From fossils to geodes, students rock out 2010.02.24

Written by David Green.


Steve Tchozeski picked up a large object from a table and held it up for Morenci second grade students to see. It didn’t take students long to figure out they were looking at an enormous tooth.front.fossils.jpg

“This came from an animal that walked through your playground about 10,000 years ago,” said Mr. Tchozeski, from Great Lakes GeoScience.

It came from a mastodon skeleton that was found not too far from Morenci, he said, and he noted that mastodons covered quite a wide range in their search for food.

It just might have plodded through Morenci at one time.

Next Mr. Tchozeski showed students some common fossils found in Michigan such as coral—a marine organism that lives in clear, shallow, tropical oceans.

What does this tell you about Michigan’s past?

“This tells me that at one time Michigan was covered with a warm, tropical ocean,” Mr. Tchozeski said.

The coral had been imbedded in limestone collected from a quarry near Charlevoix, Mich. It was about 350 million years old.

Mr. Tchozeski told the young science students they would soon be given a small sack of Charlevoix limestone and a special scientific instrument to assist their collection of fossils—a toothbrush.

Anything they found—coral, brachiopods, sponges—they could keep to take home.

Mr. Tchozeski explained that scientists must use their knowledge of plants and animals to work as detectives to learn about the past.steve.tchozeski.jpg

He picked up an enormous footprint embedded in rock—the print of a three-toed dinosaur. A friend of his found a path of the footprints that extended nearly a mile. The raptors walked through mud which, over millions of years, became shale rock.

By comparing the prints to today’s lizards, his friend concluded the animals were walking. A running or jumping dinosaur would have left a much different footprint behind. Small prints were found in the center of the trail, with larger prints on the outside.

“The babies were in the middle and the older dinosaurs were on the outside,” Mr. Tchozeski said. “They were good parents.”

He wrapped up his examples of how scientists read fossils, then gave students their turn to become paleontologists for the day.

• Great Lakes Geoscience offers a variety of geological experiences for school students. In addition to the fossil program for the second grade, fourth grade students were given a quartz crystal dig; kindergarten students looked at geodes; first grade students studied minerals; and third graders learned about volcanoes.
