Great Lakes Were Never Salty But Michigan Was Part of a Saltwater Sea

The Great Lakes have never been salty, but did you know part of Michigan was once covered by a shallow sea?

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The Great Lakes Unsalted

As long as I have known the Great Lakes have always been unsalted but there is a lot of salt located in parts of the Mitten state.

Detroit is built over one of the biggest salt mines in the world. There are a lot of salt deposits all over Michigan but where did all this salt come from?

Where Did All of Michigan's Rock Salt Come From?

Scientists say millions of years ago, Michigan's Lower Peninsula was once covered by a shallow sea. When the sea dried up the salt deposits were stored in the ground.

Over time, Mother Earth's ground water would carry the salt to the surface forming salt springs or salt flats. Humans and animals have been able to access the salt in Michigan for millions of years.

Just like animals on farms need salt, deer, and elk need salt, and so did the dinosaurs that roamed across Michigan millions of years ago.

What is the Middle Devonian Period?

Drew Sonderegger posted the graphic above on the Michigan Rockhounds Facebook page that's from the Middle Devonian Period when a shallow sea covered parts of Michigan, Illinois, Iowa, and the Appalachian Mountains. It's pretty crazy to think about if you are like me and learning about this for the very first time.

According to palaeos.com, the Middle Devonian Period happened nearly 400 million years ago when the shallow seas covered parts of the United States like Michigan, and left a lot of salt behind. This means the Great Lakes are not as old as people may think they are and why prehistoric sea creature fossils can be found from time to time.

So now we know where all the salt comes from in Michigan and why the Great Lakes are now salt-free.