Tuesday, January 27, 2015

Ohio During the Quaternary Period

Amanda Crawley & Emily Norrod
Nearly 66 million years ago, the Earth entered what is now known as the Cenozoic Era. This era is made up of several smaller geologic time periods including the one in which we currently reside: the Quaternary. The Quaternary time period began around 2.6 million years ago and at the beginning of this time period, the Earth’s land masses had mostly settled into their current formations with very little movement since. The most significant part of this time period in terms of geological setting is the cycle of Ice Ages which significantly transformed the Earth’s surface.

At the greatest extent, glaciers covered about 2/3rds of Ohio. As glaciers extended down, they scraped the surface of the Earth, collecting debris and rock as they went. In the reserve, as the glaciers began melting, they left deposits of unsorted sediment in their wake.

Map showing various glacial deposits.
During this time period, Ohio had no plate boundaries’ movement effecting it’s rock formations. Instead, rock formations were changed by the movement of glaciers that covered most of the state.

Glaciers, such as Jackson

The glaciers that covered Ohio slowly receded and left deposits of sediment or "glacial till" in their wake.

The rock that was deposited during the Quaternary period in Ohio came from melting glaciers which filled valleys with sand, clay, silt, gravel, and boulders. These deposits are still commonly found in Ohio to this day, making up much of the upper layers of our rock and dirt.

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