The Use of Stream Sediment Mineral Chemistry and U/Pb Geochronology for Regional Targeting: A Case Study from Yukon with Implications for Porphyry Cu and Orogenic Au Deposit Exploration

Stream sediments can provide extensive information about rocks from their catchments. Heavy mineral concentrates from stream sediments could be used during regional targeting when exploring for a range of different deposit types. Here, we present an example of using mineral chemistry coupled with U/Pb geochronology for zircons, titanites, and rutiles from a regional stream sediment study in Yukon with implications for porphyry Cu and orogenic Au deposit exploration in the region and globally. In this region, the location of the porphyry Cu deposit was determined based on rutile compositions, while an orogenic Au signature was identified primarily in titanite and rutile chemistry. The locations identified based on stream sediment mineral chemistry corresponded to the approximate locations of the Casino porphyry Cu and Coffee orogenic Au deposits. Other potential targets for follow-up exploration are also highlighted. This study accentuates that the addition of trace element mineral chemistry and U/Pb geochronology analyses to an exploration program provides substantial benefits in terms of constraining the ages of basement and host rocks and prioritising targets. The application of heavy mineral chemistry from stream sediments used for regional-scale targeting, followed by rock chip sampling and analysis at the camp scale, can provide significant exploration results, as demonstrated in this study.