Zircon Age and Oxidation State Estimates for Plutons Spatially Associated with Mineral Deposits Along the Kettle Detachment Fault in the Orient Quadrangle, Northeastern Washington

Critical minerals are essential to national security, economic stability, and the transition to clean energy, making them a priority in geologic research and exploration. To better understand the magmatic conditions associated with critical mineral concentration, zircon, a recorder of magmatic history, was analyzed using U-Pb geochronology and trace element geochemistry. The analyses were conducted via LASS-ICP-MS on ten plutonic samples from the Orient quadrangle in northeastern Washington and one sample from the Adams Mountain and Hunter (AMH) quadrangles to constrain the geological processes leading to ore deposit formation, including tungsten (W). This region, cut by the Kettle Detachment fault, is known for its economic mineral occurrences and inactive mines, such as the Talisman mine, making it an ideal area for studying ore-forming processes and evaluating future resource benefaction. Samples collected from the hanging wall of the Kettle Detachment fault include the Barstow granodiorite (OR1: 103.8 ± 0.3 Ma), a mafic intrusive near Kettle Falls (OR2: 51.3 ± 0.2 Ma), the Orient granite (OR5: 51.5 ± 0.2 Ma), an intermediate intrusive near Fifteen Mile Creek Pluton (OR7: 51.3 ± 0.3 Ma), a granite porphyry from the Fifteen Mile Creek Pluton (OR8: 51.2 ± 0.2 Ma), a Deep Creek biotite quartz monzonite (OR9: 51.5 ± 0.2 Ma), and a quartz monzonite near the Germania Mine in the AMH quadrangles (CC36: 104.2 ± 0.7 Ma) . The footwall ix samples include a pegmatite intruding through pre-Tertiary paragneiss and marble (OR12: 85.1 ± 0.2 Ma), an equigranular orthogneiss (OR16: 108.1 ± 0.4 Ma), and Kerry Creek quartz monzonite (OR17: 51.8 ± 0.2 Ma). The hanging wall samples yielded ΔFMQ values between +0.0 and +2.5, while the footwall yielded lower values between -2.0 and +0.0. OR17, an Eocene pluton, located closest to the Talisman mine, yielded a higher ΔFMQ value compared to the Cretaceous plutons associated with W-deposits in the AMH quadrangles, which exhibit low ΔFMQ values (< +0.5), suggesting that different magmatic processes may have led to the deposits in the two regions. Furthermore, OR17 exhibits higher degrees of fractionation than the other samples in the suite, which is highly favorable for the concentration of elements such as W. The Orient quadrangle experienced major Eocene magmatism within only 0.6 ± 0 2 Ma in the Eocene, coincident with major regional extension associated with the accretion of Siletzia.