I’ve previously posted my frustration with the silence concerning the presumably on-going research to characterize and date this extraordinarily young impact crater in Greenland.
I’ll put that rant aside, and repeat the establishment line here (unchanged since the discovery): The cosmic impact crater creating, climate changing, 5-mile deep, 19-mile wide, bowl of molten rock is somewhere between 3 million and 13,000 years old. [cough]
A notable exception to the silence was the presentation of a poster at 2019 AGU by members of the Hiawatha research team announcing the discovery of a “potential groundwater table” betwixt the jumbled rock and the ice. They quickly follow this statement with a tellingly bolded disclaimer “However, this observation, and characterization of the overlying material, has yet to be determined, by detailed radiometric analysis.”
[Why the bold? Is finding water under the ice at this location in this context anomalous? Is believing it is so…intellectually dangerous? lol]
It stands to reason that a concave cavity of molten rock hell appearing instantly on the landscape ~12,881 years ago might still be emitting enough residual heat to melt glacial ice as it encroaches across the fresh crater. Square miles of “astroclastic” molten rock might cool slowly, in proportion to their mass, over near geological time. And perhaps remain warm enough to melt the overlaying freeze.
Good on the Hiawatha Team for discovering the water and publishing even tentative results. But it would be even more interesting to hear from those same researchers directly, outside the stilted prose and cautious context of “posters” and “papers.”
One of the few bits of direct commentary on the nature of Hiawatha’s globally important subsurface was grizzled ice veteran Dr. Mark Fahnstock’s commentary below (over a year ago of course). I’ll leave it to you all to parse his words yourself, and see if you can intuit whether Mark thinks that the nether world below the ice is a smoking gun for an end-Pleistocene impact.