Tennessee Crater Inches Toward Recognition 113
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!"
typo? (Score:5, Informative)
ornithographic or orthographic?
Re:typo? (Score:5, Funny)
Where do you think that meteors come from? It turns out that space is inhabited by giant birds,...
If anyone want to see where this "crater" is... (Score:3)
I'd have to say that it looks nothing like a meteor crater and a lot like a sinkhole caused by an underground collapse. Meteor craters that size would be very round and would cause circular deformation of the surrounding area.
Siderite found in the depression would exactly match what was shown on the website.
You're welcome.
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what's hard to understand about not yet verified?
Bird pics? (Score:5, Informative)
... High Resolution Ornithographic Images ...
As taken by birds? Perhaps you meant orthographic? [wiktionary.org]
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Bird's eye view, perhaps?
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Re:Bird pics? (Score:4, Funny)
Keep a lookout for Kal-El (Score:1)
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Is there something spectacular about this particular dimple in the earth?
Well, yeah! This one hasn't been completely weathered away like most of the others. Sheesh. After all, these things don't tend to stick around all that long, geologically speaking, and it's not like we have an airless moon close by covered with the damned things ... Oh, wait.
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Yeah, it's not like anybody on Slashdot is interested in science or anything.
Still not convinced (Score:2)
evidence is for the birds. (Score:3)
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Oh wow, another ingenious bird pun designed to ruffle the guy's feathers. Bravo.
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Slashdotted (Score:2)
Linking to a server via IP address on Slashdot, huh? Yeah, that's going to hold up.
The primary smoking gun... (Score:1)
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 unusual parts from the alien spacecraft that crashed there .
Fixed that for you.
For a great crater call: Middlesboro Kentucky (Score:4, Interesting)
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 (Score:2, Interesting)
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 (Score:5, Interesting)
"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.
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You can't argue with the rebound ring in da bottom. :0
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You can't argue with the rebound ring in da bottom. :0
That is literally true.
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Not much else in the area with similar depressed topology. Seems if it is/was a sinkhole, there would be more like it there or nearby to be seen.
Dusty, I think it is neat that you are gathering this sort of evidence. Kudos!
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Thanks, and the evidence gathering continues. I understand the bar is high. This was an update on a topic allowed to languish too long. :)
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Nowhere, ever have I stated there is a central peak. Take long look at the GIS map and compare it to the Orthologocal image. Not only do they match but they do in fact show a rebound/shock ring that is unifrom across the floor of the crater/pipe. It's round. Two years ago everyone I. Spoke to told me I was crazy and it was square. Does it look sqaure to you???
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Yep, I went to high school in east Tennessee. We had a big sinkhole open up right in the football field! Hahaha. Too bad they filled it in.
Were you able to exclude karst? (Score:5, Informative)
Possible. But I'd sure want to exclude karst features (e.g., sinkholes) before accepting an impact origin for a topographic feature in a known karst area. Mapped karst features are awfully close to where the "crater" site is.
Also, your shattercones don't look like real shattercones [wikipedia.org], which have a nested, cone-shaped geometry. What you illustrate looks more like an ordinary concoidal fracture [wikipedia.org]. Break a rock by any method and you can get those.
If you want to identify impact melt convincingly, then ordinary macroscopic pictures won't do. You need a thin section [wikipedia.org] and some petrographic microscope work. Sometimes even forest fires can melt rocks on the surface, or a camp fire if it is big enough.
Some terrestrial minerals are highly magnetic, but also quite resistant to weathering, and will get left behind (and even concentrated) while other minerals are altered. For example, magnetite [wikipedia.org]. If it were demonstrated to be metal (i.e. unoxidized), especially if a combination of iron and nickel, that would be suggestive, but you'd still have to exclude man-made contamination.
Missing from your sampling is context. Disconnected rocks removed from their geological context are not as useful as understanding how they were arranged in the field. This is especially true for features like shattercones, which should have a clear geometrical relationship to the crater (i.e. basically a radial arrangement). If you are sampling from rubble on the surface, rather than bedrock, you really don't know what you've got. It could be transported by river, gravity (mass wasting), or (not sure if possible at this location) glaciers. It might not even be local. A lot of your samples have lichens and weathering rinds suggesting that these aren't particularly fresh samples (this is why geologists bring geological hammers and suitable eye protection to use them).
In short, you've got an interesting feature, but you are still far from demonstrating it is a crater.
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Yeah a lot of sinkholes have astroblemes...
Re:Were you able to exclude karst? (Score:5, Informative)
Re:Were you able to exclude karst? (Score:4, Insightful)
I fully intend on getting thin sections done. The gravel IS angular. There are heavily deformed Ordovician Age rocks. Unfortunately, where this area is a Karst area. You can't pick up the feature and move it to an area that makes it easier. Is this a Karst feature? I doubt it very seriously. However thin sections for shocked quartz are next on the list. I appreciate the time you took to reply. No topsoil was never pushed into the middle of this feature. Yes, a road was cut in pushing regolith into one corner and making it look a lot squarer than it is. I know the full history behind the site going back over 120 years. There is rounded material i.e. (sand) in the soil around the crater at a microscopic level because the soil is 200+ million years old and already contained HEAVILY WEATHERED ancient rock..
The investigation continues. Thin samples of severely deformed rocks are next.
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I wouldn't worry too much about the squarish shape. It's close enough that I don't think the shape in map view is an obstacle to it being an impact crater, especially if it has experienced weathering. You mention Barringer Crater [wikipedia.org] which isn't perfectly round either, and that's a fair analogy. However, all the other issues mentioned still stand. There are an awful lot of ways to make a roughly-circular pit in the bedrock geology, especially in a karst area. Generally speaking, if we were on Mars or the M
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I grew up in Middlesboro, Kentucky, and it took quite a few years before it was determined that the valley was actually the remnants of a meteor crater. I remember going past the huge USGS map that hung along one wall of the mall and seeing the obvious circular shape of the valley, especially when the kinds of rocks were identified with different colors, it formed a definite bulls-eye. Most noticable was the description of "shocked quartz" in the valley rocks, and the small raised area in the center of the
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You keep using that word... it does not mean what you think it does.
Makes perfect sense (Score:4, Funny)
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Which is riding on the back of a gigantic turtle.
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Stupid slashdot filter. I wanted to make a funny response, for those of us who know an love Pratchett, but no, I have to type a bunch of stuff not caps to evade the filter. Grrrrrrrr.
Age of Crater (Score:2, Interesting)
Shocked quartz (Score:3)
The smoking gun will be shocked quartz.
Re:Gee, amateur science (Score:5, Insightful)
I'm a professional scientist with a pile of published papers, and I'm here to say that amateur science is a very good thing. Who are we to tell young Calvin to turn off his inquisitive mind when he hits puberty? The guy who wrote TFA is a *far* more interesting person than the people who're mocking him.
Now, do I believe that he's right, and this *is* a crater? Nope. I suspect it's wishful thinking. Does his work meet the standards of peer-reviewed scientific literature? Definitely not. Does his work meet the standards of Slashdot? I dunno, does Slashdot have standards? All I can say is I'd rather read articles like this than the Apple flame wars or hackneyed political debates that fill the rest of the news feed.
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As a scientist I will *NOT* fault enthusiasm and simply trying to figure something out. Does he have a convincing scientific case? No. But I have no problem with people trying to learn. Geology can be a difficult subject to get into because there is so much background information to learn. However, it's one of the sciences where you don't necessarily need plenty of expensive lab equipment to figure something out. A lot of geology you can do just by being observant in the field and taking good notes an
Impact crater? Evidence? (Score:5, Informative)
Sorry, I'm not seeing it. Everything I see posted here can be adequately explained without the presence of an impact. Sinkholes are also often round. Magnetic material can accumulate in and weather out of most rock types, and can be introduced through secondary contamination. Vugs are, and other holes/porosity often are, the result of dissolution and weathering (coincidentally, the same processes form sinkholes under the right conditions).
To convince me, do several things:
1. Cut open the weird looking metal pieces and acid-etch them to reveal any Widmanstätten patterns. (Note: the metal in meteors will not react quickly to water or other weak acids, but limestone will. Iron minerals commonly occur in most rock types, not least of all sedimentary rocks, including limestone, that are likely to form sinkholes. Magnetic minerals are actually pretty common. I'd be a little surprised not to find small grains of magnetic material pretty much anywhere on Earth.)
2. Take the rocks to an expert and get an opinion. This often annoys most geologists a little bit since, as one recounted to me, he's had hundreds of people bring him "meteorites" over the years and precisely zero of them were actual meteorites. But if you can get an appropriately trained geologist to glance at them it should be moderately easy to see that they are or are not meteorites, or represent a rock that has melted. If that person can't say definitively, he/she may be sufficiently intrigued to investigate further.
3. If the rocks look interesting to the geologist, running through an electron microprobe and electron microscope will reveal many more interesting things about their precise chemical composition and microscopic structure, as will thin sections under an optical microscope. For the metallic parts reflected light microscopy will tell a great deal. The presence of certain high pressure SiO2 polymorphs is diagnostic in rocks from the impact zone, and iron/nickel composition is a very good indicator in a suspected meteorite.
4. Careful mapping will help, as will a geologic map of the area. Geologic mapping is not difficult, but defensible results require practice and a thorough understanding of geologic principles. Look for the character of the ground, the distribution and size of different material both vertically and laterally, its composition, texture, the nature of contacts between areas with different materials, and the orientation of any different layers, amongst any other notable characteristics. Relate your findings to those on existing geologic maps. Create your map on top of a high resolution topo map.
5. Consider multiple working hypotheses, and keep an open mind. For example, the two obvious hypotheses are that this feature represents a sinkhole or that it instead represents an impact crater. Find as much evidence as you can that contradicts or informs both of those ideas; consider all evidence in light of them. For example, you might observe that the area is characterized by shallow crystalline silicate metamorphic bedrock that is not subject to dissolution, thus pointing away from a sinkhole origin. On the other hand, you might note there are caves in the area, topographic maps show creeks and stream ending abruptly, that there was cement production there in the late 1800s, limestone clasts show traces of pyrite, and there's little evidence of breccia.
It's a logical fallacy to conclude an unusual process must be responsible for an observed feature when your evidence can be adequately explained by more pedestrian processes. Make sure you have solid evidence that can't be explained by more mundane processes before jumping to a novel conclusion -- ad hoc conclusions are inimical to real understanding and the process of science. If an impact is still a reasonable explanation after carefully considering your evidence in light of other hypotheses, systematically write up your findings. Start by giving an overview of the general area, then the feature itself, then the details of specific observations you've made a
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It's a logical fallacy to conclude an unusual process must be responsible for an observed feature when your evidence can be adequately explained by more pedestrian processes.
Exactly why I think the simple solution to this is that he found a sinkhole that was impacted by a meteor.
Hey! (Score:2)
That's where Uncle Jeb's moonshine still blew up in 1925!
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Too bad the recipe was lost with it.
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By they way.. it's been in my family for 40 years, and the family before that for 50 years... And no one has dumped trash and burned stuff..It's been logged twice.
The first had a steam sawmill and cut the virgin timber around 1901. The second time was after a tornado and it was logged/chipped and then planted in pine trees. I know sinkholes. This is no sinkhole, and the evidence above is a great first/second step in bearing that out.
This is a crater and I'm gonna nail it even if it occurs in East Tennes
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Cool. Better yet when in the area one day, ping me. :)
Can someone go check my impact crater candidates? (Score:2)
Can someone please check my impact crater candidates? Maybe they have already been determined.
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Number 1 is Hicks Dome, a structural dome related to igneous processes.
Number 2 looks like erosion at the interface between different geologic layers, probable a ridge of Monongahela Group sandstone and softer Conemaugh Group shale and siltstone. There's nothing about it besides a little bit of roundness that's very crater-like. If this structure has a name I don't know what it is. The fact that it appears to be at the intersection of topography that's very steeply eroded to the west and more subtly incised
where (Score:1)
Flaky evidence at best (Score:2)
First:
1) as others here remark too, a circular feature does not equal an impact crater. Karst depressions are circular too and a strong candidate in this area;
2) magnetic particles can be found in any soil. They do not point to impact as such. Show us geochemical tests that show they are of meteoritic composition, and show us that they have an abundance well over the natural accretion rate
Acid Test Says Not Carbonate.. (Score:2)
I've tested these with acid. If the sample won't react with boiling acid (nitric or sulfuric) why would it stand to reason they are carbonates reacting to rainwater?
P.S. (Score:2)
They don't react with boiling hydrochloric either..
Sample + boiling HCL (Score:2)
Picture of sample here: here. [twitpic.com]
No rxn. That rock looks normal too.... shure... anything but heated and pressed.. amirite?
Here's the site in question (Score:2)
http://goo.gl/maps/jgJyJ [goo.gl]
Note that the photo with the houses at the very top would be taken from the eastern edge of the map with those houses being along Pierce Road pretty much straight over from the bottom "-" of Google Maps' magnifier tool. From the ariel view it could be a sinkhole or a crater, with sinkhole being more common in the area. Someone mentioned below that there is a disappearing stream just a mile from there. That part of Tennessee has some magnificent caves.
Anyway, I hope the poster will
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Thanks, and that's it exactly. Honestly, the rocks are way too deformed for it not to either be an impact crater, or... pehaps.. a Kimberlite tube of large proportions... but, it could be a monster cave, in which case that's cool too. I'm in this for the science, not trying to internet famous or a impact crater finder.You can bet I'm going to keep on it. It's fun.... and it's interesting.
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He's not proud of the crater, he's proud of all the work he's done to verify that it's a crater. Learn to think before writing and the quality of your post will increase dramatically.
Re:Pride?? (Score:5, Funny)
It happened a long time ago. No one had anything to do with it.
It's in Tennessee, God put it there.
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The ironic part of this statement, is that this crater is within just a few miles of the Dayton TN - where the scopes trial took place!
Anyway, it's pretty a pretty cool find, I guess. And considering that the appalachian mountain range is the oldest exposed range on earth, it wouldn't surprise me to find many such ancient events, if we were to look close enough.
This area of the world is actually pretty interesting in regards to human history, fauna, indian history and geologic history. We would be wise no
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So if a meteor took out Nashville and its five major universities, the IQ of the state would double? Yeah, that math works out. Proving your own point?
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No, but most other people on this site are Americans, and it's not much better (and sometimes worse) in most other states in the country.
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I went to middle and high schools in TN, and 2 years of college (on the east side though, in Knoxville). Now I live in Arizona. I think you're mistaken about which state is the retard capital of the USA. Actually, they may be neck-and-neck, having lived in both, it's hard to pick one as a clear winner.
Also, the Creationist Museum is located in Kentucky....
I also spent some time in Mississippi living with a relative over the summer in high school. I think that state may have all the above beat.
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The Smoky Mountains National Park is actually a very nice place. I also hear Chattanooga is a cool city with good tech (for its size). Memphis has an undeniable musical legacy, though these days it's probably not a great place to be. The weather's pretty decent; doesn't get too cold or too hot. It's not a perfect state, but it has its plusses. And, it's better than Mississippi.
Re:Pride?? (Score:5, Insightful)