Abstract: Gladstone Creek hosts a productive placer mine and has been glaciated at least three times. Glaciations eroded bedrock and reworked surficial materials, depositing thick sequences of sediment in Gladstone valley, which were subsequently fluvially incised during deglaciation and non-glacial intervals. Fluvial incision and reworking concentrated detrital gold in coarse gravel units that commonly overly bedrock or false-bedrock surfaces. Identifying false-bedrock units in stratigraphy may help placer miners target economical gold deposits perched above the valley bottom.
Gold grain samples were collected from four gravel units. Characterization of gold grain morphology and laser ablation ICP-MS analysis indicate multiple sources of lode mineralization. Based on regional ice flow directions and the stratigraphic and geographic locations of the gold samples, gold is likely sourced from epithermal and gold-rich porphyry deposits associated with the Ruby Range batholith, and orogenic mineralization in the Kluane schist.

Authors: Cronmiller, D.C., Ward, B.C., Bond, J.D. and Layton-Matthews, D.

NTS Mapsheet(s): 115G07, 115G08

Citation: Cronmiller, D.C., Ward, B.C., Bond, J.D. and Layton-Matthews, D., 2019. Constraints on the evolution of placer deposits at Gladstone Creek, Yukon (NTS 115G/7, 8). In: Yukon Exploration and Geology 2018, K.E. MacFarlane (ed.), Yukon Geological Survey, p. 61–74.

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