Graham Hancock on science: what the evidence says · JRE #1284
“there's already evidence of comet impact in Greenland, which goes back to papers published in the Proceedings of the National Academy of Sciences in 2013, that they found what are called impact proxies in Greenland”
What the evidence says
Hancock is referring to the Hiawatha structure, a 31-kilometer-wide (about 19-mile) crater beneath Hiawatha Glacier in northwest Greenland, first reported in 2018 using airborne radar and glaciofluvial sediment containing shocked quartz. At the time of that 2018 announcement and this 2019 podcast episode, the crater's age was unknown and researchers explicitly noted it was undated, leaving open speculation that it could be linked to the Younger Dryas impact hypothesis and the 12,800-year-old impact proxies (nanodiamonds, platinum, carbon spherules) described in the 2013 PNAS-era literature. That link was subsequently tested directly: a 2022 study in Science Advances used two independent radiometric methods, argon-argon dating and uranium-lead dating of shocked zircon from impact melt rock, to date the Hiawatha impact to 57.99 plus or minus 0.54 million years ago, in the Late Paleocene. The study concludes the impact structure far predates Pleistocene glaciation and is unrelated to the roughly 12,800-year-old Younger Dryas period. Current evidence therefore does not support treating the Hiawatha crater as physical confirmation of the Younger Dryas impact hypothesis referenced in the 2013 PNAS-era literature that Hancock cites.