EXPLORING COMPETING GOLD SYSTEM MODELS IN THE VALDEZ CREEK REGION, CLEARWATER MOUNTAINS, ALASKA
Constraining mechanisms of gold mineralization through a geochronological and geochemical framework with structural analysis provides a robust tool to determine dominant ore-forming mechanisms and provenances. We hypothesize a system model in which metamorphic fluids generated from the dehydroxylation of chlorite occurred simultaneously with shearing along the Valdez Creek shear zone. Preliminary 206Pb/238U zircon data collected from the alkali pluton suite and the placer system indicates gold deposition was localized above alkaline plutons in the region. These data suggest the placer gold has a spatial association with the ca. 89 Ma plutonic suite in the footwall but is temporally related to crustal thickening 30 Myr later. We posit auriferous fluids were concentrated within or proximal to rigid intrusion(s), coinciding with vein development and fluid channelization, similar in process to the Juneau gold belt. White mica 40Ar/39Ar geochronology from gold-bearing quartz veins will be vital to strengthen the proposed link between the origins of gold enrichment and the Valdez Creek shear zone’s influence on economically viable gold system models.