Photos of Miles Canyon - Whitehorse, Yukon
An Explorer's Guide to Miles Canyon
The main body of this interpretive sign at the canyon parking lot reads:
"Miles Canyon Basalts
The basaltic lava exposed by Miles Canyon originated from a low volcanic vent approximately 8 km to the south [between Golden Horn and Mount Sima]. This lava flowed into the Yukon River valley about 8.5 million years ago. Drilling near Whitehorse rapids shows that the layer of lava reaches 110 meters thick. Only the top 10 meters of this layer is currently visible at the bridge. Prior to the building of the Whitehorse dam in 1959 [actually 1958], the water level was about 10 meters lower, exposing much more of the lava.
The Yukon River generally flows through glacial deposits in this part of the Yukon. These silts, sands and gravels are soft, allowing the river to meander from side to side in the valley bottom, sometimes splitting to form braids. This meandering and braiding effect slows the river current. In comparison, the basalt rock here in the Canyon is much more resistent to lateral erosion and does not allow the river to meander. This channels the water and increases the velocity significantly.
This photograph is © 2016 by Murray Lundberg, and is not to be copied without express permission.