UBC Undergraduate Research

Uranium-Lead, Argon-Argon, and Lead Isotopic Constraints of Magmatism and Associated Mineralization within the Stikine Terrane, on the Williams Gold Property, North Central British Columbia Bayliss, Sandra M.

Abstract

Stikinia is a tectonostratigraphic terrane in the Canadian Cordillera comprised of the Early Permian Asitka Group, the Late Triassic Stuhini Group and the Early to Middle Jurassic Hazelton Group. William’s Gold property which coincides with the study area is located on the east-northeast margin of the Stikine terrane within a fault mosaic of Devonian to Permian Asitka Group carbonates and volcanic and sedimentary rocks of the Stuhini Group. The primary purpose of this study is to determine the timing of mineralization and the absolute ages of the intrusions within the Williams west region of the William’s Gold property. This study attempts to correlate mesothermal gold veining and Cu-Au porphyry style mineralization from the study area with mineralization that has occurred approximately 100km southeast at Kemess Mine. U-Pb, Ar-Ar geochronology and Pb isotopic studies were used to determine the ages and isotopic signatures of rocks located within the study area. Four samples of quartz monzonite and one sample of a feldspar porphyry gave U-Pb crystallization ages ranging from 221.4 to 183.6 Ma. Two samples G090062, and G090063 contained cores that cluster between 230 and 260 Ma and 330 and 380 Ma. The oldest gave an age of 420Ma. The presence of older cores suggests that the intrusion passed through older basement rocks, possibly the Paleozic Stikine Assemblage. A sample of alteration sericite from the T-bill prospect that is believed to occur syn-mineralization was dated using the Ar-Ar method and returned an inverse isochron age of 194.6 +/-3.5 Ma. The age of the sericite alteration did not correspond to the ages of the five intrusive units analyzed during this study. This suggests that the mineralization at the T-bill prospect was likely not genetically related to any of the intrusions dated in this study.

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Attribution-NonCommercial-NoDerivatives 4.0 International