Geology in state parks

Lake Superior Agates

Many of Minnesota's fascinating geological features may be seen in its state parks. Old mines and quarries, evidence of volcanoes, glaciers, and ancient seas are just some of the things you will see. What would you be interested in going to see?

Hill Annex Mine State Park (in Calumet, MN)
This park is an old open pit iron ore mine. You can see the Coleraine (CO-la-rain) Formation, a layer of material composed of shale, sandstone and iron ore conglomerates. This formation was created 60 to 105 million years ago when an ancient sea covered the Mesabi Range area. The formation is a good source of fossilized shark's teeth, ocean snails, clams and crocodile parts.

Soudan Underground Mine State Park (Soudan, MN)
Go almost 1/2 mile below the surface to view the world of underground mining. Opened in 1883, the Soudan Mine is Minnesota's oldest and deepest iron ore mine. Ely Greenstone, volcanic rocks and sediments formed in oceans over 2.7 billion years old, may be seen here.

Banning State Park (Sandstone, MN)
This park contains many old sandstone quarries. These quarries were opened in the 1870's to 1880's, when sandstone was a popular building material.

Jay Cooke State Park (Carlton, MN)
The Precambrian Thomson Formation is located within Jay Cooke State Park. The formation is a layer of mud that was compressed and hardened into shale, then compressed further into slate, and finally folded. This formation is about two billion years old.

Moose Lake State Park (Moose Lake, MN)
Learn more about Minnesota's state gemstone, the Lake Superior agate, while visiting this park. The Lake Superior agate is the oldest of the world's agates, 1.1 billion years old. The agate is composed of quartz with distinctive red and white banding.

Interstate State Park (Taylor's Falls, MN)
In this park you can see the effects of glaciers 11,000 years ago. Potholes were created by rivers draining the glacial lake to the north. The basalt rock formation from 1.1 billion years ago confined the river to a gorge, and the river cut through overlying siltstones and sandstones and some of the basalt to create potholes.

Maplewood State Park (Pelican Rapids, MN) and Glacial Lakes State Park (Starbuck, MN)
Glacial action may also be seen at these two state parks. Kames (cone shaped hills) formed when glaciers deposited loads of sand and gravel within a depression of ice. When the ice melted, the deposit became a hill.

Forestville and Mystery Cave State Park (Preston, MN)
Take a cave tour and look at the stalactites (calcite deposits hanging from the cave roof) and stalagmites (calcite deposits rising from the cave floor). You can also see standing pools and flowstone which formed when groundwater saturated with calcium carbonate evaporated within a rock cavity.

Lake Bemidji State Park (Bemidji, MN)
Take a walk on the bog trail and explore the surrounding peatland.

Blue Mounds State Park (Luverne, MN)
From a distance the Sioux quartzite cliff within this park appears to blue. This geological formation is about 1.5 billion years old, and was probably formed in a shallow sea.

State park trail guides provide information about the geological features in the park. You can also ask the park manager to help you locate the geological features. Do some exploring and see Minnesota's geology up close.

Rock collecting is not allowed in the state parks, since the parks preserve the natural resources for everyone to enjoy. However, rocks may often be collected near a park. Fossil hunting tours are available by reservation through the Hill Annex State Park and agate hunting is available in some gravel pits near Moose Lake State Park, if permission of the owners is obtained. Before going on private lands to collect rocks, obtain the permission of the landowner. You may be told that you cannot go on a person's land to collect rocks because the person is concerned about people being injured or property being damaged.

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