Mystery Lake is reached by a moderate to strenuous hike into the
Dinkey Lakes Wilderness. It is approximately 1.5 miles from the
parking area at an elevation of about 9000 feet. The parking area
is accessible by unpaved Forest Service access roads. The roads do
get pretty rough, so a high clearance vehicle would be a very good
idea. Winter snows and spring runoff will make the EarthCache
inaccessible. Even after the snow melts, the location will be
difficult to get to as it is in the stream channel. The best time
to visit the cache is in late summer and autumn before the snows
come.
The Dinkey Lakes Wilderness has been covered in glaciers
numerous times. Erosion from the glaciers created a few cirques
(see
South Lake – A Cirque ) that later became tarns (See
South Lake – A Cirque ). Mystery Lake is one of these
tarns.
The outfall of Mystery Lake flows over the 104 to
90 million year old
Dinkey Dome Pluton and down a relatively steep slope. During
the spring runoff, water carries sediment down the streambed over
the bare bedrock.
Potholes form where a rock is spun around in the same spot by
circular eddy of water. The constant abrasion begins to wear away
the bedrock into a hole. Periodically a rock falls into the hole
and is spun around in the hole increasing the erosion rate. The
rock that spins in the hole is called a grinder. As one grinder
wears away another rolls in to fill its place. Once started, the
feature is self-reinforcing as the hole creates an even
Image from (Jennifer Mikolajczyk , University of Wisconsin at
Eau Claire, Interstate Park,
http://www.uwec.edu/jolhm/Interstate2006/potholes.htm)
Logging requirements:
Send me a note with :
- The text "GC30XPD Mystery Lake Outfall Potholes " on the first
line
- The number of people in your group (put in the log as
well).
- What are the dimensions of the pothole(s) near here?
- Describe the size of the grinder in the pothole? ?
The above information was compiled from the
following sources:
- Petford, N., Cruden, A., McCaffrey, K and
Vigneresse, J-L., Granite magma formation, transport and
emplacement in the Earth's crust, Nature, V. 408, p. 669-673,
December 2000.
- Jennifer Mikolajczyk ,
University of Wisconsin at Eau Claire, Interstate Park,
http://www.uwec.edu/jolhm/Interstate2006/potholes.htm