The Finlayson Lake district contains >30 Mt of volcanogenic massive sulphide (VMS) mineralization, but has not been the focus of field-based research since the mid-2000s. We present herein preliminary fieldwork on Yukon-Tanana terrane (YTT) host rocks that are the groundwork for future petrologic, isotopic, and geochronologic studies of the stratigraphy and crustal evolution of the VMS deposits and YTT rocks in the Finlayson Lake region and other peri-Laurentian terranes of the northern Cordillera. During the summer of 2017, we logged seven drill holes that intersected the stratigraphic hanging walls and footwalls of the mafic-hosted Fyre Lake and felsic-hosted Kudz Ze Kayah and GP4F VMS deposits. The stratigraphic results generally reveal finely laminated to bedded mafic or felsic volcaniclastic rocks that are interbedded with clastic rocks or cut by intrusive rocks and reflect changes in depositional environments and tectonomagmatic regimes in the Late Devonian to Early Mississippian.
