Basement stratigraphy in the Northway Junction area is composed of YTT metasedimentary and metavolcanic rocks. These have undergone intrusion by at least two plutonic suites that range in composition from granodiorite to granite. The older plutonic suite is represented by the western portion of the 112 – 105 Ma Dawson Range batholith, comprising medium to coarse-grained equigranular hornblende-biotite granite to granodiorite. The younger suite, comprising feldspar porphyritic monzonite, has been dated at 67-70 Ma. Host rocks for the Road Metal prospect consist of altered and unaltered variants of hornblende-biotite granite, quartz porphyry, and quartz monzonite.
The Road Metal prospect consists of porphyry-style Au-Cu-Bi mineralization hosted in argillic and phyllic-altered granites. Five plutonic phases have been recognized: (1) light gray coarse-grained hornblende-biotite granite; (2) medium gray sulfide-bearing granite; (3) bleached quartz porphyry; (4) medium to dark gray, unaltered monzonite or lamprophyre; and (5) altered fine-grained alaskite. Phases 1 and 2 likely represent pulses of batholithic emplacement. Phases 3, 4, and 5 likely represent the Late Cretaceous intrusive event. The texture of the Phase 4 dykes is reminiscent of outlying portions of “porphyry-style” systems.
Limited geological information is currently available for the Target 6 and Target 7 at Northway due to a complete dearth of outcrop. However, both targets appear to be hosted by medium to coarse-grained equigranular hornblende-biotite granite to granodiorite, with areas of quartz monzonite and a fine-grained, siliceous intrusive identified in rock chips from Geoprobe sampling. The interpretation of geological information obtained during the 2019 exploration programs is ongoing.