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Tennessee Crater Inches Toward Recognition

Soulskill posted about a year and a half ago | from the denting-our-planet dept.

Space 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!"

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113 comments

That's no moon... (-1)

Anonymous Coward | about a year and a half ago | (#41158843)

It's a space station!

typo? (5, Informative)

memnock (466995) | about a year and a half ago | (#41158893)

ornithographic or orthographic?

Re:typo? (5, Funny)

fm6 (162816) | about a year and a half ago | (#41160131)

Where do you think that meteors come from? It turns out that space is inhabited by giant birds,...

Re:typo? (0)

Anonymous Coward | about a year and a half ago | (#41166041)

Angry birds am I rite? ..../ducks

Re:typo? (0)

Anonymous Coward | about a year and a half ago | (#41166567)

Where do you think that meteors come from? It turns out that space is inhabited by giant birds,...

Duh, Didn't you play angry birds space... Must have been one hell of a pig infestation in TN!

Re:typo? (0)

Anonymous Coward | about a year and a half ago | (#41160375)

orthn o what?

If anyone want to see where this "crater" is... (2)

DiamondGeezer (872237) | about a year and a half ago | (#41163875)

..it's at this link http://goo.gl/maps/Oe78J [goo.gl]

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.

Bird pics? (5, Informative)

tqk (413719) | about a year and a half ago | (#41158923)

... High Resolution Ornithographic Images ...

As taken by birds? Perhaps you meant orthographic? [wiktionary.org]

Re:Bird pics? (0)

Anonymous Coward | about a year and a half ago | (#41160179)

No, it even says ornithographic in his picture [googleusercontent.com] . Clearly, ornitho (bird) + pornographic = ornithographic = bird porn. Probably shots of Okinawa Woodpeckers [wikipedia.org] and Fluffy-backed Tit-Babblers [wikipedia.org] , and the occasional Brown Booby [wikipedia.org] . Oh, the jokes are endless. Dammit now that I started it I can't make it stop....

Keep a lookout for Kal-El (1)

JimProuty (1298167) | about a year and a half ago | (#41158943)

He's gotta be around there somewhere...

Re:Keep a lookout for Kal-El (0)

Anonymous Coward | about a year and a half ago | (#41160113)

Guerilla Marketing for the upcoming Superman movie???

5ryn

Newsworthy? (-1, Offtopic)

twotacocombo (1529393) | about a year and a half ago | (#41159071)

At some point, a piece of rock fell from the sky and landed in what is now called Tennessee. Is there something spectacular about this particular dimple in the earth?

Re:Newsworthy? (-1)

Anonymous Coward | about a year and a half ago | (#41159135)

At some point, a piece of rock fell from the sky and landed in what is now called Tennessee. Is there something spectacular about this particular dimple in the earth?

there are not many niggers in Tennessee. since they have more white people more discoveries are made. niggers are too busy shooting each other to do shit like this. they are uncivilized apes who should have been left in the jungle you know.

if you think that is offensive or wrong to say, ok then. i got a challenge for you. go into any inner-city ghetto and find out how happy they are to see you. if you make it out alive you will find out they are violent and hateful no matter how not-racist you are. if you don't make it out alive we call that darwinism.

of course none of the liberals and brainwashed masses who get offended and mod this down are going to try that. they know what would happen. but the culture says you aren't supposed to notice that and definitely are never supposed to say it. so they fall in line, dutifully, just like the media told them to.

Re:Newsworthy? (-1)

Anonymous Coward | about a year and a half ago | (#41159309)

I have met niggers with all different colors of skin, and worked in "the ghetto" for quite a few years without incident, maybe cause I wasnt walking around shoutting nigger!

+ you have never been to Memphis have you?

Re:Newsworthy? (2)

tqk (413719) | about a year and a half ago | (#41159197)

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.

Re:Newsworthy? (2)

fm6 (162816) | about a year and a half ago | (#41160115)

Yeah, it's not like anybody on Slashdot is interested in science or anything.

Pride?? (-1, Troll)

JohnWiney (656829) | about a year and a half ago | (#41159129)

Why in the world would one be "proud" of a crater? It is a fact (maybe). It happened a long time ago. No one had anything to do with it. What is there to be "proud" of??

Re:Pride?? (3, Insightful)

Anonymous Coward | about a year and a half ago | (#41159201)

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?? (0)

Anonymous Coward | about a year and a half ago | (#41166143)

Yeah, and if it wasn't just a big sinkhole, I'm sure his pride would be well placed. As it stands however... Well, he should be proud of all the work he did, but he should be less proud that he from evidence that clearly points to "no" still drew whatever conclusion he wanted rather than what the evidence pointed to.

Re:Pride?? (5, Funny)

cob666 (656740) | about a year and a half ago | (#41159263)

It happened a long time ago. No one had anything to do with it.

It's in Tennessee, God put it there.

Re:Pride?? (1)

Anonymous Coward | about a year and a half ago | (#41159605)

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 not to spoil it too much more. I have a US Dept of Interior Survey from the early 1900's with b/w pictures displaying the complete deforestation of most of it. Much of what we see is replanted from the last 100 years.

I will say, aside from this guys personal relationship to the event, how is this significant? If I remember correctly, someone has postulated that the entire city of Nashville TN is within a large impact crater...

Re:Pride?? (0)

Anonymous Coward | about a year and a half ago | (#41159719)

someone has postulated that the entire city of Nashville TN is within a large impact crater...

I would call that premature cratering.

I agree. (-1, Troll)

Grog6 (85859) | about a year and a half ago | (#41160605)

I live in TN; retard capital of the world.

If a meteor took out Nashville, the IQ of the state would double.

If it took out Memphis, the same thing could happen.

All the smart people are in enclaves, close to universities; most are from elsewhere, often overseas.

It's a sad world we live in...

Re:I agree. (1)

Anonymous Coward | about a year and a half ago | (#41160895)

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?

Re:I agree. (0)

Anonymous Coward | about a year and a half ago | (#41162045)

I live in TN; retard capital of the world.

If a meteor took out Nashville, the IQ of the state would double.

If it took out Memphis, the same thing could happen.

Maybe so, but that would have to be one smart meteor.

All the smart people are in enclaves, close to universities; most are from elsewhere, often overseas.

It's a sad world we live in...

Correction- it's a sad world you live in. Most of us don't live in TN.

Re:I agree. (1)

Grishnakh (216268) | about a year and a half ago | (#41162219)

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.

Re:I agree. (1)

Grishnakh (216268) | about a year and a half ago | (#41162209)

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.

Re:I agree. (0)

Anonymous Coward | about a year and a half ago | (#41164799)

Cool sig bro, maybe there's a corollary?
All that's needed for Ignorance to succeed is for intelligent men to do nothing (or whine about it while doing nothing)

Re:Pride?? (0)

interkin3tic (1469267) | about a year and a half ago | (#41160593)

Alternatively: It's Tennessee, what else is there to be proud of there?

Re:Pride?? (1)

Grishnakh (216268) | about a year and a half ago | (#41162241)

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?? (0)

Anonymous Coward | about a year and a half ago | (#41164115)

For every stupid racist redneck in this state there is an equally amazing natural beauty. There's the Smoky Mountains, there's the parks, there's Nashville, a music capital from back when music sucked just a little less (regardless of your opinion on Country music, and personally I don't really like it, but I know what's what). There are forests, mountains, lakes, Native American culture, family histories from the early days of this country. Tennessee isn't the problem with Tennessee, there's much to be proud of here. The problem with Tennessee is the aforementioned bigoted, racist, fundie wingnut rendecks.

Re:Pride?? (4, Insightful)

mmcxii (1707574) | about a year and a half ago | (#41159287)

Makes more sense than being proud of a sporting team, when it comes right down to it. Using your talents to "discover" such a wonder is a fantastic thing.

Re:Pride?? (0)

Anonymous Coward | about a year and a half ago | (#41159625)

That particular expression makes me think of this http://en.wikipedia.org/wiki/More_Crap. Lots of "proud" people there too.

Re:Pride?? (0)

Anonymous Coward | about a year and a half ago | (#41160655)

And exactly what have you done to be proud of, neckbeard?

Still not convinced (1)

Grayhand (2610049) | about a year and a half ago | (#41159183)

They fact they found a pair of boots next to a jug by the crater leads me to believe some ones still blow up on them.

Re:Still not convinced (0)

Anonymous Coward | about a year and a half ago | (#41166509)

Test

The primary smoking gun... (1)

Anonymous Coward | about a year and a half ago | (#41159513)

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 (3, Interesting)

Penurious Penguin (2687307) | about a year and a half ago | (#41159663)

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 (1, Interesting)

93 Escort Wagon (326346) | about a year and a half ago | (#41159797)

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.

Not obvious from a picture alone (0)

Anonymous Coward | about a year and a half ago | (#41161937)

fucking moron

Megabar Shocked Material = Smoking Gun (4, Interesting)

crunchygranola (1954152) | about a year and a half ago | (#41159869)

"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.

Re:Megabar Shocked Material = Smoking Gun (0)

Anonymous Coward | about a year and a half ago | (#41160003)

are virtual proof of a cosmic impact.

Virtual, as opposed to physical proof? So, it's only proof if you put it into binary?

Re:Megabar Shocked Material = Smoking Gun (2)

tetrahedrassface (675645) | about a year and a half ago | (#41160043)

You can't argue with the rebound ring in da bottom. :0

Re:Megabar Shocked Material = Smoking Gun (2)

Jodka (520060) | about a year and a half ago | (#41160301)

You can't argue with the rebound ring in da bottom. :0

That is literally true.

Re:Megabar Shocked Material = Smoking Gun (2)

capnkr (1153623) | about a year and a half ago | (#41161613)

Here's a .kmz of the crater, take a look around: http://minus.com/lbuIRyUOrBNfXR [minus.com]

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! :)

Re:Megabar Shocked Material = Smoking Gun (1)

tetrahedrassface (675645) | about a year and a half ago | (#41163591)

Thanks, and the evidence gathering continues. I understand the bar is high. This was an update on a topic allowed to languish too long. :)

Re:Megabar Shocked Material = Smoking Gun (0)

Anonymous Coward | about a year and a half ago | (#41164007)

Here's a .kmz of the crater, take a look around: http://minus.com/lbuIRyUOrBNfXR [minus.com]

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! :)

Bad science - lack of evidence (ie no other sinkholes in the area) is not evidence of anything.

Re:Megabar Shocked Material = Smoking Gun (0)

Anonymous Coward | about a year and a half ago | (#41164143)

Central peaks aren't usually expected for small craters, like this one would be (~400m diameter or so). They are typical of larger, complex craters [wikipedia.org] , several kilometres in size.

Re:Megabar Shocked Material = Smoking Gun (1)

tetrahedrassface (675645) | about a year and a half ago | (#41165271)

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???

Re:Megabar Shocked Material = Smoking Gun (1)

Grishnakh (216268) | about a year and a half ago | (#41162255)

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? (5, Informative)

Anonymous Coward | about a year and a half ago | (#41160149)

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.

Re:Were you able to exclude karst? (2)

tetrahedrassface (675645) | about a year and a half ago | (#41160213)

Yeah a lot of sinkholes have astroblemes...

Re:Were you able to exclude karst? (0)

Anonymous Coward | about a year and a half ago | (#41160689)

Do you know what the word "astrobleme" means? It's an archaic synonym for impact crater, although it tended to be applied historically to the really large and deeply eroded ones where people were not sure whether volcanic or other terrestrial processes might be possible (e.g., Sudbury [wikipedia.org] or Vredefort [wikipedia.org] ). It was used mostly pre-1970s, and is almost abandoned now, although it is still technically a valid term.

So, a lot of sinkholes have impacts? I don't get it. It's not a sinkhole because it's an impact crater?

"Round thing" does not make a geological structure an impact or an astrobleme. There are other ways to do it, such as a volcanic pipe [wikipedia.org] , diapir [wikipedia.org] , differential weathering of a structural dome [wikipedia.org] or basin, etc.

Re:Were you able to exclude karst? (5, Informative)

Anonymous Coward | about a year and a half ago | (#41161257)

I am a geologist, a quick look at the 24k topographic map for the quadrangle this circular depression is found in shows that there are dozens of karst features in the area (sinkholes). There is even a disappearing stream (classic feature of karst terrain) that occurs ~1.8 km southeast of the questioned feature. I could give location information for some of these karst features if Tennessee was mapped using the Public Land Survey System, but it is not (no section numbers). Given the fact that the area in question is mapped as heavily weathered Ordovician/Cambrian dolomite, and that there are dozens of other karst features, it is very likely that this is a huge sinkhole. I agree with what AC that posted above, your shattercones do not look like real shatter cones, they look like concoidal fractures. Also an impact event will leave a set of radial fractures in the bedrock that could be easily mapped on a rose diagram. In order to conclusively prove impact melt, thin sections will absolutely be required as AC above states. The only way to look at shocked quartz grains, if present, is via thin sections and a polarizing light microscope. You also mentioned that topsoil was pushed into the middle of this feature after logging was completed, because the material at the bottom of the pit is from outside, you would need to dig a trench through the foreign material to get to material that is actually from inside the depression. Surface samples are not enough, the rocks you found could have been weathered rock pushed in with the soil. I suspect that if trenching is done, breakdown blocks from the roof of the collapsed cave below would be found. The gravel you note in your evidence of ejecta, would have to angular and composed of heavily altered rock found within the pit, if the gravel is rounded at all it was transported by water, not a blast.

Re:Were you able to exclude karst? (3, Insightful)

tetrahedrassface (675645) | about a year and a half ago | (#41163597)

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.

Re:Were you able to exclude karst? (2, Insightful)

Anonymous Coward | about a year and a half ago | (#41163989)

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 Moon a crater interpretation for a roundish structure is probably the default, and other possibilities get considered only after excluding a crater interpretation. But on Earth, impact craters are rare because there are so many other processes going on. You pretty much have to exclude all those other processes first, or find something definitive such as the high-pressure phases of quartz (e.g., stishovite [wikipedia.org] ), impact melt [wikipedia.org] (more to it than just "melted rocks"), shocked quartz (although there are other ways to make it), etc. Even then the case can be hard to build up.

If you want an example of just how hard making the case for an impact can be, even when you've got a structure that's "obviously round like a crater", check out the history of Upheaval Dome [wikipedia.org] in Utah. The arguments over that structure date back many decades, and it is especially tricky because a salt diapir interpretation is quite plausible (there are salt deposits in the area). I've seen the structure myself. Even standing on the edge of it, I wasn't convinced it was a crater. But apparently it is, albeit a deeply-eroded one (we're sort of looking at the deep structural deformation beneath the crater rather than the original bowl-shaped depression).

Keep at it, but be aware that you're going to have to expand your understanding of regular geological features too. If you are unfamiliar with what's "normal", geologically-speaking, it's pretty hard to tell what's "anomalous". It might be helpful to go some distance away from the proposed crater and sample some of the same Ordovician target rocks that you are confident are outside the area expected to be affected by the possible crater -- i.e. calibrate your interpretations with something that isn't impact-related. Then you can compare.

Re:Were you able to exclude karst? (0)

Anonymous Coward | about a year and a half ago | (#41165055)

I got 99 astroblemes and this ain't one.

Makes perfect sense (3, Funny)

wbr1 (2538558) | about a year and a half ago | (#41160259)

Of course it is inching. It is, after all, riding on a tectonic plate!

Age of Crater (1, Interesting)

paleo2002 (1079697) | about a year and a half ago | (#41160271)

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.

Gee, amateur science (-1, Troll)

kobotronic (240246) | about a year and a half ago | (#41160319)

So, if young Calvin digs in the back yard and finds a discarded coke bottle and calls it a dinosaur skull we think it's cute because he's just a kid.

When a grownup nerd without any apparent field experience or scientific training gets into pretend-science and goes out in the woods collecting "evidence" to support a fanciful idea about a particular sink hole being a SPACE CRATER - then it goes on slashdot because it's content.

FFS

Re:Gee, amateur science (4, Insightful)

goodmanj (234846) | about a year and a half ago | (#41160777)

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.

Re:Gee, amateur science (0)

Anonymous Coward | about a year and a half ago | (#41161419)

"The Bible Says..." God punched Satan in the face and that thar impact crater is where he landed, in the time of fire breathing dragon demons n stuff. Must've been one epic battle hallelujah!

Re:Gee, amateur science (1)

DMUTPeregrine (612791) | about a year and a half ago | (#41163015)

The highest rated comments criticizing the work give tips on how to do the work properly, so that if it IS a crater and not a sinkhole that can be demonstrated, instead of just guessed at.

Re:Gee, amateur science (1)

Anonymous Coward | about a year and a half ago | (#41164061)

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 and photographs as you map structures across an area. For an impact crater, well, unfortunately the best techniques still need a thin section, a petrographic microscope, and a whole lot of training to interpret thin sections, but even so this is well within the range that a non-expert can achieve if they put the effort into it. And who knows? Maybe he will discover something interesting.

But faulting someone for trying? That's just mean. Next I suppose you'll ridicule someone who knows little about computers for trying to install a Linux distribution on their PC. They have to start somewhere.

Think of this as geological "hacking". It's still at a pretty simple stage, but Slashdot is as good a place as any to talk about it.

Impact crater? Evidence? (5, Informative)

Anonymous Coward | about a year and a half ago | (#41160591)

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 about the feature, its composition, structure, etc. Keep in mind that very few observations speak for themselves, so be sure to explain what you see in each picture and feature, as well as the technique you used and why you used it to process each sample and image in the way you did. Make sure there's some theoretical basis for doing so and that you did so correctly. Only after discussing the characteristics of what you've observed (the "what"), go on to interpret them (the "how"); explain at that point why these features suggest an impact and how you're led to believe they shouldn't be attributed to other processes. After doing all that it'll be a lot easier to convince other people that your conclusion is correct.

Re:Impact crater? Evidence? (0)

Anonymous Coward | about a year and a half ago | (#41165767)

And remember this is tennessee,this is the US, where GWB became president, so where does one find a rock hound "geogligis"t for free, or willing to take the samples and do the work for a miniminal price for an amature?
Excuse al the spelling, I'm just pissed at the attitude listed above. He didn't say, local geology club, or hey this kind of group will be able to help you. But made the process discouraging to the local public. An self aggrandizing asshat.
What you said is correct, but remember, you may be talking to some-one human, with limited resources, not grants from a big pocket. Who has an interest in a science or vocation, who may be learning the ropes of the critical thinking that is needed. Guide them, teach them, encourage them, expand them. don't bombast them, dont critique them without assistance to open them up.

Decide for yourself... (0)

Anonymous Coward | about a year and a half ago | (#41161241)

Feature is at Lat 3518'53.39"N and Lon 8458'57.22"W

Geology/bedrock info can be found at http://mrdata.usgs.gov/geology/state/state.php?state=TN [usgs.gov]

The bedrock at that spot is a dolostone, i.e. a carbonate rock that does dissolves and form karst features (like caves, sinkholes, etc.). Description is at http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=TNOCAk;10 [usgs.gov]

There are plenty of ponds and closed depressions in the same area if you surf around on Google Earth. My guess is it is not an impact crater.

How to explain the metal, "impacted rock", etc.? People are always burning stuff so it is probably melted metal and slag. Some historical research might be helpful--I can imagine people have been dumping junk and trash there for a long time. What else do you do with a hole in the ground...

Re:Decide for yourself... (0)

Anonymous Coward | about a year and a half ago | (#41161331)

By the way, this is definitely known karst terrain. Occam's Razor says K.I.S.S. so to guess the feature is an impact crater vs. a karst feature in a known karst terrain, well, that's up to you to decide.

All this said, I agree with goodmanj above--much more interesting than an Apple world domination post!

Re:Decide for yourself... (1)

tetrahedrassface (675645) | about a year and a half ago | (#41163735)

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 Tennessee. Is there a law saying that meteorites don't hit limestone? Hardly.

Re:Decide for yourself... (0)

Anonymous Coward | about a year and a half ago | (#41167991)

I'm certainly not faulting you for trying to make your case, or for a lack of enthusiasm. Also, I admit that you have been on the ground there, and I have not. That said, I am a trained geologist, and based on all the evidence you have provided so far (which is pretty much just images), well, I think you still have a long way to go to prove this is an impact crater. From my point of observation as a third person given the evidence you have provided, I believe it much more likely to be a karst collapse feature like a sinkhole. But I have an open mind--I observe, and draw my conclusions based on hard evidence. If you can provide the extraordinary evidence needed to back up your extraordinary claim vs. a simpler solution, I will certainly examine it with an open mind!

Possible (0)

Anonymous Coward | about a year and a half ago | (#41161335)

Where is the Coesite and what is the condition?

And when found are there neutron damage tracks in the crystals?

!

I expect no replies to this message and the Moderator will delete it, obviously. .|.. (the 'Bird' ... in ascii)/

GPS (0)

Anonymous Coward | about a year and a half ago | (#41161615)

35.315003,-84.982424

Re:GPS (0)

Anonymous Coward | about a year and a half ago | (#41161631)

http://maps.google.com/maps?hl=en&ll=35.315046,-84.982381&spn=0.006872,0.010847&t=h&z=17

Can someone go check my impact crater candidates? (1)

Skapare (16644) | about a year and a half ago | (#41161749)

Can someone please check my impact crater candidates? Maybe they have already been determined.

Re:Can someone go check my impact crater candidate (2, Informative)

Anonymous Coward | about a year and a half ago | (#41163065)

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 to the east suggests it's a chance erosion feature between two different rock types of different toughness. If you look around that area you'll see there are lots of other eroded bowls. These are common shapes that peaks and ridges take as they erode.

Number 3 is I think called Burke's Garden, representing an eroded structural dome in an area of complex folding and thrust faulting in the ancient roots of the Appalachian Mountains. The outer, younger, sandstone layer was eroded way providing access for the elements to go to work on the less resistant shale and Knox Group limestone and interior. If you scroll around a bit you can see many ridges running running along the mountains, some of which are folded, faulted, and eroded in to similar structures -- just generally with a finer aspect ratio. This section of strata just happened to get abused by the just right combination of folding and thrust faulting in the right places to make the structure look a little rounder than most. Simple geologic mapping (which has already been done -- you just need to find a copy of the maps) should very conclusively demonstrate the structural features you see here are exclusively accounted for by the conventional compressive orogenic processes that formed the core of the ancient Appalachian Mountains.

Re:Can someone go check my impact crater candidate (0)

Anonymous Coward | about a year and a half ago | (#41163855)

'Tis a shame you're an AC for then I could mod you up.

where (1)

pwnstar23 (2717703) | about a year and a half ago | (#41161877)

where is Tennessee, azeroth or tyria?

Re:where (0)

Anonymous Coward | about a year and a half ago | (#41162265)

Nerd jokes don't really work when the premise is that you don't know anything about it.

Flaky evidence at best (1)

Dr La (1342733) | about a year and a half ago | (#41164507)

I don't think that it is "pretty obvious it is a crater". Prime evidence is missing or not well enough illustrated.

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 of cosmic dust for this sedimentary regime

What is needed is:

a) a clear record of a breccia fill;
b) a clear record of overturned rim strata;
c) a clear record of shock-deformed quartz;
d) more convincing examples of shatter cones;
e) more convincing examples of impact melt breccia, including identification of the mineral phases that associate with such rock.

The presence of clear meteoritic components (geochemically shown to be extraterrestrial in composition) in the crater sediments would be a good argument as well, but they are not always preserved in genuine meteor craters. The magnetic particles you present do not count as such, as I already pointed out.

Regarding (d) and (e): the photographs of purported specimens provided are far from convincing. The "shatter cone" actually looks like a shard of rock with a conchoidal fracture on the ventral face, not a 3D shatter cone. And the "melt glass"? Not clear enough from the pictures: it could be anything. The "tortured rock" (purported impact melt) actually looks like a porous carbonate such as you can find in karst features, not like a vesiculated impact melt.

Acid Test Says Not Carbonate.. (1)

tetrahedrassface (675645) | about a year and a half ago | (#41164855)

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?

Re:Acid Test Says Not Carbonate.. (0)

Anonymous Coward | about a year and a half ago | (#41167923)

Dolomite will not react much with acid unless it's HCl and you powder the sample first (scratching it and then applying 10% HCl is sufficient). Even so, dolomite will develop cave systems and karst terrain. It will happen more slowly, but for Ordovician bedrock in the Appalachians (250 Ma or so) time for karst development probably isn't an issue.

Even if the sample isn't dolomite, it doesn't mean the bedrock isn't mainly dolomite. The samples you are finding could be the stuff left behind that *didn't* dissolve.

Anyway, if you have eliminated dolomite and limestone for your sample, that may be useful, but any impact melt should consist of the melted equivalent of whatever the target rocks are, sometimes with pieces of relatively unaltered rock within the melt (i.e. impact breccia).

Location? (0)

Anonymous Coward | about a year and a half ago | (#41167241)

Maybe I'm blind, but I couldn't find this thing's latitude/longitude location, anywhere. I tracked it down using some of the pictures on the guy's website.

I found that it is located at: 35.313724 N and 84.977574 W [google.com]

Here's the site in question (1)

Trailer Trash (60756) | about a year and a half ago | (#41167585)

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 ignore the haters and keep on it. I remembered this post from a couple of years ago and the vitriol then. Keep on it. Worst case is you prove it's a sinkhole. But at least you've done something, learned a lot, educated others, etc. It's interesting work, and even if it is a sinkhole it's a freaking monster of a sinkhole - still interesting in its own right. And a sinkhole that big is draining into a sizable cave.

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