Constraints on the genesis of Au veins in interior Alaska: Evidence from geochronology and vein textures

The origin of Au-bearing, low sulfide quartz veins in the Pogo and Tibbs Creek regions of interior Alaska remain enigmatic. Intrusion-related Au and mesozonal orogenic vein models have both been proposed (Thompson and Newberry, 2000; Rhys et al., 2003; Goldfarb et al., 2022; Dilworth et al., 2007). To date, studies of igneous geochronology and metamorphic timing have shown that gold veins formed between intervals of magmatism and post-date regional metamorphic fabrics. Relatively little description of detailed mineralogy, vein textures, and absolute timing of mineralization exist – resulting in new questions about the deposit origin. This study attempts to relate these parameters through investigation of new U-Pb crystallization and Re-Os mineralization ages combined with detailed descriptions of vein textures to constrain the origin of the veins.