkan to Lesser Caucasus regions along the southern Black Sea coast. Field observations as well as time constraints on mineralized magmas of the Bursa district are limited. Additionally, the tectonic setting of Eocene magmatism in northwest Turkey is controversial and includes either Neotethyan slab roll-back or break-off scenario. We show that the Bursa mineral district consists of porphyry Cu-Mo, skarn Cu, and rare epithermal Au-Ag deposits, prospects, and occurrences on the footwall of the Eskişehir fault, south of the İzmir-Ankara-Erzincan suture zone. The porphyry prospects are hosted within porphyritic dioritic, granodioritic, and granitic rocks that were altered by potassic and phyllic assemblages and quartz-sulfide vein stockwork zones. Our new CA-TIMS and LA-ICP-MS U-Pb and 40 Ar/ 39 Ar ages indicate that porphyry mineralization of the Bursa district formed between 51 and 46 Ma and thus before the porphyry and epithermal Cu-Au mineralization of the Biga (~43–39 Ma) and Rhodope districts (~35–31 Ma) and the Serbo-Macedonian belt (~36–22 Ma). Therefore, we interpret that Eocene magmatism and associated Cu-Au-Mo mineralization migrated westward along the western part of the Western Tethyan Eocene magmatic belt. This migration, which is specific to the Eocene period, represents a second-order and diachronous response to the first-order southward magmatic front migration and roll-back initiation of the Hellenic slab beneath the Balkan-Aegean-western Anatolian region since the Late Cretaceous.

Abstract The Brucejack intermediate-sulfidation epithermal Au-Ag deposit, located 65 km north of Stewart, BC, forms part of a well-mineralized, structurally controlled, north-south gossanous trend associated with Early Jurassic intrusions straddling the Late Triassic-Early Jurassic Stuhini-Hazelton Group unconformity in the Sulphurets mineral district. Mining of the deposit commenced in mid-2017 after a long history of exploration dating back to the 1880s. Mineralization is hosted in deformed Lower Jurassic island-arc volcanic rocks of the Hazelton Group exposed on the eastern limb of the Cretaceous McTagg anticlinorium. High-grade Au-Ag mineralization was formed from ~184 to 183 Ma in association with a telescoped, multipulsed magmatic-hydrothermal system beneath an active local volcanic center. Precious metal mineralization occurs as coarse aggregates of electrum and silver sulfosalts in steeply dipping, E- to SE-trending quartz-carbonate vein stockwork zones cutting low-grade intrusion-related phyllic alteration. Epithermal vein development is interpreted to have occurred during the waning stages of Early Jurassic sinistral transpression in a compressive arc environment, followed by a limited Cretaceous deformation overprint.