Geological Time Scale is a calender base system that works with time periods. The scale divides time into different time periods as we do today with years, decades, and millenniums. This is done by studying the layers and fossils left behind by organisms before us. The youngest sediments is the layer closest to the surface, and the last layer under all the other layers in the oldest.
Calumet Geological History
The history of the Calumet Area extends from Southern Cook
County, Illinois all the way to LaPorte County, Indiana. Hundreds of Millions of
years ago (Eons ago) the Calumet Area was below sea level. Much later Dinosaurs
and then later mammoths ruled over this land. The great lands changed over time
due to physical forces that changed the globe. The movement of the earth’s
crust raised and lowered the land (Schoon p.3). Mighty glaciers later invaded
the land many times (Schoon p.3). Lastly, the powerful winds eroded sand from
different places (Schoon p.3).
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| http://igs.indiana.edu/FossilsAndTime/LakeMichigan.cfm |
The three great shorelines were discovered in the 1897 by a
geologist named Frank Leverett they were: Glenwood, Calumet, and Toleston.
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Frank Leverett
http://um2017.org/faculty-history/faculty/frank-leverett |
The Rock-Recorded History
The bedrock under the soil and sediment contains dozens of
horizontal layers of limestone, sandstone, shale, and dolomite (Schoon p.12).
Sandstone forms underwater near a shore, unlike the shale, limestone and dolomite
they form far from shore (Schoon p.13). No igneous or metamorphic rocks can be found
in the Calumet Area except the sedimentary rocks, and pebbles, cobbles, and
boulders that were left behind by the northern Glaciers (Schoon p. 13). The
sedimentary rocks underneath the calumet Area are about 4,000 feet thick
(Schoon p.13). At the surface there is about 25-350 feet of glacial till and lake
sediment (Schoon p.13). During the Devonian
period the calumet area was covered by sea water and the top surface layer was
covered with shale (Schoon p.13). During the Silurian period much of the surface
was covered in limestone which later transformed to dolomite (Schoon p.13). During the Ordovician period the surface
was covered with shale, sandstone, limestone, and dolomite (Schoon p.13). During the Cambrian period the later
was primarily sandstone (p.13). Lastly, during the Pre-Cambrian period the
oldest rock found in the calumet area is granite which is formed by slow
cooling of magma (Schoon p.13).
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Calumet Area Bedrock:
Kenneth J. Schoon Calumet Beginnings |
Dinosaurs and Other Extraordinary Animals
Dinosaurs ruled over our land during the Jurassic,
Cretaceous, and Triassic Periods, but sadly during the Ice age the glaciers
destroyed the evidence of dinosaurs ever living in the Calumet area. During the last Ice Age some mammals lived in Indiana,“Among these were the American Mastodon, Jefferson’s
mammoth, Harlan’s musk ox, the stag moose, saber-toothed tiger, and giant
beaver (Schoon p.15-16)”.
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Apatosaurus
http://guardianlv.com/wp-content/uploads/2013/12/Dinosaurs-Extinction-Proof-Finally-Discovered1.jpg |
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Mammoth
http://science.psu.edu/alert/images/Schuster7Lrg.jpg |
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Saber-Toother Tiger
http://www.joevenusartist.com/Images/Saber-Tooth-Cat.jpg |
Evidence for the Ice Age
The evidence of the ice age being part of our lands is all
around us. The evidence is till, this sediment that can be found by glaciers
today. “Till is a mixture of clay, silt, sand, pebbles, and even boulders that
has been deposited directly by glaciers (Schoon p.16)”.
.jpg) |
From Ice Age the Movie
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| All the information written comes from this Book- Kenneth J. Schoon: Calumet Beginnings |
