On this episode of “Rhymes with Decorah”, we tell the incredible story of geologist Jean Young and the discovery of the Decorah Impact Crater. Long time educator and NE Iowa native Birgitta Meade joins us to tell the story of Jean, who she also called a friend, right up to her passing in 2010. We dedicate this episode to all those who are willing to follow a hunch in life, and take action in their beliefs, no matter what others may say.
Jean Young was indeed, a “character” – a well educated geologist, regarded local artist, and fan of dragons. Jean was also a founding member of the Oneota Coop, served as a board member of Ryumonji Zen Center, and lived a simple, but fascinating life surrounded by rocks! While many locals likely found Jean’s eccentricities and lifestyle a bit out of place in NE Iowa, Jean had many friends and her scientific hunches were something of absolute genius. Jean’s work in discovering the Decorah Crater could very easily have never happened – and we are all the benefactors of it.
Flowers And Falling Hearts, by Jean Young
In 2004-2005 a team including Jean Young, Robert McKay and H Paul Liu from the Iowa Geological Survey helped discover the Decorah Impact Crater – and particularly the ancient layer of shale (The Winneshiek Shale) that would provide some incredible geologic discoveries.
470 million years ago, the eastern edge of what is now Decorah was hit by a 650-foot meteorite. At that time, much of North America, including what is now Iowa, was covered in ancient oceans, and it was sediment from those oceans that filled in the crater basin creating layers of shale.
It was these layers of shale that led to the discovery of the meteor crater by citizen geologist and artist Jean Young. One of Jean’s jobs over the years was studying well-drillings for the state of Iowa to help present information on the most efficient (water) well locations. It was within these samples from around the Decorah area that she started noticing unusual patterns – including shale – which should not have geographically been there in comparison to the surrounding area. After contacting friends and acquaintances at the Iowa Geological Survey Jean’s hunch proved correct – that the shale layer represented an impact crater below the surface of Decorah.
Eventually the Iowa Geological Survey mapped the samples, outlining the crater’s basin. Scientists tested the layer of material underneath the crater for shocked quartz (shattered crystals) and conducted rock density and electromagnetic aerial surveys, confirming the impact structure.
Not only did the shale layer confirm the impact crater, but to everyone’s great surprise, the layer also held incredible fossils – many of which had never been seen before and entirely different from the surrounding geography. The most incredible of these discoveries (so far) is Pentecopterus Decorahensis, a six-foot-long sea scorpion that pre-dated the oldest known sea scorpion by 10,000 years.
Pentecopterus rendering by Patrick Lynch, Yale University
To get at the fossils, inconveniently located underneath the Upper Iowa River, scientists temporarily diverted the river from the excavation site, recovering more than 5,000 specimens, including plants, shrimp-like animals, and the oldest known fossils of jawless fish. These discoveries have led to new insights into what life was like during the Ordovician period, and all because of Jean Young’s hunch.
Birgitta and others are in the early stages of documenting Jean’s work in the discovery of the impact crater, and are already working to share this story and the science behind it with children and adults across the region through presentations and information. The group hopes to have a full website in the future with information, additional discoveries, and more.
You can visit this page for more information on the basics of the Decorah Impact Crater or a more in depth 2015 article from the Iowa Science Interface. We would like to offer a sincere thank you to Birgitta Meade for helping tell the story of Jean Young and this incredible discovery in our region.
