This
location is reached by a moderate to strenuous hike into the Dinkey
Lakes Wilderness. The coordinates are at an elevation of about 8800
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 will make the
EarthCache inaccessible.
The Dinkey Lakes Wilderness has been covered in glaciers
numerous times. Erosion by the glaciers scoured the valley down to
the 104 to 90 million year old Dinkey Creek Pluton (see
EarthCache). Since then, erosion has been redistributing material.
Along steeper slopes, the creek eroded material. Along flatter
sections, the creek slowed deposited material and meandering.
It is on this flat topography a river or stream slows and begins
to meander. In areas of low slope, the path of a river begins to
wander back and forth creating meanders, or curves. Along each
curve, the flow of the river is constantly eroding the outside bank
of the meander, while at the same time depositing material on the
inside. This is because the area of fastest flow in the river is
forced to the outside bank on the curves and the slowest flow is on
the inside. Faster water carries more sediment causing the erosion.
The slower water is unable to carry as much sediment, so some
sediment drops out of the water. The result is a steep bank on the
outer edge of a meander and a gentle slope on the inner edge.
Over time, meanders get larger more pronounced as the outer edge
is eroded away and the inner edge has material deposited on it.
Given enough time, the meanders could get so curvy that they bend
back and touch itself creating an oxbow lake. An animation of river
meander formation can be found at
http://www.cleo.net.uk/resources/displayframe.php?src=309/consultants_resources%2F_files%2Fmeander4.swf
However, in a mountainous area such as this, where annual spring
runoff is high, the creek likely has no chance to form an oxbow
lake. The meander is likely bypassed during the spring flooding
leaving an open area that is probably quickly filled in.
Logging requirements:
Send me a note with :
- The text "GC30XM0 Dinkey Creek Meanders" on the first line
- The number of people in your group (put in the log as
well).
- How well does this meander match the description?
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.
- All images from Prof. Stephen A. Nelson, Tulane
University.
http://www.yosemite.ca.us/library/geology_of_yosemite_valley/