SONORA PALEOCHANNEL
placers are strewn with trenches, prospect pits, and numerous mineralized shows and occurrences with moderate to high Au, Te, and Cu values. Several holes in 2010 were apparently drilled further southeast to moderate depths and encountered min- eralization at depth.
Placer Workings
George Wilson’s mechanized, one-man placer operations have produced moderate amounts of gold from the lower one-kilo- meter of Sonora Gulch. Since 1995, George has developed bench gravels beneath the lowermost slopes of Sonora Gulch’s steep banks. Slumping of thawed permafrost within black, organic mud capping the host gravels can be problematic (Photo #1).
George Wilson had widened the gulch by 20 meters or so on the eastern bank of Sonora Gulch, towards the upper part of his claims, allowing him to methodically excavate panels parallel to the axis of the gulch (Photo #2).
JV (Straus-Trojan-Great Plains-Molycorp) re-staked it as the DP 1-24 claims and conducted geological, geochemical, and trenching surveys into 1970. In 1974 the DC Syndicate (Dome-Cominco) re-staked the area as the NADA 1-24 claims and fol- lowed up with geological and geochemical surveys into 1975.
The Swede 1-6 lode claims on Sonora
Gulch were optioned in 1975 to a Hudson Bay-Tombill-Minorco (HBTM) consortium. The HBTM consortium and successors added 128 SAM claims and conducted geological, geochemical, and electromag- netic, trenching, and drilling surveys into 1983. Hudson Bay maintained the property through cash-in-lieu payments until 1997.
The SAM claims were optioned, mapped,
trenched, and resampled in 1997 and 1998. These trenches cut intrusive-hosted mineralization of the “Gold Vein System” southeast of the upper airstrip and the “Tetradymite Vein System” to the northeast but were returned in 1999. A 2001 property visit recovered high gold values and trace element geochemistry similar to the Pogo deposit (Schulze, 2004).
Geologic mapping, sampling, and drill- ing of the Sonora area from 2005 to 2010 resulted in new Au-Cu discoveries east and south of Sonora Gulch. Comparisons have been made with the Casino Au-Cu-Mo deposit (Schulze, 2009). The headwater areas of the Sonora Gulch and Klines Gulch
Additional placer workings and areas of placer disturbance occur in nearby portions of Hayes Creek, in Klines Gulch, and in lesser nearby drainages (Figures 4 and 5). Klines Gulch supported a sizeable population of placer miners in past decades, attested by numerous large and small dumps and the remnant of a two kilometer ditch built to bring water from upper Hayes Creek to the Klines Gulch.
Regional and district economic geology
Regional and District Bedrock Lithologies
The Yukon-Tanana terrane, a belt of Late Devonian to Late Permian metasediments
Photo #1. Slumping of thawing permafrost developed in black, organic mud capping the host gravels.
www.aipg.org
Photo #2. In-place panel of pay gravel being excavated from Sonora paleochannel by George Wilson on 30 July, 2010. Location is the same as sample 100730.04, Table 1, in the center reach of Sonora Gulch (Figure 6). See also detail of pay gravel (Photo #5).
Jul.Aug.Sep 2024 • TPG 11
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