This is not your typical geocache. It is an
Earthcache. You will not find a "cache container" at the
listed coordinates. An Earthcache is designed to bring you to
a geological feature and educate you. Of course, as with any
geocache you can earn a "find" if you complete the
requirements listed at the bottom of the page.
THE BIG PICTURE
The Niagara Escarpment is a long escarpment, or cuesta, in
the United States and Canada that runs westward from New York
State, through Ontario, Michigan, Wisconsin and Illinois.
Thus, Lannon is only a small segment of this extensive geologic
structure. It is composed of the Lockport geological formation of
Silurian age, and is similar to the Onondaga geological
formation, which runs parallel to it and just to the south,
through the western portion of New York and southern Ontario. The escarpment is most
famous as the cliff over which the Niagara River plunges to form Niagara Falls, for which it is named.
The Niagara Escarpment is the most prominent of several
escarpments formed in the bedrock of the Great Lakes. It is
traceable from its easternmost point in New York State, starting
well east of the Genesee River Valley near Rochester, creating one small and two
large waterfalls on the Genesee River in that city, thence running
westwards to the Niagara River forming a deep gorge north of
Niagara Falls, which itself cascades over the
escarpment. In Southern Ontario it stretches along the Niagara
Peninsula hugging close to the Lake Ontario shore near the cities
of St.
Catharines and Hamilton and Milton where it takes a sharp turn north
toward Georgian Bay. It then follows the Georgian Bay
shore northwestwards to form the spine of the Bruce Peninsula, Manitoulin, St. Joseph Island and other islands located
in northern Lake Huron where it turns westerwards into
the Upper Peninsula of northern Michigan, south of Sault Ste. Marie. It then extends
southwards into Wisconsin following the Door Peninsula and then more inland from the
western coast of Lake Michigan and Milwaukee (including
Lannon) ending northwest of Chicago near the Wisconsin-Illinois
border. The diagram below notes only some of the more signigicant
portions of the Niagara Escarpment, but not its complete
extent.
ROCK FORMATION
Study of rock exposures and drillholes demonstrates that there
is no displacement of the rock layers at the escarpment: this is
not a fault line but the result of unequal erosion.
The Niagara Escarpment has a caprock of dolomitic limestone
("dolostone") which is more resistant and overlies
weaker, more easily eroded shale as a weathering-resistant "cap". In other words, the
escarpment formed over millions of years through a process of
differential erosion of rocks of different hardnesses. Through time
the soft rocks weather away or erode by the action of streams. The
gradual removal of the soft rocks undercuts the resistant caprock,
leaving a cliff or escarpment. The erosional process is most
readily seen at Niagara Falls, where the river has quickened
the process. It can also be seen on the three waterfalls of the Genesee River at Rochester, New York (additional resistant
rock layers make more than one escarpment in some places). Also, in
some places thick glacial deposits conceal the Niagara Escarpment,
such as north of Georgetown, Ontario, where it actually
continues under glacial till and
reappears farther north.
The dolostone cap was laid down as sediment on the floor of a
marine environment. In Michigan, behind the escarpment, the
cuesta capstone slopes gently to form a wide basin, the
floor of an Ordovician-Silurian tropical sea. There the
constant depositing of minute shells and fragments of
biologically-generated calcium carbonate, mixed with sediment
washing in by erosion of the virtually lifeless landmasses
eventually formed a limestone layer. In the Silurian some magnesium
substituted for some of the calcium in the carbonates, slowly
forming harder sedimentary strata in the same fashion. Worldwide
sea levels were at their all-time maximum in the Ordovician; as the
sea retreated, erosion inevitably began.
LOCAL IMPORTANCE
After Lannon was settles in the 1830's limestone was mined and
used for buildings and roads. The stone was easy mined near the
earths surface and broke off into usable slabs. Soon thereafter, it
was commercially mined. By 1855, there were more than a dozen
quarries. Back then all jobs were associated with the dolostone or
limestone industry. In fact, before Lannon got its present day name
it was called, Stone City. Today only 20% of local
jobs rely on the quarry companies.
As previously noted, the Niagara Escarpment is an immense
geologic formation. However, all dolostone was not created with
similar properties. There is a key to the success of the
Lannon stone industry. Lannon stone is the strongest and most dense
of all limestone found in North America. This makes it highly
sought after around the world.
There are many active quarries in the area. The quarry at
Menomonee County Park is now called, Trout Lake. A spring was
struck and the quarry pit filled with water submerging a large
crane at the bottom. There is a large piece of rusting equipment
that rests on the shore of the south side of the lake.
There are other uses for limestone, as well. See my other
Earthcache located in Menomonee Falls called, Menomonee Falls Lime
Kiln, GC1KRDT, for more details.
LOGGING THIS
EARTHCACHE
In order to log this earthcache you must
complete task number one:
1. Email me the answers to
these questions:
a. What major geological
formation underlies Lannon?
b. Where does this feature
start and end? Name the states, please.
c. The Niagara Escarpment
caprock stone is called what? It is two words.
d. When was Lannon
settled?
e. What was Lannon's first
name?
2. Optional: Take a self photo
with your GPS or your team with a GPS near ground zero with
Trout Lake in the background. Then post the photo with your
log. Have at least one person and a GPS in the photo. If you
are geocaching alone, hold you camera at arms length to take a self
photo, please.
Failure to complete the task as listed
above (emailing the answers) will result in log deletion without
notice.
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References:
http://www.slahs.org/history/local/lannon/history/stone_quarry.htm
http://www.lawnproducts.com/stoneusa/stoneusaintro.htm
http://en.wikipedia.org/wiki/Niagara_Escarpment