The White Channel gravel is the oldest gold deposit in the Klondike district. It is also the second richest after the creek gravels. Found locally on hills, it was referred to as “white channel gravels”, the “white wash”, or simply the “quartz drift” by early Klondike miners due to the predominant white quartz pebbles.
The significance of this deposit was not fully realized until nearly one year after its discovery , when George Carmack staked his famous Discovery Claim in Bonanza Creek, on August 17, 1896. The first bench claim in the White Channel Gravel was recorded on August 4, 1897, by Albert Lancaster on what is now called Gold Hill west of Eldorado Creek.
Shortly afterwards, William Cariboo Billy Diedrick, a seasoned prospector experienced at mining bench placers in the Cariboo goldfields of British Columbia, became convinced that the gold in the creeks came from a “lost channel” that ran through the Klondike hills. He eventually found gold on French Hill. When gold was found by Oliver Millet on Cheechako Hill as well, the miners soon realized there was a fortune in gold on the hilltops. Despite continuous mining over 100 years, its still a subject of on-going research.
The white channel gravel is considered one of the high level gravels in the Klondike. The channel extends as a discontinuous terrace, 50 to 100 metres above the present day Bonanza, El Dorado and Hunker creeks. Significant deposits can also be found on Allgold, Quartz and Dominion creeks, with minor presence along the Indian river and some other localities. The deposit generally increases in thickness away from King Solomon Dome, reaching a preserved thickness of approximately 40 metres.
The White Channel Gravel formed millions of years before the Last Ice Age that created the ice-locked subcontinent called Beringia. During the Miocene (about 5 million years ago), the Klondike area was much warmer and received more precipitation. This resulted in a debris covered peneplain with low rounded hills and the white channel gravel began to accumulate in stream valleys that radiate outwards from the current King Solomon Dome.
This whole region laid at a much lower elevation than it does today and the Yukon River flowed South into the Gulf of Alaska. The Klondike River likely flowed into the Stewart River, or East into the Tintina Trench. During that time, the White Channel gravel was deposited in braided streams radiating from the King Dome.
With the onset of glaciations in the Yukon, approximately 2.5 million years ago, regional river drainage patterns reversed and the Yukon River was diverted North and West into Alaska along its present-day route. During this time the forests were probably replaced by grasslands.
As the glaciers expanded beyond the Ogilvie Mountains (Northeast), rivers draining from the ice brought with them the Klondike Gravel. Depositions of the glacial outwash on top of the White Channel Gravel led to the demise of the White Channel Gravel. As the pre-Reid glaciation ended, there was an increase in precipitation, however the sediment delivery remained low because the vegetation stabilized the river valleys. As a consequence, there was a lowering of the base level which favoured the erosion of the white channel gravel.
This, combined with an uplift of the whole area, caused the streams to flow faster and to carve more deeply into the surrounding landscape. Eventually, benches of White Channel gravel were left high above the present Hunker, Bear and Bonanza creek valleys. These new streams meandered back and forth in the valleys and carried away roe than half of the White Channel Gravel, but apparently left most of the gold behind.
Gold in the White Channel Gravel is concentrated on bedrock and within the first 1 to 2 metres of the gravel, decreasing rapidly up section, with a pay streak that is approximately 100 metres wide. The gold has a fineness ranging from 700 to 850. McConnel thought that practically most of the gold in the White Channel Gravel came from Quartz veins, an idea supported by the data and he also noted that the distribution of the White Channel Gravel is marked by a trail of gold, even when the gravel has been eroded.
The gold present in Bonanza and Hunker creeks comes from the erosion of the Channel. The explanation is that the erosion of the White Channel Gravel caused the concentration of the gold in the creeks due to the lowering of the base level at the end of the pre-Reid glaciation. As the placer gravitated to a lower elevation it became more concentrated because of the reduction in accommodation space.
Mass balance calculations indicate that anywhere from 200 to 2,000 cubic kilometres of rock were eroded tp produce the amount of gold recovered from the Klondike gold fields. A seemingly insignificant trace amount of gold in this quantity of bedrock would be sufficient to account for all the gold recovered implying there is no mother lode. Coild there be other areas where the White Channel Gravel has not yet been found? Perhaps, and with it, a fortune in gold on the hilltops waiting to be claimed!
For those that are fans of the TV Show Gold Rush, maverick gold mining legend Tony Beets is currently mining White Channel Gravel.