School Of Rock | Study Up On The State's Special Features

Molly Meister and Sue Johansen-Mayoleth

Molly Meister is a publications supervisor in the DNR’s Office of Communications. Sue Johansen-Mayoleth is a naturalist at Devil’s Lake State Park.

Many places in Wisconsin have been shaped by moving glaciers, wind, water and other things, making cool-looking rock formations for billions of years. Look for these features on your next outdoor adventure.

Igneous Rocks

Lava under the Earth’s crust can turn into igneous rock when it cools off and hardens. When lava cools beneath the surface, it’s called intrusive igneous rock. To spot this rock, look for large crystals, like you’ll find in granite. When lava cools above the surface, it’s called extrusive igneous rock, like basalt. It will have small crystals because it cools fast.

Red granite, an igneous rock, is Wisconsin’s state rock.

iStock/Fokinol

The official Wisconsin state rock is red granite, an igneous rock named the state rock in 1971. It is abundant in the state, and there’s even a place in central Wisconsin called Redgranite.

Metamorphic Rocks

Deep in the Earth, any rock can become a metamorphic rock from heat, pressure or adding hot liquid with minerals in it. This process doesn’t melt the rocks but turns them into a new rock. Some of them are marble (once limestone), slate (once shale) and quartzite (once sandstone).

Many of the bluffs and rock formations at Devil’s Lake State Park are made of quartzite, a type of metamorphic rock.

Nick Collura/Travel Wisconsin

Sedimentary Rocks

These are made when different materials are layered on top of each other. You might find fossils in this type of rock, which includes sandstone, limestone and shale.

Roche-a-Cri State Park features good examples of sedimentary rock in its colorful sandstone cliffs.

Aaron Carlson

Kettle

This is a shallow hole left behind by a glacier moving backward as it melted. As the glacier moved, a block of ice broke off and got stuck in the ground. When the ice melted, it filled the hole with water, soil and sand, creating a kettle lake or pond.

Kettles, or pits on the landscape, can fill with water and become kettle lakes or ponds, like this one in the Northern Unit of the Kettle Moraine State Forest.

Tim Mulholland/Illuminata Photo

Drumlin

This is a hill shaped like a teardrop that has a smooth surface. While glaciers melted, they took away materials in one spot and put them in another.

Dane County’s Goose Lake Drumlins State Natural Area contains all or part of six drumlins left by Wisconsin’s receding glacier.

Joshua Mayer

Moraine

These also are made from material left behind by moving glaciers. Large ice sheets pushed rock and soil across the landscape like a bulldozer. Some rocks were left on the sides (lateral moraine) and some in front of the ice (terminal moraine). These moraines show us where the glaciers moved.

Moraines like this one along the Ice Age Trail in Cross Plains were formed when glaciers left mounds of debris as they pushed through the area.

iStock/Dave Jonasen

Make Your Own Sediment Layer Bars

Recipe by Paige Hudson

This activity originally appeared in Elemental Science, an online resource for educators, found at elementalscience.com. Paige Hudson is the author of the website’s award-winning science curriculum.

These sediment layer bars are made layer by layer, just like sedimentary rocks.

Ingredients

• ½ cup butter

• 1½ cups graham cracker crumbs

• 1 cup chocolate chips

• 1 cup chopped nuts

• 1 cup peanut butter chips

• 1 (14 oz.) can sweetened condensed milk

Directions

1. Have an adult preheat an oven to 350 degrees and use the heat to melt the butter in a 9-inch-by-13-inch baking pan.

2. Sprinkle graham cracker crumbs over the butter.

3. Next, sprinkle the chocolate chips over the crumbs, followed by the nuts and peanut butter chips.

4. Being careful of the hot pan, press down gently, then pour the condensed milk evenly on top.

5. Bake the cookies for 25-30 minutes at 350 degrees.

Let the cookies cool a bit before cutting them into squares. After they cool completely, you can eat and enjoy your sedimentary rock treats!

Daniel Robinson