Haliburton County, in which the Hawk Lake Log Chute is located,
boasts some 600 lakes, numerous streams and rivers and countless
wetlands. The high number of water bodies in this area is directly
related to the nature of the underlying bedrock.
The Canadian Shield
The bedrock in this area is part of the Canadian Shield. The
Canadian Shield is a large geographic area in eastern and central
Canada composed of bare rock dating to the Precambrian era (between
4.5 billion and 540 million years ago). It is also called the
Precambrian Shield, or Laurentian Shield. In total it covers
approximately 8 million square kilometers. The Canadian Shield is
made up of some of the planet's oldest rock, largely granite and
gneiss (pronounced "nice"). There is virtually no open space within
the structure of this type of rock - less than 0.01%!
The well sealed bedrock bottoms of the lakes and wetlands of the
Haliburton Highlands keeps the water on the surface and very little
seeps down into the bedrock. This area is also characterized by a
very thin layer of soil which means that the topography of the area
is determined not by mounds of soil but by the bedrock underneath.
The well-defined valley in which the Hawk Lake Log Chute is an
excellent example of how the bedrock determines the flow of water.
Both it and the Kinnesis River were shaped by two geologic events -
faults and glaciers.
Faults appeared hundreds of millions of years ago. As the
earth's crust cracked it shifted and the rock along these fault
lines moved and was subjected to much grinding and crushing. This
resulted in splintered rock accumulating within the fault zone
compared to the solid rock outside of the fault line. Now comes the
action of glaciers. Between 78,000 and 10,000 years ago, much of
Canada was covered in up to three kilometers of ice. As the glacier
moved through the area, it dug deep into the fractured rock moving
it out of the fault zone leaving behind the steep sided gorge in
which the Kinnesis River flows.
Logging Requirements:
To log this Earthcache, perform the following tasks and
determine the answers to the questions below. Email me your
answers, DO NOT include them with your Found It log.
- Go to the posted co-ordinates where you will find an
information panel titled "The Land - Rock and Water". In which
direction is the fault along the Kinnesis Valley lined up?
- What other lake basin was formed by glaciers plucking out
broken rock along a long, narrow fault zone?
- What type of action can result in the widening of the valley?
The answer to this question is not on the information panel - you
will have to come up with the answer yourself. (Hint: "Brrr - it's
cold" said Jack _____).
- Proceed to Reference Point 1 and record your elevation.
- Proceed to Reference Point 2 and record your elevation. For the
sake of argument, let's assume that it takes 10 years to erode 1 mm
of gneiss. How long would it take to erode this cliff down to
Reference Point 1?
Optional: Post an original image of the Kinnesis Valley.
Feel free to include yourself and any other members of your group,
but not your GPS, in the image.
