In contrast to the flat terrain surrounding Edmonton, the
Cooking Lake area has many round hills and small lakes. Geologists
call this type of terrain hummocky disintegration moraine (knob and
kettle topography). This was produced during the melting of the
vast continental glacier that once blanketed most of Alberta.
Hummocky disintegration moraine or dead ice moraine classically
is a closely spaced landscape feature that is relatively common on
the prairies, prairie potholes and prairie sloughs. There is almost
a complete lack of streams and the knobs have doughnut-like ridges
with the centre depressions filled with wetland vegetation. When
originally formed, they were mounds of glacial debris that had a
core of ice. As the ice melted, a depression was created in the
middle resulting in a doughnut shape.
This glacial erratic earthcache is an unusual feature in the
moraine. It is a large block of bedrock that was displaced from its
source some 250 to 300 km away. The block is a glacially
transported megablock of the Grand Rapids Sandstone transported
amazingly intact from its subcrops south of Fort McMurray. It would
have been approximately 4 km long and 12 m thick.
This type of moraine is a valuable environmental resource to
Alberta due to its irregular landforms and poor soil. It is great
for grazing, recreational purposes, and an important resting place
for migrating birds.
Reference: A Traveller's Guide to Geological
Wonders in Alberta - R. Mussieux & M. Nelson
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To log this cache:
1) You must post a picture in your log entry of yourself, your
group, or your GPS receiver in front of the sandstone.
2) You must also send an email indicating whether the sandstone
appears on one or both sides of the road. Also what is the
approximate maximum visible height of the exposed
sandstone. |
Please be very careful along the side of the road.