Chapter 7: Overview of Carlin-Type Prospects of the Nadaleen Trend: A Yukon Analogue to Carlin-Type Gold Mineralization of the Great Basin
Michael J. Tucker, Julia C. Lane, Craig J.R. Hart, 2018. "Overview of Carlin-Type Prospects of the Nadaleen Trend: A Yukon Analogue to Carlin-Type Gold Mineralization of the Great Basin", Diversity in Carlin-Style Gold Deposits, John L. Muntean
Download citation file:
The Nadaleen trend is a 25-km-long alignment of recently discovered Carlin-type gold prospects located along the northern margin of the Selwyn basin in east-central Yukon Territory, Canada. These prospects are among the closest analogues to the large, Carlin-type gold deposits found in Nevada.
The Nadaleen trend is bound structurally to the south by the regional Dawson thrust and to the north by the Kathleen Lakes fault. The Dawson thrust marks the boundary between dominantly Neoproterozoic to Paleozoic slope and basin facies carbonate, siltstone, and clastic rocks of the Selwyn basin and strata of the Mackenzie platform. The Nadaleen trend contains numerous Carlin-type prospects, with the three largest being Conrad, Osiris, and Anubis. Carlin-type prospects of the Nadaleen trend are hosted in silty limestone and calcareous siliciclastic rocks along with isolated gabbroic dikes. Gold mineralization at Nadaleen is inferred to have accompanied decarbonatization of host limestone and subsequent silicification and/or brecciation. Typically, this was followed by late, open-space calcite, realgar, and orpiment. The prospects exhibit both structural and stratigraphic controls, with zones located near prominent fault and fold features. Gold is associated with elevated As, Hg, Sb, and Tl in mineralized zones. Several types of arsenian pyrite are found in mineralized zones, typically as rims around earlier barren pyrite cores or as <10-μm disseminations and aggregates.
Evidence from the Conrad zone suggests that Carlin-type gold mineralization occurred between 74.4 and 42 Ma. The tectonic and magmatic setting in this remote part of the Yukon during gold mineralization is poorly understood, with little or no evidence for contemporaneous regional magmatism or tectonism. While deposit-scale processes responsible for gold mineralization appear very similar for Carlin-type prospects in the Yukon and Carlin-type gold deposits in Nevada, whether the crustal-scale processes that formed these systems are similar remains enigmatic.