Sediment collected from beneath Hiawatha Glacier contained shocked quartz, quartz grains with brown 'toasting,' and minerals altered by shock metamorphism into glass.
Notes on verification
Confirmed by the original peer-reviewed Science Advances study and multiple independent secondary sources, including the research team's own site and science news outlets. All specific mineralogical details match.
Sources
- City-size impact crater found under Greenland ice (nationalgeographic.com)
- https://www.science.org/doi/10.1126/sciadv.aar8173 (science.org)
- https://www.sci.news/othersciences/geoscience/hiawatha-impact-crater-greenland-06610.html (sci.news)
- https://craterexplorer.ca/hiawatha-impact-crater/ (craterexplorer.ca)