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.
