The Penokee and Gogebic Range which
extends 80 miles across eastern Wisconsin and western Michigan was
created about 1.6 billion years ago during a mountain building
episode. This area once stood four miles above sea level, but after
millions of years of erosion and at least four glacial ice
advances, this range now stands one-third mile above sea
level.
The rock below this terrain is marine sediment deposited
here by an ancient sea that covered this region nearly two billion
years ago. Relentless folding and faulting ruptured the earth’s
surface forcing rocks like this one upward.
These rocky ridges and valleys are also known as the Great
Divide…which parts the waters that flow north to Lake Superior,
from the waters that flow south to the Mississippi River.
The landscape encompasses a series of valleys and ridges.
Valleys are visible remains of faulting activity and known as gaps.
The terrain has held a key to a wealth of mineral resources that
are discovered and exploited by man in the 18th and early 19th
century.
Follow the stairway up to the viewing platforms and take a few
moments to relax and soak up the scenery!
Beneath this board walk runs a spring. The bedrock is close to
the surface and the soil layer is less than 20 inches thick. The
water runs along the surface and disappears in rock fractures or
soil pockets only to appear again downstream. Water runs year round
from springs deep within the rock formation.
“It should be borne in mind that the whole region is not
only covered so thickly with trees that no distant view can be had
without climbing trees, but the drift often conceals the rocks over
a large proportion even of the elevated ridges. In addition, the
rocks themselves previous to the era of the drift have been the
sport of giant forces which tossed and tilted them about at various
angles and elevations realizing the fable of Atlas.”
-Colonel Charles Whittlesey, 1849
TO LOG THIS
CACHE:
1) How many tons of taconite iron ore are estimated to still be in
the Penokee-Gogebic Range?
2) Valleys are visible remains of faulting
activity called gaps…how many “gaps” can be seen from this vantage
point?
E-mail me the
answer(s)
HERE.