# How long would it take Nature to destroy the evidence of human existence? **URL:** \ **Category:** Great Debates\ **Created:** [April 4, 2006, 10:39am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228 "2006-04-04T10:39:40Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [April 5, 2006, 2:28pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/61 "2006-04-05T14:28:33Z")
I, for one, welcome our giant lobster overlords. Well, _somebody_ had to say it… ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [April 5, 2006, 2:29pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/62 "2006-04-05T14:29:54Z")
> [@Lemur866](#): > > Glass objects could last for hundreds of millions of years. However, they are likely to survive only if they are buried, and the OP specified no archeological digs. However, they could turn up on the surface after being buried (and then exposed by erosion). There would probably be a steady replenishment of random glass objects on the surface for a few million years after humans disappeared. ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [April 5, 2006, 2:33pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/63 "2006-04-05T14:33:59Z")
> [@Gorsnak](#): > > Well, actually the damage to the pyramids is due to over 4500 years of sandblasting. So we’re only talking about 220 times the damage they’ve taken so far. Considerably less than that – much of the historical damage to the pyramids is deliberate quarrying, not erosion. ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [April 5, 2006, 2:37pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/64 "2006-04-05T14:37:02Z")
> [@Blake](#): > > I believe that there are places where fossils that were buried for eons have been revealed via erosion. If your sole point here is that some fossil humans might by some weird chance be revealed in this way then I accept the point. Unlikely since very few fossils are every revealed in that way in a manner where they can be seen for what they are to an untrained person. Normally a few points are revealed then the rest is revealed by digging. But we are not allowed to dig. Interpreting that stipulation in the OP to mean “no digging to reveal additional features of some interesting thing you see in plain sight” strikes me as utterly preposterous. ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [April 5, 2006, 2:42pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/65 "2006-04-05T14:42:29Z")
> [@Blake](#): > > I’m getting the impression that to you a tiny pottery shard less than an inch long or a single molar will constitute evidence that humans exist. I grant that a molar doesn’t tell you that it used to belong to an intelligent creature unless you already know that much. However, the pottery shard is quite definitive, unless you known of some natural process that creates bits of ceramic that have shapes indicating that they used to be part of a container. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [April 5, 2006, 3:20pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/66 "2006-04-05T15:20:18Z")
> [@Blake](#): > > Nobody is saying that a lot of shit won’t be fossilised. The problem is that you are arguing a lot of recognisably human stuff will be fossilised and revealed again in a from that immediately constitutes evidence of human existence. As I have pointed out it is the idea that it will present in a manner that is evidential with no excavation that is incredibly improbable. Probably true with no excavation. > [@Blake](#): > > And I’m pointing out all the reasons why that is so remote as to be impossible. You are basically suggesting that an entire city by somehow well constructed enough not to collapse in the thousands of years it will take to be buried. How could that even be possible. Yes, thats what I’m saying. Why is it implausable that a modern city could remain relative intact for a few thousand years it would take to be buried? Could you explain why you think this is so out landish an assertion…in light of the fact that ancient cities lasted this long in just about ever imaginable environment on the earth? > [@Blake](#): > > How could that happen? A river or sea simply silts over, a dinosaur or tree gets buried. How can you silt over or bury an entire city? How can you silt over or bury a building and still allow it to retain its shape in any recognisable form? I have seen trees and bones being washed down rivers, I can’t see any plausible mechanism whereby a building or entire city can be swept down the river and be any more than scattered splinter by the time it reaches the delta. Can you explain what is holding the building together during this trip? Before I bother digging up (hehe) some cites on ancient cities that were buried despite being abandoned let me make sure I’m clear on what you are saying. You seem to be saying (repeatedly) that there is no natural mechanism for burying a city completely except, what? Human occupation? > [@Blake](#): > > Do we? Can you give some examples? Things reasonably well preserved have been found buried in the clay of tells, or in caves or even buried in sandy loam. But can you name one archaeological find that was buried in sand of Egypt? Well, I seem to recall a Muslim city swallowed by the desert and buried in sand. Also, I’ve seen ancient cities in the America’s that were buried basically due to becoming overgrown with jungle growth after being abandoned and eventually buried due to plant decay…plain old dirt. Then there is the odd volcanic ash burial, such as the two famous Roman cities and a less famous village in the South Pacific. And IIRC (since you asked about Egypt) wasn’t the capital of Tut’s father rediscovered essentially buried in the Egyptian sand after being abandoned following the disasterous Amon cult? > [@Blake](#): > > Can you elaborate on what process could possibly preserve a city or a building for a million years? Are you talking about being rolled down a river an buried in the delta? Or are you suggesting that silt might start building up vertically, since siltation is the mechanism by which streams and oceans are preserved? Well, thats not what I was getting at, but now that you mention it…how about a city like New Orleans? Wouldn’t need to ‘roll’ it anywhere, right? 😛 > [@Blake](#): > > Once again though you seem to be suggesting that features that would allow someone who doesn’t already have evidence to identify human remains revealed in this way. How could that be done? Even with training and prior evidence it’s almost impossible to identify exposed remains without digging. You are probably right…it would take a tremendous amount of luck for something to be buried and re-exposed…AND to have someone looking in the right place at the right time…AND to be able have the training and knowledge to understand what they were looking at. > [@Blake](#): > > And how would those lines be preserved exactly? How did this city get buried in loco sans disturbance? By what plausible mechanism could that occur? How could you bury Dallas before fires, tress and general erosion obliterated those straight lines? The same way ancient abandoned cities were eventually buried of course. Not all buried cities were buried by subsequent occupation after all. > [@Blake](#): > > After 1000 years, sure. But we are talking about after a million years, and after the city has been buried. We never find ancient cities that way. 😛 This would be because there ARE no cities older than a few thousand years. But its not true that we never find disturbances visible from the air that indicate that SOMETHING artificial lies under the ground. Woodhenge in England was pretty much discovered in this way (as a group of discolored depressions visible only from the air)…as well as the out lieing and older wooden structure that became Stonehenge. > [@Blake](#): > > Can you find any evidence that any natural feature was ever exposed in a form which provided evidence for what it was without requiring any digging, and to people who had no reason prior evidence that such a thing had existed? Well, the last caviot is the killer for this one…i.e. ‘people who had no reason prior evidence that such a thing had existed’ kind of kills the whole thing. Certainly there have been discoveries on the surface of preserved natural features…Gobi Desert and in the South West such things have been discovered. But generally (trained) people were actually out looking for them. I suppose there has to be SOME example of a complete amature making such a discovery at random though. > [@Blake](#): > > It makes no difference. Fossilisation is about probabilities. If 1 in 1 billion get fossilised it doesn’t matter if that billion all lived at once or lived scattered over a million years. Lets take that 1 in a billion chance then as a good rough estimate. Aren’t there over a billion human structures in the world? 😉 > [@Blake](#): > > Do you honestly not see the difference between “hominid artefacts found” and “hominid artefacts found undamaged and sitting fully exposed and recognisable without any need for digging”? It wasn’t exactly the point I was trying to make. What I was saying was that we have found more artifacts from our more recent ancestors as we close the gap in time towards the modern. One of the reasons (I was speculating) is simply because as we close that gap our ancestors became both more numerous…AND left more, and more sophisticated, behind. > [@Blake](#): > > Good grief, you must be doing this to irritate. You can’t really believe that something in a glacier will last a million years can you? And if you are I will give up right now. No, it was one of those ‘joke’ things…i.e. it was supposed to be humorous. I wasn’t trying to irritate you, though you seem to irritate easily. 😉 > [@Blake](#): > > Half buried steel huh? You’ve just created a galvanic cell Please explain how you can half bury steel without it rusting away? Have I? In every possible case? And what of soft iron, copper and bronze (even textiles) occationally found from ancient days? But you are kind of missing my point. I wasn’t claiming that the steel wouldn’t eventually rust away…it certainly would in a million years (I imagine SOME of the more exotic alloys could last that long in certain conditions…Titanium perhaps). But the FORM of the building could (potentially) remain long after the original material of the building disintigrated. Sort of like wooden structures excavated from ancient buildings…we are able to tell SOMETHING was there, and even see the patterns of the buildings. Now, if wooden structures FORMS could be preserved for many thousands of years (some I’ve seen 5000 or more), surely its possible that, in the right circumstances, concrete and steel buildings would ALSO leave a ‘foot print’ behind showing clearly that SOMETHING was there…and something that was not natural. Of course, most likely you’d have to dig for it…I’m simply musing that perhaps such a site could be later re-exposed to be seen from the air. Improbable but I really don’t see that its as impossible as you are making it out to be. > [@Blake](#): > > Where are these sediments coming form? How are they getting into the city? Wind blown dirt and dust. Plant decay. Perhaps the occational flood if its in a flood plain. The usual way ancient cities were buried after being abandoned. > [@Blake](#): > > I really can’t see any substance at all in your posts. It’s all just somehow this happens then somehow that happens by some remote chance. Yet you clearly have no concept of how these things actually work. I’m most amazed by your beliefs that glaciers last millions of years and that somehow you can compress sediment in building sufficiently to solidify it yet put no pressure on the floors, roof or walls of the structure. There isn’t a lot of substance to ANY of our posts on this subject man. Thats because its outside of any real world experience we could possibly have. No one knows what effect such a large period of time could or would have on an entire worlds civilization. We aren’t talking about one isolated civilization here but the cities, towns, villages of an entire species who inhabits an entire planet, in every possible environment. We can’t (necessarily) judge the effects on what we would leave behind based on what our hominid ancestors did or didn’t leave behind because frankly they didn’t leave much…there were never that many of them, they didn’t construct in perminent materials and they weren’t spread out over the entire earths surface. -XT ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [April 5, 2006, 5:37pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/67 "2006-04-05T17:37:29Z")
On caveat is that we can’t judge solely on current archeological finds because of the selection bias of archeology. The jargon term for this is taphonomy…things don’t get buried and preserved at random, so what we dig up isn’t a representative sample of ancient life. So useful tools are very rare, because people are very unlikely to just drop them, and if someone does drop them someone else is likely to pick them up again. So we don’t expect to find heaps of gold lying out on the ground, because someone is bound to pick it up long before an archeologist gets there. What we do find is often literally garbage, with the occasional burial, the occasional deliberately concealed treasure trove, and the occasional lucky find. And we don’t expect cities to be abandoned very often, because if there was a reason for a city to exist it is likely that the city will continue to exist. People don’t just abandon a city unless there’s a very good reason for the city to be abandoned, like if it gets buried under meters of volcanic ash. That being said, I’m coming around to the viewpoint that after a million years there won’t be very much visible just walking around, maybe only a few places on earth. But the minute the aliens start digging they’re going to come up with all kinds of things, and I expect glass objects to be the most numerous. And evidence of excavation will be everywhere, provided the aliens start excavating on their own. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [April 5, 2006, 9:50pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/68 "2006-04-05T21:50:33Z")
BTW, if you’re interested in speculation on the future of Earth-without-humanity, this is a good place to start: [http://en.wikipedia.org/wiki/After\_Man](http://en.wikipedia.org/wiki/After_Man) ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [April 6, 2006, 12:09am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/69 "2006-04-06T00:09:49Z")
> [@MrDibble](#): > > I know this. I also know that “swamps and forests” are in no way, shape or form semi-arid biomes. Really? Can we please have a reference for this extraordinary claim? Once again you are simply spouting off when you have no idea what you are talking about. Swamps and forests are both common features of semi arid biomes. [http://www.natureserve.org/explorer/servlet/NatureServe?searchSystemUid=ELEMENT\_GLOBAL.2.722943](http://www.natureserve.org/explorer/servlet/NatureServe?searchSystemUid=ELEMENT_GLOBAL.2.722943) [http://www.nmnh.si.edu/botany/projects/cpd/sa/sa24.htm](http://www.nmnh.si.edu/botany/projects/cpd/sa/sa24.htm) [http://geology.rutgers.edu/Ashley/Owens\_Diatom\_Paper.pdf](http://geology.rutgers.edu/Ashley/Owens_Diatom_Paper.pdf) [http://www2.unesco.org/mab/br/brdir/directory/biores.asp?mode=all&code=BKF+01](http://www2.unesco.org/mab/br/brdir/directory/biores.asp?mode=all&code=BKF+01) [http://www.pr.mq.edu.au/macnews/ShowItem.asp?ItemID=129](http://www.pr.mq.edu.au/macnews/ShowItem.asp?ItemID=129) Can we now please have a reference for your claim for what you ‘know’, ie that “swamps and forests” never comprise semi-arid biomes. Of course I ask you this purely to seek your admission that you were spouting off since seasonally inundated swamplands, delta swamps and gallery forests are so common in semi-arid biomes that nobody who has a clue what they are talking about would ever make such a ridiculous claim. > [@](#): > > I know this, too - but \*you \*were _misleadingly_ implying that parts of the Namib and Atacama were “forests or swamps” **in the last million years** - they were not. > [@](#): > > The Namib Dune sea, while not as old as the Namib overall, has been unchanged for millions of years… Cite. Ive produced a reference which says that it has not. > [@](#): > > I’d like a cite for the bits of it that were swamps or forests **in the last million years** , please. Right after we get your reference that seasonally inundated swamps and gallery forests" are in no way, shape or form semi-arid biomes. It seems clear at this stage that you have little idea what you are speaking of, especially since you think that rivers changing course are irrelevant to the distribution of gallery forests. But I await your references with bated breath. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [April 6, 2006, 12:29am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/70 "2006-04-06T00:29:49Z")
> [@xtisme](#): > > Yes, thats what I’m saying. Why is it implausable that a modern city could remain relative intact for a few thousand years it would take to be buried? Could you explain why you think this is so out landish an assertion…in light of the fact that ancient cities lasted this long in just about ever imaginable environment on the earth? Ancient cities didn’t last that long. Solid stone structure like temples lasted that long. The cities were long since obliterated. > [@](#): > > Then there is the odd volcanic ash burial, such as the two famous Roman cities and a less famous village in the South Pacific. OK, so you are stipulating Pompeii type events, and that\is somehow more probable? > [@](#): > > wasn’t the capital of Tut’s father rediscovered essentially buried in the Egyptian sand after being abandoned following the disasterous Amon cult? Was it? I’ve asked for evidence of these cities that were buried and then showed up in recognisable form with no excavation. Do you have any? > [@](#): > > how about a city like New Orleans? Wouldn’t need to ‘roll’ it anywhere, right? How is New Orleans going to be buried before it burns or is overgrown? > [@](#): > > Well, the last caviot is the killer for this one…i.e. ‘people who had no reason prior evidence that such a thing had existed’ kind of kills the whole thing. Certainly there have been discoveries on the surface of preserved natural features…Gobi Desert and in the South West such things have been discovered. But generally (trained) people were actually out looking for them. I suppose there has to be SOME example of a complete amature making such a discovery at random though. Well since you are repeatedly claiming that such things happen can you produce evidence. > [@](#): > > Lets take that 1 in a billion chance then as a good rough estimate. Let’s not. Nowhere near 1 in a billion organism get fossilised and re-exposed. If they did every square inch of the planet would be paved with beetle fossils alone. > [@](#): > > Have I? In every possible case? And what of soft iron, copper and bronze (even textiles) occasionally found from ancient days? Please present evidence of these soft iron, copper and found from ancient days that were ever partially buried. You seem to be taking on faith that these things existed. Do you have any actual evidence? > [@](#): > > But the FORM of the building could (potentially) remain long after the original material of the building disintigrated. How can the form of a building remnain when the building has totally collapsed because the supports rusted out? > [@](#): > > Sort of like wooden structures excavated from ancient buildings No excavation allowed. > [@](#): > > surely its possible that, in the right circumstances, concrete and steel buildings would ALSO leave a ‘foot print’ behind showing clearly that SOMETHING was there…and something that was not natural. Is it? Based on what? > [@](#): > > Wind blown dirt and dust. Enough windblown dust to bury a building? So you are talking about a region with moving dunes. We’ve already discussed the problems with this. > [@](#): > > Plant decay. Inside a building? How? > [@](#): > > Perhaps the occational flood if its in a flood plain. On a floodplain, yet the foundations remain solid and the building remains upright. How? > [@](#): > > The usual way ancient cities were buried after being abandoned. Once you produce this evidence of these ancient cities that were buried naturally and remained recognisable with upright buildings we’ll be bale to evaluate these claims. I notice that you ignored numerous questions that I put to you. Understandable given that they contradict the laws of physics, Jim. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [April 6, 2006, 5:51am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/71 "2006-04-06T05:51:06Z")
Gods fuzzy balls. > [@Blake](#): > > Ancient cities didn’t last that long. Solid stone structure like temples lasted that long. The cities were long since obliterated. Well yes…mainly because in many ancient cities only temples were solidly constructed. Perhaps you’ve noticed that we construct a lot more robustly in the last few odd thousand years? I’m not claiming that very many modern buildings would last (even buried and protected) for the whole million years…only that if ancient temples in abandoned cities could last long enough to be buried that its plausable that SOME modern buildings from any given city COULD last an equally long time…time enough to be buried. Why is this so implausable to you? > [@Blake](#): > > OK, so you are stipulating Pompeii type events, and that\is somehow more probable? No…I merely listed it as another possibility. You seem to want me to predict the future entirely based on the past…and to do so as if I’m some kind of seer. I am merely pointing out that volcanic ash would also be a possibility for human structures or artifacts that could be buried and exposed at some later date. Could you tell me why this is an impossibility? > [@Blake](#): > > Was it? I’ve asked for evidence of these cities that were buried and then showed up in recognisable form with no excavation. Do you have any? So, the stipulation is that it has to be found without excavation? Not that a city could be buried? Off the top of my head I suppose the tomb of the first emperor of China (Qin/Chin Dynasty) would qualify (its an entire necropolis after all). Basically found by a farmer falling in a hole in the ground which was part of the outer works of the tomb. Our lazy alien visitors would need to exert themselves enough to actually walk around but I guess if you won’t even try and bend your mind to anything other than whats already happened in our own archaeological history then that would be a good example. If you remain unconvinced that people have stumbled on archaeological sites and made discoveries without digging a single spade of dirt (i.e. by accident) then I can probably dig up something or other in Central or South America as well. I don’t know any specifics off the top of my head but I recall several cities being discovered when someone stumbled on half buried ruins…or again fell in a hole. > [@Blake](#): > > How is New Orleans going to be buried before it burns or is overgrown? Um…in the next hurricane we don’t do anything about that causes the city to flood perhaps? How are you making these predictions that it will necessarily ‘burn’ or become ‘overgrown’ before it silts up btw? Were I to speculate you are doing it the same way I am…you are making educated guesses. You don’t seem to realize that you keep asking me for (IMHO) ridiculous cites backing up what has happened in the past…while making speculations like this based on nothing more than your own imagination. I’d say that the odds of N.O. being buried before it burns down or becomes overgrown are fairly good…it being in a great big bowl below sea level and all. Couple that with the fact that its only human intervention in dredging the Mississippi and keeping the delta clear (for shipping) that has caused the ground level to sink…take the humans out and nature will probably do its thing. Again, why do you find this completely outlandish a concept? Since we are talking about time frames so far out there we can merely speculate about possibilities…even if they are remote. > [@Blake](#): > > Well since you are repeatedly claiming that such things happen can you produce evidence. Well, I have neither the time nor the energy for an exhaustive search…especially for something that, to me, is really not disputable. However, I found [this](http://www.travelsd.com/thingstodo/archaeology/paleontology.asp) about an ancient watering hole discovered by a couple of hikers (no digging necessary). > [@](#): > > The dig at the Conata Picnic Site was expected to take a few hours but has actually lasted 12 years. Discovered by accident in 1993 by two park visitors, the site is thought to represent a 32 million-year-old watering hole where thirsty animals became stuck. When hungry carnivores attempted to prey on the trapped animals, they too were caught. Paleontologists have uncovered 12 types of animals, including a cowsized rhinoceros, a pig-like animal, a small, three-toed horse, a pomerian-sized dog, a type of tortoise and a rabbit-ancestor. So, here is a natural feature that was buried and exposed and discovered by some hikers. Since you seem to require that any speculations about what might happen need to have already happened to become real…well, there you go. I’m reasonably confident this is not the only time in history that ancient natural geography has been exposed and found…without lifting a shovelful of dirt. Another example would be…dinosaur foot prints. Again, I’ve seen them and know of a few instances where they were discovered by some mopes just hiking about. In fact I watched a show on the discovery channel the other day about some Giant Sloth foot prints found in South America (I think it was in Chile) by a fisherman after a violent storm…the foot prints were something like 50,000 years old IIRC. > [@Blake](#): > > Please present evidence of these soft iron, copper and found from ancient days that were ever partially buried. [Certainly](http://www.c-e-n.org/archaeology.htm): > [@](#): > > The Adabrock Hoard > When Donald Murray from Adabrock was cutting his peats in May 1910, in what is now the Eorodale Park (An t-Slugaid), he found a group of objects which proved to be of great significance. > The find comprised: three razors, an axehead, a gouge, a hammerhead, a chisel, a spearhead, two whetstones, gold glass and amber beads and fragments of bronze sheet. > > The tools and weapons were made of bronze and archaeologists tell us that they were made before 750 BC, during the Bronze Age. What Donald Murray discovered was one of the most important finds from the Bronze Age in Scotland. The items are now displayed in the National Museums of Scotland, in Edinburgh. Blake…come on. I’ve SEEN iron and bronze weapons found in ancient river beds (who dried up and were buried), in fields, in tombs. YOU’VE seen these things if you’ve ever been to a museum…especially one in England or on the continent. They are all over the place. I’ve ALSO seen them in Greece. Now, granted many of them were excavated…but some were simply found by some bloke digging peat or plowing his field. Some were found during new construction (lots of stuff in Greece has recently been found this way) within modern cities that sit on top of much older cities. Some were found as the result of a flood or other natural event that exposed the layers the artifacts were buried at. > [@Blake](#): > > How can the form of a building remnain when the building has totally collapsed because the supports rusted out? How can the form of, say, dinosaur foot prints in MUD last…when the dinosaur has moved on and the original material is mud? If a building made of concrete is buried AND filled in…well, where would the collapse come from exactly? There is dirt both inside and out after all. I have no idea how long concrete buried in dirt could or would last, but the form (like that of those foot prints) could potentially remain to be exposed at a later date…again, much like those foot prints. If MUD can do this in special circumstances I don’t see the objection to concrete, brick, adobe, stone, or other building materials. > [@Blake](#): > > Is it? Based on what? Speculation and extrapolation like the above. Extrapolation based on some of the cities/temples I’ve seen excavated in the new world (and how they pretty uniformly filled in with tightly packed dirt in their interiors)…and speculation on how a modern building in the right circumstances may react in similar ways. What are you basing YOUR pondering on pray tell? > [@Blake](#): > > Enough windblown dust to bury a building? So you are talking about a region with moving dunes. We’ve already discussed the problems with this. Um, no. Do you really not know the mechanism that abandoned cities become buried? There isn’t a lot of windblown dust (or sand for that matter) in the jungles of Central and South America…yet whole temples and pyrimids have become buried after they were abandoned (and interestingly enough remain more or less intact, despite this rough treatment). Its a combination of plant matter decaying coupled with natural things like floods and such. Really I can’t for the life of me understand your objections in many of these cases. You DO know that ancient cities were buried, don’t you? When they were rediscovered, many of them were intact…despite being buried. I can understand your objection about the OP specifying ‘no digging’, but I can’t for the life of me understand where your objections to some of this stuff is coming from. > [@Blake](#): > > Inside a building? How? :rolleyes: Let me ask YOU a question here (as to me this is getting a bit ridiculous…either you are pulling my leg or we have a serious disconnect somewhere). How do YOU account for city/temple complexes buried in Central and South American jungles after abandonment? What is the mechanism that allowed these huge buildings to become completely filled in with dirt and buried? > [@Blake](#): > > On a floodplain, yet the foundations remain solid and the building remains upright. How? The same exact way several ancient sea ports were preserved (the Roman port of Ostia was on a flood plain IIRC and buried in a similar manner). > [@Blake](#): > > Once you produce this evidence of these ancient cities that were buried naturally and remained recognisable with upright buildings we’ll be bale to evaluate these claims. Well, I’ve stated how ancient cities were naturally buried already. I make no claim to being an expert in archaeology, but I think I’ve given a pretty good (rough) account of the mechanism. If only cites will satisfy you…well, maybe someone else with more energy will dig them up. As to how they would be remain recognizable after such a long period…well, here we are in the realm of speculation. Obviously no buildings from a million years ago are about for us to check…mainly because there WERE no buildings 1 million years ago for us to check things against. However, other natural features from a million years ago (or longer) have certainly been discovered…such as the dinosaur foot prints left in mud I mentioned earlier. Speculating that perhaps a buried modern building could solidify and retain its shape and form (much like those foot prints), and then be exposed at a later date (again, like the foot prints), I dont think its unreasonable that our lazy aliens may stumble upon such a form and wonder what it was. We have an entire WORLD full of human cities and artifacts in ever conceivable environment. To me it would be incredible if NOTHING survived. Whether or not whatever managed to survive also had the great good fortune to be exposed convinently where the lazy aliens happened to be looking…well, I’d say the odds would be long. But…its not outside of the realm of possibility, which is all I’ve been saying all along. Anyway, I think I’m done here. I’m sure you aren’t satisfied with any of my post as it doesn’t have a million (to me worthless) cites and expert opinions. Maybe someone else wants to take up the torch at this point and carry on…and will hopefully do a better job of it than I have. To me its just been an interesting mental excersize dredging up half remembered bits of knowledge gleened 15 years ago in various anthropology and archaeology classes at university and attempting to extrapolate that half remember munge into speculations about what MIGHT happen with reguards to the OP. -XT ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [April 6, 2006, 7:31am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/72 "2006-04-06T07:31:02Z")
> [@xtisme](#): > > mainly because in many ancient cities only temples were solidly constructed. Perhaps you’ve noticed that we construct a lot more robustly in the last few odd thousand years? No, we don’t. A reinforced concrete building isn’t particularly robust and rewuires constant maintenance to remain upright. > [@](#): > > Why is this so implausable to you? For the reasons I’ve already outlined. Concrete itself decays. Reinforcing half buried leads to concrete cancer etc. Stone is naturally resilient (obviously)\> Concrete and metal are not. > [@](#): > > Could you tell me why this is an impossibility? I never said it was impossible. Teleportation to the moon is also possible. > [@](#): > > I suppose the tomb of the first emperor of China (Qin/Chin Dynasty) would qualify (its an entire necropolis after all). Really? Wasn’t it buried almost as soon as it was built, being in essence a burial mound? > [@](#): > > … I can probably dig up something or other in Central or South America as well. I still await your references. > [@](#): > > How are you making these predictions that it will necessarily ‘burn’ or become ‘overgrown’ before it silts up btw? Because that area grows vegetation, lots of it, and is a seasonally inundated. That means that the vegetation alone will burn at least every 5 years on average. If the grass and herbage burns how can the city _not_ burn? > [@](#): > > you keep asking me for (IMHO) ridiculous cites backing up what has happened in the past No, I ask your for cites that you state as fact happened in the past. Now if you were to ask me for a reference that the seasonal swamps of the Mississippi delta burned on average every 5 years I could provide that. That is the difference between your claims and mine. > [@](#): > > I’d say that the odds of N.O. being buried before it burns down or becomes overgrown are fairly good…it being in a great big bowl below sea level and all. Can you explain how a lightning strike could [I[not\* initiate a fire within 10 years? Or failing that can you explain how the grass will burn but the buildings will not? > [@](#): > > However, I found … about an ancient watering hole discovered by a couple of hikers A water hole? That’s your example? A natural depression became silted over is your example of a preserved natural feature that is evidence of humanity? I’m not at all sure what point you are trying to make here. > [@](#): > > Blake…come on. I’ve SEEN iron and bronze weapons found in ancient river beds And nobody ever denied they existed. Now can you produce those references that they were ever half buried, as opposed to immediately fully submerged? That was what was requested. > [@](#): > > If a building made of concrete is buried AND filled in…well, where would the collapse come from exactly? You still haven’t explained how concrete building could be filled with mud without being crushed flat. I’ve asked several times now. > [@](#): > > There is dirt both inside and out after all. How? [quote] Extrapolation based on some of the cities/temples I’ve seen excavated in the new world (and how they pretty uniformly filled in with tightly packed dirt in their interiors) [/quote Evidence of same? > [@](#): > > Do you really not know the mechanism that abandoned cities become buried? I asked. > [@](#): > > There isn’t a lot of windblown dust (or sand for that matter) in the jungles of Central and South America…yet whole temples and pyrimids have become buried Evidence please. Evidence of even one city that was buried. [quote] Really I can’t for the life of me understand your objections in many of these cases.[/qupte] Total lack of evidence. > [@](#): > > How do YOU account for city/temple complexes buried in Central and South American jungles after abandonment? Evidence of huge buildings to become completely filled in with dirt and buried please. > [@](#): > > Well, I’ve stated how ancient cities were naturally buried already. But have been totally unable to provide evidence that it ever happens despite numerous requests. > [@](#): > > If only cites will satisfy you…well, maybe someone else with more energy will dig them up. If you can’t provide evidence for your claims then you have nothing. What are you doing in GD? ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [April 6, 2006, 8:59am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/73 "2006-04-06T08:59:13Z")
> [@Blake](#): > > Really? Can we please have a reference for this extraordinary claim? > > Once again you are simply spouting off when you have no idea what you are talking about. Swamps and forests are both common features of semi arid biomes. Fine, fine, you’re right, I mis-spoke. “Swamps or Forests” can form a _ **part** _ of a semi-arid or arid biome. I’ve been to the Okavango, I should have phrased that better. Happy? My **point** , however, was that “swamp or forest” can’t be[ _the entirety_ of the semi-arid or arid **biome** \*for the Namib or the Atacama \* (you know, the 2 deserts whose young ages I objected to, the whole point of this little hijack?) Nice misdirection, though. Still doesn’t back your claim that the current areas of the Namib and Atacama were **“forests or swamps”** (as in “mostly consisting of”, unless you want to backpedal away from that statement) in the last million years, though. Everything else is just obfuscation. Your cite , BTW, merely said that the oldest continuous arid region is a certain age, it said nothing about the age of the Namib or Atacama And even that’s not correct - shall we play “duelling cites”?. Yours is from 1983. Mine is from [2005](http://geology.geoscienceworld.org/cgi/content/abstract/33/4/321) . See there where it says " these surfaces have been barely affected by erosion since 25 Ma"? When’s that? Why, it’s the Oligocene. What’s that you say? That’s not the Namib? Well, you did mention the Atacama too, but OK, let’s play again- [man, this Dunai guy gets around!](http://www.xs4all.nl/~landform/namib-results.htm) . " Aridity of the Namib Desert is generally assumed to have started with the onset of Benguela upwelling in the SE Atlantic at 10 to 15 Ma and to have prevailed ever since. … Our results generally confirm previous work. " I’ll admit that the date given there is later than my earlier estimate of 23Ma, but I was going by the opening of the seaway not the start of cold upwelling. Feel free to jump all over this little detail if you must. Ignore the fact that current geochemistry work makes a mockery of your cite. > [@](#): > > Right after we get your reference that seasonally inundated swamps and gallery forests" are in no way, shape or form semi-arid biomes. You _do_ know the definition of a biome, right? A seasonally inundated swamp, or a gallery forest, can not **be** a biome\*. “Namib Desert” is a biome. “X River Gallery Forest” is not. Learn the lingo before you spout it off. \*Unless the desert is just criss-crossed with exotic rivers, all with associated forests. I think we’d pick something like that up in the geologic record, though. ---
**Author:** ![Spoke](https://avatars.discourse-cdn.com/v4/letter/s/a88e57/32.png) [@Spoke](https://boards.straightdope.com/u/Spoke)\ **Post date:** [April 6, 2006, 2:10pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/74 "2006-04-06T14:10:31Z")
**Blake** , do you really not understand that decaying vegetation deposits soil? That a building left abandoned will sprout vegetation in its interior as its roof decays? That a building overgrown with vegetation will eventually be a “buried” building, with soil both inside and out? Do you really need a cite for a process that anyone with an overgrown back yard can observe? Numerous stone structures in Central America have been “buried” in just this way. (Not to mention the brick corner post on my own property, buried by decades of ivy growth and soil accumulation until I dug it out.) ---
**Author:** ![renzuken\_x\_2](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@renzuken\_x\_2](https://boards.straightdope.com/u/renzuken_x_2)\ **Post date:** [April 9, 2006, 4:55am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/75 "2006-04-09T04:55:57Z")
i think stonehenge would be the longest suviver, or something like that. think about it, buildings are always beeing repaired but stonehenge holds up. you could argue that buildings only need repair because there used on a daily basis but stonehenge has 1000’s of years behind it and it still looks good. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [April 9, 2006, 5:40am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/76 "2006-04-09T05:40:22Z")
I think stonehenge has been repaired (well, restored) at least once…perhaps several times. I doubt it would last a million years in the open…though I suppose its possible that the climate or environment around the plain may change enough that it could be buried and later exposed. Except according to Blake buildings are never buried by natural causes of course…or if they are they are uniformly destroyed by the process of being buried. 😉 -XT ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [April 9, 2006, 9:25pm UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/77 "2006-04-09T21:25:38Z")
> [@Alive At Both Ends](#): > > A million years pass by. Would any evidence still be visible (to an alien visitor) that we had ever been here? > [@Science Officer Pthfx](#): > > “Captain Zorklon, this planet’s atmosphere contains more Tc[sup]99[/sup] than can be accounted for by natural processes.” > > Zorklon scratched his fluffle pensively. * * * ---
**Author:** ![renzuken\_x\_2](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@renzuken\_x\_2](https://boards.straightdope.com/u/renzuken_x_2)\ **Post date:** [April 10, 2006, 1:33am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/78 "2006-04-10T01:33:32Z")
i know its ment to be on earth but what about all the parts or man made materials that orbit the earth from space shuttles, its a sure sign that something left the planet and beeing that in space theres not much that can erode the metal (well, not that i know of). ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [April 10, 2006, 1:55am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/79 "2006-04-10T01:55:44Z")
Blake, I think you’ve become unreasonable here. Now you’re finessing the demands for cites such a things ‘half buried’, etc. It seems to me that if a dinosaur can step in mud, and have us stumble across that footprint in very recognizable form millions of years later, then it’s hardly unlikely that of all the massive structures we have built, some will wind up being visible a year from now, even if in fossilized form. Is it so impossible to imagine say, a mudflow across an interstate hardening, then decaying away and revealing the imprint of a two-lane highway a few million years from now? And of course buildings get buried from the inside and out. You can drive all around North America and see old farm buildings that have essentially been reclaimed by generations of vegetation. You can find buried foundations all over the place. Granted, for any one of them to survive would be a miracle. But we have a planet full of such structures. Some of them will be protected in some fashion in volcanic floes, or be fossilized, or simply be buried in some stable form and uncovered by natural processes along the way. And I think you’ve hand-waved away Mt. Rushmore. What makes you think it won’t be around in 1 million years? According to the cite already made, the surface of it will have eroded about 100 cm by then. Given that the faces are 60 ft high, I think they’ll largely be recognizable as faces in a million years. Maybe not recognizable as individuals, but certainly as man-made structures. And sure, some of the features may be cracked apart and collapsed by water, but there are four of them, so we’ve got some redundancy. And yes, a natural disaster could obliterate it, but that’s not for sure. So I think we have to say that it’s _possible_ that Mt. Rushmore will be recognizable as something man-made in 1 million years, don’t you think? And if it’s possible, then if you add in all the other similar monuments around the world, it seems likely that at least one of them would survive. Not completely intact and undamaged, but recognizable as something artificial. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [April 10, 2006, 2:04am UTC](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228/80 "2006-04-10T02:04:30Z")
Hey, do satellites count? There are a few in extremely stable orbits that will be up for a long, long time, and are visible from earth. The [Lageos](http://www.earth.nasa.gov/history/lageos/lageos.html) satellites are expected to remain in orbit so long that they carry maps of the continents with them so that if they are ever discovered in the far future the discoverers will be be able to date them. Their orbits are expected to decay in about 8 million years. So we know that for at least 8 million years, there will be a visible record of a technological civilization orbiting the earth. [Previous page](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228.md?page=3) [Next page](https://boards.straightdope.com/t/how-long-would-it-take-nature-to-destroy-the-evidence-of-human-existence/351228.md?page=5)