Tennessee Crater Inches Toward Recognition

tetrahedrassface writes "Slashdot carried the story of an-as-yet unverified impact crater in Tennessee a couple of years ago. After a few weeks of fairly hardcore sample taking, digging, obtaining some good images and manipulating them, I'm proud to report the first batch of evidence in favor of it being an impact site. The primary smoking gun is the presentation of an astrobleme, obtained from High Resolution Ornithographic Images taken in 2008. Also of note are the melted/deformed rocks, magnetic crater dust, and the fitment of the crater rim to a circle. A rented plane and a bunch of photographs today and it's pretty obvious that it's a crater, folks. Cheers!"

For a great crater call: Middlesboro Kentucky

[Penurious Penguin]

Considering the relative proximity to this extremely badass crater [wikipedia.org], I'll consider it.

On a different note; oh how beneath the glorious reign of Reinheitsgebot I'd love to have a corpulent barrel of dunkel in this place [planetoddity.com].

The last link

[93 Escort Wagon]

Looking at the last link - a photo - it's most certainly not "pretty obvious" it's a crater. given the area we're talking about, it could quite easily be the remnants of an old, rather large, sinkhole.

Megabar Shocked Material = Smoking Gun

[crunchygranola]

"A rented plane and a bunch of photographs today and it's pretty obvious that it's a crater, folks."

Only if "crater" means "circular depression". Sinkholes make nice circular depressions also, and are far from rare in the South. And the summary misuses the term "astrobleme" which means "cosmic impact crater" and would be the whole circular structure. I gather the poster is referring to an elevated region in the center which may be an impact rebound peak.

Melted rock and magnetic dust makes the case stronger (but ancient volcanism could account for at least the melted rock), but the real smoking gun that would make the case without any doubt would be coesite or stishovite (for example), quartz that has been transformed by megabar (millions of atmospheres) of pressure. These materials (or other evidence of extremely intense shock waves such as characteristic microfractures) are virtual proof of a cosmic impact.

Age of Crater

[paleo2002]

The crater is in Hamilton County which is along the southern border of the eastern part of the state. Looking at a geologic map of the region, the county is sitting on rocks from somewhere between Cambrian and Ordovician in age (about 540-440Ma). However, the region's geography is dominated by a thrust-and-fold mountain belt that formed during the Alleghenian orogeny about 325-260Ma. The crater is undeformed so it has to post-date the collisional event. Its definitely less than 260Ma. Considering how symmetrical the crater is, its probably a lot younger but I can't find any sedimentary maps for the area.

Or, you could ask a local Tennessee student and s/he will tell you the crater was formed when God smote Satan 10,000 years ago.