Abstract: New U-Pb zircon dates (SHRIMP and LA-ICPMS) from granitoid rocks of the Aishihik batholith indicate a range of ca. 190-180 Ma for the Long Lake plutonic suite, as previously indicated by less precise, multi-grain TIMS dates. None of the phases in the Aishihik batholith are as old as the Minto suite to the north, therefore limiting the potential for Minto-style Cu-Au-Ag mineralization in the batholith. However, local occurrences of apparently shallow-level intrusions suggest that parts of the Aishihik batholith may present suitable targets for more typical porphyry Cu-Au mineralization. LA-ICPMS U-Pb zircon dating of two orthogneiss samples from the western margin of the Aishihik batholith yielded Early Mississippian protolith ages akin to the Simpson Range plutonic suite (Yukon-Tanana terrane), and Jurassic overgrowths consistent with partial melting related to intrusion of the Aishihik batholith.

Authors: N.L. Joyce, M. Colpron, M.M. Allan, P.J. Sack, J.L. Crowley and J.B. Chapman

NTS Mapsheet(s): 115H01, 115H06, 115H07, 115H10, 115H14, 115H15, 115H16

Citation: Joyce, N.L., Colpron, M., Allan, M.M, Sack, P.J., Crowley, J.L. and Chapman J.B., 2016. New U-Pb zircon dates from the Aishihik batholith, southern Yukon. In: Yukon Exploration and Geology 2015, K.E. MacFarlane and M.G. Nordling (eds.), Yukon Geological Survey, p. 131-149.

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