Abstract: New stratigraphic interpretations of exposures at Dago, Preido and Paradise hills on lower Hunker Creek suggest a more complex stratigraphic framework for the development of high-level bench gravels in the Klondike than has been previously put forward. A highly-altered gravel has formerly been interpreted to be part of the lower White Channel Gravel sequence and its degree of alteration attributed to enhanced groundwater diagenesis near the bedrock contact. New mining exposures indicate this altered gravel, here informally termed ‘Paradise gravel’, is laterally extensive and the alteration is not restricted to the bedrock interface. Furthermore, a cross-section reconstruction shows the White Channel Gravel is stratigraphically inset into the Paradise gravel. Alteration of the Paradise gravel is possibly a function of pedogenesis, suggesting a period of landscape stability followed its deposition. This pattern of sedimentation and potential stability was repeated within the lower White Channel Gravel and recorded by a zone of clay alteration and iron oxidation.
Economically, the Paradise gravel is significant. At each locality investigated, the primary pay streak occurs in the Paradise gravel. Conversely, the White Channel Gravel is only economic where it sufficiently erodes and reworks the Paradise gravel. In nearby drainages, including upper Hunker Creek, the White Channel Gravel more completely reworks Paradise gravel to bedrock and becomes the pay unit. Preservation of the Paradise gravel documented in lower Hunker Creek may be due to its broad valley morphology. Future studies are recommended on the sedimentology of the Paradise gravel to understand gold distribution both vertically and within the pay channel(s). In addition, research into the pedogenic alteration could provide information on past climates during the Neogene.

Authors: J.D. Bond

NTS Mapsheet(s): 116B03, 116O14

Citation: Bond, J.D., 2016. The Paradise gravel: Evidence for a pre-White Channel Gravel in the Klondike. In: Yukon Exploration and Geology 2015, K.E. MacFarlane and M.G. Nordling (eds.), Yukon Geological Survey, p. 29-42.

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