Delving Deep For Educators

Delving Deep Movie Poster
Delving Deep: Scientific Discoveries from Iowa's Ancient Sea

Researchers from the Iowa Geological Survey have discovered evidence that a meteorite struck Iowa near the town of Decorah, in Winneshiek County. This event took place during the Ordovician Period, 465 million years ago. The meteorite created a deep crater 3.5 miles in diameter which was flooded by a shallow sea way. Few animals could survive in the brackish, low oxygen environment within the crater. This unique environment resulted in the extraordinary preservation of spectacular fossils, some of which have never been seen before. These fossils are providing researchers with new information about the creatures that lived during the Ordovician Period and their habitats.

Students will see sample meteorites and learn about the Decorah impact crater.

Students will see fossils that come from the Ordovician Period, 485 to 443 million years ago, when Iowa was covered by a shallow tropical sea. The creatures that lived in this sea include crinoids, brachiopods, gastropods, corals, graptolites, and primitive fish.

Thanks to the process of plate tectonics, the land that we call Iowa was situated south of the equator during the Ordovician Period. Earth's climate at that time was mild, the temperatures were warm and the atmosphere contained a lot of moisture.

One of the most spectacular fossils found in the meteorite crater deposits is a giant eurypterid, sometimes called a "sea scorpion". It was 5-6 feet long and was the first really large predator on earth, more than 2 million years before the dinosaurs! Students will see a life-size model of this creature and learn about the physical characteristics that adapted it to survive and thrive in its environment.

There is no surface evidence of the Decorah meteorite crater today. A graphic panel will walk students through the investigations that lead geologists to its discovery, demonstrating how the Scientific Method process works in a real research situation.

Exhibit Partners

The research featured in this exhibit was conducted by the Iowa Geological Survey and the University of Iowa Department of Earth and Environmental Sciences, Paleontology Repository. The exhibit was prepared in collaboration with the Office of the State Archaeologist. The model of the giant eurypterid was created by Dennis Wilson of Pangea Designs and the eurypterid art work is by Patrick Lynch of Yale University.

Extended Activities

Discovery Trunks

The University of Iowa Museum of Natural History, Old Capitol Museum and the Office of the State Archaeologist have created a series of Discovery Trunks that are available for educators. Topics covered in these trunks are especially well suited to complement exhibits in the 2017 Mobile Museum. These trunks are a bonanza of teaching materials that provide hands-on activities and lessons the fit core teaching goals related to geology and culture history. The trunks are designed to develop scientific, cultural, and historical literacy for students of all ages. They are available to educators, homeschool groups, parents working with local AEAs, libraries, nature centers, and others engaged in educational programing. Reserve a Discovery Trunk here!

Suggested Reading

  • Fossils Tell of Long Ago by Aliki. Harper Collins, 1990
  • The Fossil Factory: A Kid’s Guide to Digging Up Dinosaurs, Exploring Evolution, and Finding Fossils by Niles Eldredge, Douglas Eldredge, and Gregory Eldredge. Roberts Rinehart, 2002.
  • How the Earth Works: 60 Fun Activities for Exploring Volcanoes, Fossils, Earthquakes and More by Michelle O’Brien-Palmer. Chicago Press, 2002
  • The Magic School Bus: Inside the Earth by Joanna Cole. Scholastic Books, 1989
  • Investigating Plate Tectonics by Greg Young. Teacher Created Materials, 2007


Old Capitol Museum

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