Limestone Bluffs of Eden Valley Refuge

The images from Eden Valley Refuge highlight the exposed limestone outcrops. Limestone is a sedimentary rock and is formed by an accumulation of skeletal fragments of marine organisms. The marine organisms were living in a shallow, tropical sea covering Iowa around 430 million years ago. The fossils present in the images from Eden Valley Refuge consist of brachiopods, corals, and crinoids.

Image

Baldwin

Iowa Core Standard

4-ESS1-1

Identify evidence from patterns in rock formations and fossils in rock layers to support an explanation for changes in a landscape over time

Driving Question

Why are fossils found in limestone bluffs/outcrops in Iowa?

Probing Questions

What is limestone?
What are fossils?
What is the history of Iowa's landscape?

Classroom Suggestions

Students could:

View the Bedrock Geologic Map of Iowa to determine the age of bedrock in different areas of the state.
Research Iowa's geology to understand the landforms and landscapes of Iowa.
Identify fossil species found in Iowa.
Visit a local state or county park, preserve, or recreation area with limestone outcrops and identify fossil species.

Resources

National Resource Conservation Service | Iowa Geological and Water Survey: Bedrock Geological Map of Iowa: This source from the Iowa Geological and Water Survey is a Bedrock Geologic Map of Iowa.
Iowa State University Extension: Landforms and Geology - Iowa's Nature Series: A free PDF booklet detailing Iowa geology, fossils and landforms.
Iowa Geological Survey | Fossils: This source from the Iowa Geological Survey provides photographs and descriptions of fossils found in Iowa.

Contributors

Submitted by Amanda Fowler as part of the Iowa STEM Teacher Externship program.