Think Like a Geologist

Geology | FIND Iowa
Feb 25, 2024 | 01:25

What land forms can be found in Iowa and what do they tell us about history?

Learn about Iowa's geology and ancient past by exploring land features and fossilized creatures.


(Abby Brown, host of FIND Iowa, is standing on some rock outcroppings at Fossil and Prairie Park Preserve in northeastern Iowa. She is wearing a short sleeved light blue Iowa PBS shirt and black pants.)

[Abby Brown] Iowa is such a special place with so many unique, geological sites to visit and learn from.


(The staircase opening going down into the Maquoketa Caves at Maquoketa State Park.)

(Tallgrass land prairie)

(The Maquoketa Caves at Maquoketa Caves State Park)

(The rolling hills of the Loess Hills at the Loess Hills State Forest)

[Abby] But long before people lived in Iowa and before Iowa even had a name, the land here was very different.

(Informational sign)

(Iowa Was Once an Ocean. Iowa and farmland - - yes! But Iowa and oceans- - ? Yes. Iowa spent more than half of the last 600 million years at the bottom of an ocean. Geologists look at clues in bedrock and fossils to figure out when and how the climate and landscape change. Layers of bedrock, each with different fossils, suggest several oceans, one after another, with many periods of dry land in between. Our park’s fossils are dated to an ocean that was here 375 million years ago. The abundance of marine fossils deposited here suggest warm, shallow saltwater and a tropical climate.)

[Abby] Since nobody was here to actually see what it was like or take pictures or write anything down, we study clues in the land as it is today to figure it out. That's how geologists think. And, you can think like a geologist too. Is the land in your town flat?

(An open green field.)

[Abby] Are there hills,

(A group of students walking up a grassy hillside.)

[Abby] or cliffs,

(Man and woman standing at a cliff overlooking a road with a river in the distance.)

[Abby] or fossils?

(A person holding a small crinoid fossil)

[Abby] What about water? Like lakes, or ponds, or rivers.

(A lake with bright purple trees growing on its banks.)

[Abby]What kinds of plants grow in your town?

(A sea of yellow black-eyed Susans.)

[Abby]What color of rocks can you find?

(A tan, gray and brown marbled colored rock wall glistening in the sun.)

[Abby]Now start asking those same questions as you have fun investigating new discoveries in Iowa.

(A young girl leads a group of people through a tallgrass prairie holding a black butterfly net on a metal pole.)

[Announcer] Funding for FIND Iowa has been provided by the following supporters.

(text on screen FIND Iowa, Pella, Gilchrist Foundation)

(text on screen Iowa PBS Education)