United States Meteorite Impact Craters

Newly reported. 5.6 km, mostly buried. 460 to 483 million years old. Impact origin supported by indexed PDFs in quartz grains.

French B. M., McKay R. M., Liu H. P., Briggs D. E. G., Witzke B. J. 2018. The Decorah structure, northeastern Iowa: Geology and evidence for formation by meteorite impact.GSA Bulletin, Research Article, https://doi.org/10.1130/B31925.1 

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/545187/The-Decorah-structure-northeastern-Iowa-Geology