Have your ever wondered where lakes and rivers came from?
Well, we'll have to travel back a long way back in time to know the answer. Geologist (people who study geology) have learned much about our natural history. We had a "chilly" beginning.
Nature Using Ice to Shape Our World.
Source: Canada & USA Great Lakes. Visit their [Great Lakes Kids] page for some learn fun!. |
Over 2 million years ago our area was covered by ice that came down from the north pole which is at the top of the Earth. This is called an "Ice Age", a period in time when Earth was cooling. The Earth goes through cooling and warming periods about every 150 million years according to geologist.
During the cooling period of an Ice Age, the water freezes and expands the ice caps of the north and south poles. Since most of the Earth is covered with water there is plenty available for forming new ice to expand outward covering new areas of land and water.
Ice has huge strength and is able to move land and shape it into mountains. Imagine playing at the beach and you are the ice. As you walk through the sand you leave foot prints because of your size and weight. As you move your hand through the sand you leave grooves and hills because of your strength. This is how an ice age affects land.
As Earth moves into a warming period, the ice melts and water flows to the lowest areas fill valleys and creating lakes, and expanding the waters that already exist. Left behind a land areas that have been reshaped, new mountains, valleys and bodies of water such as our Saginaw River and Saginaw Bay. The ice age helped to creat the Great Lakes which are around our state of Michigan.
The images on the right shows our area inside the yellow circle and how the last ice age affected our land and water. Below are two color images that show this also.
| Do you know why ice can shape lakes and mountains? |
| If you've ever put a pop can into the freezer and forgot about it you'll understand! When water freezes it increases in size (expands) and this force is so strong it can move anything. |
How The Ice Shaped Michigan and Bay County.
This "Ice Age" image of Michigan shows the area cover with ice (white), water (blue) and land areas (green). Notice how Bay County is covered by ice and much of the area west and south areas of Bay County are covered with water. This water way travels across Michigan connection Lake Huron and Lake Michigan. The big cities of Detroit and Chicago are completely covered by water .
This image shows the water way areas for the counties of Bay, Midland and Saginaw. The black area are the cities of Bay City, Midland and Saginaw, the light blue are existing rivers and the Saginaw Bay, and the slightly darker blue shows areas known as flood basins. We are fortunate that the pioneers that settled these communities did not do so in the flood basins. However, it is possible in very long extended periods of heavy rain can cause more areas along the banks of the river and shoreline along the bay to be flooded. Flooding is also dependent on the overall level of the Great Lakes.
We learned about how ice glaciers long ago shape land, but we also do a lot of things with ice in our everyday life.
| Can you think of some other ways we use ice? |
| I'll mention the easy one -- "ice cubes" to cool off a warm drink. |
Next, we'll talk about some of our FRIENDS in nature!
| Welcome | History? 1-2 | Geography | Nature 1-2 | Discovery | Natives | Settlers | Lumber | Things | The End
Nature 2