A few notes on getting here. This EC is located at the top of Harrison Grind on Mount Agassiz.
1. You can hike up the Harrison Grind starting at the waypoint in Harrison Hot Springs. It's approximately 10km return to the lookout, and an elevation gain of 750m (it's a grind for sure, and depending on your fitness level can take 4-5 hrs).
2. With an off road vehicle or 4x4 you can get to within ~1km by driving up Mount Woodside FSR (13km each way - see waypoints) to Campbell Lake. The last 1km you will have to hike. The trail is well defined and marked, with minimal elevation change and a short but tricky boulder field to cross. At time of publication there was no active logging in this area however as always that may change.
Be sure of your ability to navigate either route before attempting to access GZ.
Roche Moutonnée
Roche Moutonnée, is french for Sheepsback, and was first coined by french explorer Horace-Bénédict de Saussure in the 1700s.
Their appearance is usually a smooth, rounded back pointing uphill, while their downhill face is rugged and often steep.
Generally they are considered to have been formed during glacial movement, however they may also have been a pre-glacial feature that was very resistant to being eroded unlike the rest of the bedrock around them.
Formation
Roche moutonnée is a glacial errosion formation (unlike drumlins which can be similar in apearance but are a depositional formation).
As a glacier advances it encounters the hard bedrock, moving around and over it.
The ice, together with the rocks it is pushing and dragging along, scrape the rock smooth, sometimes causing striations in the rock.
As the glacier moves over the down side it plucks away soft and loose rock creating a steeper edge. Some of the ice melts into the cracks and when it refreezes and attaches to the glacier, the pressure from further movement then fractures additional rocks off the edge.
Stoss is the end that faces the direction the glacier comes from, and Lee is the down-ice side. In the case of a roche moutonnée the Stoss is the gently sloping side and the Lee is the blunt, high side.
Diagram courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder
To complete this earth cache, please email / message the CO with the answers... do not post them in the logs or unfortunately the log will be deleted.
- As the glacier contacts the Stoss first, the direction of advancement can be determined when viewing a roche moutonnée. Which compass direction do you believe the glacier that formed this roche moutonnée was moving in?
- How many distinct roche moutonnée are in this location?
- What is the approximate length, width and height of both the longest and shortest of these geological features?
- Post a photo, selfie or includes your caching name (on paper, or some other unique way), with the farthest west roche moutonnée or with Harrison Lake in the background. Be sure not to post photos that answers to the above can be derived from or the log may be removed.
Note: You do not need to wait for a response from CO in order to log your find.
Sources:
Encyclopedia Brittanica
National Snow and Ice Data Center