Pre-historic civilisations.

[3point14]

Okay, so the thread title isn't great, but I couldn't think of a good one.

I was recently reading one of the Science of the Diskworld books in which is postulated (for no more than educational purposes) a race of intelligent dinosaur herders wandering across the plains some 66mya who, along with all traces of their existence, were wiped out when that big rock touched down in the gulf of Mexico.

It got me to thinking, how far advanced could any pre-historic, non human society have got before it would have left visible traces that we would have discovered by now? I don't have the necessary knowledge to speculate, I wondered if those who have might be able to?

[Overman]

Probably very nomadic...They would have to use fairly developed communication skills to take down something that big...Would have to develop tools...so some artifacts would be left behind...

The problem is that fossils are so extremely rare...It seems like we find them often, but if you think of the percentage of animals that actually get fossilized...

[Dancing David]

6o million years is a really long time. If they had technology there might be traces of that, if they had mining. But to find something like a building would be really, really rare.

This is part of why the Victorians and others used to talk about the 'Magdelenian explosion', as though europeans were the only ones to weave clth, make wooden tools and artifacts and have bone tools. The preservation of those items is about 14,000 years in most circumstances. The european artifacts were the better preserved, we don't have asian artifacts from that time frame. The asians and africans most likely did have them, they just didn't stay preserved. They rotted.

[Soapy Sam]

The two obvious remnants would be mining and quarrying, including the drilling of oil wells, which are buried structures which may well leave recognisable traces tens of millions of years hence.
The absence of near surface coal where we would expect it would suggest earlier mining. I've read of a couple of supposed ancient mines, but the evidence is very shaky indeed- bad archaeology linked to wishful thinking.

The OKLO reactors appear to be quite natural, though some woos would have us think otherwise.http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml

Of artifacts, glass and ceramic last longest, including natural glasses like obsidian. These can be produced at a very crude level of technology.

True high tech requires a large industrial base. That requires high population density and that requires a large agricultural base. That's people.

A creature which can eat easily year round requires no tech support , so might never produce it. Carnivorous dinosaurs for instance. While skull casts of late Cretaceous dinosaurs suggest intelligence in the range of birds or small mammals, there is no evidence of dinosaur artifacts, except nests and trackways. If there was a herder dinosaur, farming others, it might have constructed corrals or traps. None is known. Nor are dinosaur weapons- which might have been found associated with carcasses of hunted animals, for instance.
Would flint spearheads survive 65MY? Yes. But if one was found in the rib cage of a dead dinosaur, would it be recognised as such?
I think so.

WE look for fossils rather assiduously. The type of person who does so is unlikely to miss anomalies. It seems to be believed in some woo circles that archeologists and palaeontologists suppress or destroy evidence that does not fit conventional wisdom. This is silly. Such evidence would make a career.

So I think any level of organised culture in large land creatures would be spotted .

This need not apply to insect or marine life, or microscopic life- but we must draw a line somewhere.

[Wolfman]

I was recently reading one of the Science of the Diskworld books Ah, I'm a huge Pratchett fan, too :)
It got me to thinking, how far advanced could any pre-historic, non human society have got before it would have left visible traces that we would have discovered by now?
I'd argue that they would need to have reached a space-age level of ability to be sure of leaving such artifacts. Satellites left in wide orbits, monuments erected on the moon, etc. These are things which could reasonably be expected to last millions of years, particularly if done in multiples (to guard against accidental destruction).

On Earth, it would be possible for artifacts to last for millions of years (as we are able to easily demonstrate by the existence of fossils hundreds of millions of years old). However, the probability of them surviving would be fairly low, and the likelihood of them subsequently being discovered again would be incredibly low.

Consider an intelligent creature from the past, who is killed by their local equivalent of the 'mafia', their body disposed of in a convenient tar pit, or peat bog. That creature wears some form of clothing, has some form of ID, perhaps something like a cell phone, etc. Natural processes preserve that creature as a fossil; it would not be too wild to speculate that something else with it would also be preserved in one form or another (impressions, fossilization, preservation, etc.).

So I guess that you'd have to differentiate between the question what level a civilization would have to reach to have something of it preserved (and discovered) entirely by accident (I'd say this would be possible at any level of civilization), and what level a civilization would have to reach to be able to reasonably ensure that some sign of their civilization was still evident millions of years later (for which I'd consider you'd pretty much need a space-age level of civilization).

[fuelair]

Okay, so the thread title isn't great, but I couldn't think of a good one.

I was recently reading one of the Science of the Diskworld books in which is postulated (for no more than educational purposes) a race of intelligent dinosaur herders wandering across the plains some 66mya who, along with all traces of their existence, were wiped out when that big rock touched down in the gulf of Mexico.

It got me to thinking, how far advanced could any pre-historic, non human society have got before it would have left visible traces that we would have discovered by now? I don't have the necessary knowledge to speculate, I wondered if those who have might be able to?Far enough to knap flint (or equivalent) - since we can recognize knapping over random breakage, far enough to carve simple sculptures, far enough to paint on wall, far enough to make/carve anything that indicates it was made/carved and is not likely to break down completely.

[Gbob]

I think when you talk about a "lost" civilization, I would doubt that you could have development higher than basic metallurgy. At that point, artifacts left behind are unmistakable. More telling, one of the signs of an "advanced" civilization is that technology allows humans to gather in larger groups than in nomadic pre-technological societies. Large gatherings of people leave traces. Just as important, civilizations don't live in isolation. Knowledge and learned is diffused throughout a large geographic region due to trade.

Let's take a hypothetical to see how this works. Imagine, if you will, we're back to the ice age. There's a civilization that lives at the bottom of a flood basin. We can prove this because they left behind structures and a stone quarry. If we look closer, we can see how they live. Taking one family, a "modern" stone age family if you will, we see that they live in a rather advanced society. They have created large stone family dwellings, showing both a knowledge of load bearing walls and engineering principals allowing them to place stone ceilings on their homes. They haven't developed metal working, but they've advanced very far with the domestication of animals. We can see that they take care of refuse by disposing of excess with scavenger animals. They've trained small animals to do tasks, such as miniature wooly mammoths that can suck up dust on the floor. They have the wheel, and have managed to create human powered transport with it. We see that they have an excess of food production, so much so that gluttony seems to be a defining cultural aspect. This family of flint makers, we'll call them the "Flintstones", live like their post-industrial ancestors. We see them forming fraternal organizations, with names taken from local animals such as the water buffalo. Sadly, as the climate changes they suffer a catastrophic collapse. Melting glaciers flood their town, and nobody has a gay old time. (The only survivor, "Barney", eventually gives rise to the stories of Gilgamesh and Noah ten thousands years later.)

From the standpoint of archeological evidence, it would be possible for us not to find the city state of Bedrock. Would that mean that we would have lost an advanced civilization? Well, not really. Yes, we don't have a remaining artifact, such as a camera with a small bird inside, but we would see evidence of a large population explosion. We would see ideas and technology diffusing amongst other tribal groupings in the area. We could easily point to evidence showing that 14,000 years ago there was a population living in the region of close to a million.

So I guess the short answer is, as I mentioned, that the technological level of advancement would not be that great unless somehow the population was isolated from the rest of the world.

[Michael Redman]

How about the fossilized remains of a species even capable of such intelligence? Or even a line of fossils indicating the timely evolution of such a group? It's not just technical artifacts we're missing, it's candidates.

Once you have that, I would think the rest would be easy. We have fossilized evidence of feathers, and what some dinosaurs ate before they died. Unless they ran around naked and carried no tools, such ancient people, had they existed, would surely have been fossilized with some artifact from time to time.

[Wolfman]

fuelair and Gbob,

I think that you are failing to take into account the impact that tens or hundreds of millions of years could have on such artifacts. The examples you cite don't even fall in the category of being a million years old.

I guess the original question is somewhat ambiguous, in that it says only "pre-historic times", and does not set a limit on what that means. "Pre-historic" could easily be less than one million years ago; or it could be more than a hundred million years ago. And one's answer would differ tremendously based on that answer.

Since the original question cited the situation of the dinosaurs, I refer more to prehistoric societies which theoretically were contemporary with (or preceded) dinosaurs. And again, there is still the question of whether we are talking about a civilization that leaves remains that are both preserved and discovered due to random chance, or if we are talking about a civilization that specifically wants to leave its mark.

I guess I'd tend to turn the question around a little: if humans were to disappear entirely within the next 100 years, and we knew it was going to happen, what could we do to ensure that a future civilization (from our own planet, or another) would be able to find 'proof' of our civilization millions of years in the future? And what level of 'civilization' would we have to have reached in order to do so?

[Gbob]

Well, if we're looking at former species, and a time frame of million of years the answers are even more depressing.

Let's look at "if the human race all died tomorrow". Now, I have no idea how this would happen. There is no disease, no act of war, no change in climate that can really accomplish this. Even if a nearby star went nova and emitted a gamma bursts that cleansed the surface of the planet of organic matter, humanity would still survive (buried seed stock, stockpiles of food, etc etc). Given the significant advantage intelligence gives for survival, it doesn't seem likely that our ancestors would lose this trait even in the face of disaster. There's that great cliché that intelligent creatures find a way to destroy themselves, but destroying humanity is really, really, really hard if not impossible. I'm not saying it's not worth trying, it's just that you may not be able to do it.

But let us wave our hands and dismiss this fact. After all, we have a sample size of intelligent life of exactly one species today, so perhaps another form of intelligence may be possible. Unlike our simian ancestors, this life form could not deal with changes in climate. They were intelligent enough to have a city dwelling technology, but too dumb to figure out clothing or migration. What could we expect to see?

If you've ever had the chance to visit central America, I highly recommend visiting some of the ruins there. You can see how possible it is to "lose" a city. In just 500 years, there are numerous cities lost to the jungles. Over a million years? Even the mighty pyramids would vanish. Still, you would find the bones of those people long after. Remains fossilized, clutching proof of intelligence. Their bones would remain long after their cities had fallen.

If you had an iron age society, however, then you get even more artifacts. The example of seeing a fossilized skeleton holding a spear would be expected. Burial plots are fairly easy finds. It would be great for a an intelligent dinosaur society to save us the trouble and bury itself rather than the hope of a mudslide to produce a fossil. Our museums would be full of them.

If humanity vanished today you could tell our passing by our wastes. There are garbage dumps in Jersey where garbage will fail to break down because of lack of oxygen in the dumps. We would find plastics even millions of years from now. We would find metals in the bedrock that could not be produced naturally in such quantity.

I would sooner expect us to find my town of Bedrock before an intelligent dino society.

[blutoski]

Okay, so the thread title isn't great, but I couldn't think of a good one.

I was recently reading one of the Science of the Diskworld books in which is postulated (for no more than educational purposes) a race of intelligent dinosaur herders wandering across the plains some 66mya who, along with all traces of their existence, were wiped out when that big rock touched down in the gulf of Mexico.

It got me to thinking, how far advanced could any pre-historic, non human society have got before it would have left visible traces that we would have discovered by now? I don't have the necessary knowledge to speculate, I wondered if those who have might be able to?

Ironically, primitive civilizations can sometimes leave more and better evidence than more recent ones. The key isn't the level of advancement, but in the durability of the materials. Oldowan technology is made of rocks, and date as far back as 2.4 million years. This predates 'knapping flint' by millions of years, and is not even our species (Oldowan tools were probably made by H. habilis).

In comparison, the Huns left virtually nothing, as most of their posessions were organic (stoneware pots, wooden tools, hair or silk fabrics...) and they did not bury their dead with objects. We infer the size and importance of their settlements by locating post-holes, and assume that they supported tents or beam-roofs. We know more about their Germanic allies, who liked metal trinkets and cauldrons. As pointed out earlier, technically, these were prehistoric people, as they left us no writings. (Yes, yes, the Romans left us written testimony of their existence, so we can quibble about the meaning of 'prehistoric')

Alternatively, we can often identify settlements by what's left of their garbage piles - bones broken in a certain way can strongly imply tools, even if they're not actually found. Animal skeletons 'sorted' into distinct piles imply intelligence and purpose.

[andyandy]

ok, i have a question along similar lines....

given the relative scarcity of fossil remains from pre-historic times, what size population of species/sub species could remain undiscovered today?

It's rather vague, so i'll try to qualify it a little,

say if at some point along the evolutionary chain a sub population took on much taller frames than h sap sap norms - (let's say 8ft+) and that this sub population were around for 1000 years about 10,000 years ago, what size sub population would be necessary to be likely to discover fossil bone evidence of their existence?

[CapelDodger]

[quote=3point14;2441924It got me to thinking, how far advanced could any pre-historic, non human society have got before it would have left visible traces that we would have discovered by now? I don't have the necessary knowledge to speculate, I wondered if those who have might be able to?[/quote]
If a big rock had come hurtling down in 1700CE and done us in, would there be any evidence of human civilisation in 60my? I doubt it. If it happened now, though, there's definitely evidence. We haven't just scraped at the surface since the 18thCE, we've delved deep into hundreds of millions of years of geology. Future intelligent delvers will see the evidence, in dry wells and mined-out seams that defy any other geological explanation. No cheap energy for them. Plenty for us. Looks like we got to the buffet table first :) .

[CapelDodger]

say if at some point along the evolutionary chain a sub population took on much taller frames than h sap sap norms - (let's say 8ft+) and that this sub population were around for 1000 years about 10,000 years ago, what size sub population would be necessary to be likely to discover fossil bone evidence of their existence?
Over that period the bones would provide evidence, the happenstance of fossilisation is far out-weighed by burial practices.

[blutoski]

ok, i have a question along similar lines....

given the relative scarcity of fossil remains from pre-historic times, what size population of species/sub species could remain undiscovered today?

It's rather vague, so i'll try to qualify it a little,

say if at some point along the evolutionary chain a sub population took on much taller frames than h sap sap norms - (let's say 8ft+) and that this sub population were around for 1000 years about 10,000 years ago, what size sub population would be necessary to be likely to discover fossil bone evidence of their existence?

I don't think we can predict. Conditions play a critical role. A generalization: we know a lot about desert people. Not much about jungle people.

We have no physical specimens for huge populations that we know existed in Northern Europe prior to 0BCE. We know they were there, because of indirect knowledge (they made war on their neighbours, who did keep records, for example) and there must have been millions of them slogging through that muddy landscape for a hundred thousand years. On the other hand, one day we find twenty articulated Neandertal skeletons preserved in a nice dry cave in Spain from what must have been a tiny village.

Lady chance.

[blutoski]

I forgot to mention the anthropological benefits of bogs (http://www.qwantz.com/index.pl?comic=957).

[George152]

The only manmade objects that will last into the millions of years are pottery and glass.
Any previous civilisation would (if they had the technology) leave the same materials for future discovery

[blutoski]

The only manmade objects that will last into the millions of years are pottery and glass.
Any previous civilisation would (if they had the technology) leave the same materials for future discovery

Well, rocks, though. Don't forget about rocks. The Oldowan technology is just cobble-sized rocks, but we know they are technology, since they were modified for a purpose. If humans were wiped out thousands of years ago, aliens would still trip over those Venus statuettes, even a hundred million years from now, those'd still be intact.

And controlled fire. Firepits are easy to recognize. I'd be impressed if we found firepits from the Jurassic - if Dino was cooking dinner, that'd have huge ramifications.

The big challenge with primitive objects is that they can resemble naturally-forming objects. Glass also occurs naturally (an interesting recent find regarding egyptian glass ornaments is that some were mined, as opposed to manufactured) as does chipped stone.

[TriangleMan]

The only manmade objects that will last into the millions of years are pottery and glass.
Don't forget refined gold, platinum and other metals. Cut gemstones would also survive the ravages of time and show conclusive proof of an intelligent civilization.

[Amapola]

Don't forget refined gold, platinum and other metals. Cut gemstones would also survive the ravages of time and show conclusive proof of an intelligent civilization.

Now that's an interesting idea. Diamonds cut by dinosaurs! Can gemstones be dated somehow? If we found stones cut in a way not practiced by most cutters, how would we know they were really really old, and not just a hoax? Or would they be dated somehow by where they were found?

[3point14]

Interesting replies, thanks.

I wasn't thinking about any specific type of timescale when I asked the question. I suppose I could put it in another way, and ask when in pre-history such a non-human civilisation would have to have been, and still have escaped our attention by now.

[TriangleMan]

Now that's an interesting idea. Diamonds cut by dinosaurs! Can gemstones be dated somehow? If we found stones cut in a way not practiced by most cutters, how would we know they were really really old, and not just a hoax? Or would they be dated somehow by where they were found?
Hmmmm, I don't know. I don't think gems can be dated to the time that they were cut. Jewellers can give a minimum age for when the gem was cut based on the kinds of cutting marks left behind by use of certain technologies (this was how the Crystal Skull (http://skepdic.com/crystalskull.html) was shown to be a hoax), but that only applies to gems cut by humans.

[Big Al]

What about geostationary satellites? The atmosphere is so thin 22,000-odd miles out that they should orbit for a very long time. The Apollo moon equipment and debris should remain substanitially intact, too, with only infrequent micrometeoroid impacts to wear them away.

[Soapy Sam]

We should also bear in mind that the palaeontological / archaeological techniques of the future may be vastly better than what we have now.

[Correa Neto]

Pretty much what Soapy Sam wrote.

I would like to add a couple of things.

First, garbage. Civilizations produce a lot of it. I think the future overlords of this planet will be able to date specific periods of our civilization based on garbage layers that will be found at several locations cross the world. Tin beer cans period, aluminium beer can period, glass Coke bottle period, plastic Coke bottle period, disposable diapers period, and so on...

Second, the odds of remains preservation are not as low as some supposed. Its actually possible to preserve a whole city for hundreds of millions years. All it takes is the city being located at a sedimentary basin. Eventually it will be buried under hundreds or even thousands of meters of sediments. Millions of years later the basin's sedimentary sequences will be inverted and the preserved city exposed. I bet even the metamorphosed and sheared remains of buildings could eventually be recognized as artificial structures. And, at last but not least, remember Pompeii and Herculaneum.

ETA: Seismics! A city buried within a sedimentary basin could be identified during a seismic survey for oil, I think. Gravimetry, not sure, ground survey, maybe if its relatively shallow; aerial gravity survey would not work. I'm quite sure aeromagnetics are a no-go, ground EM methods maybe. Radiometric surveys, pretty much useless.

[Soapy Sam]

ETA: Seismics! A city buried within a sedimentary basin could be identified during a seismic survey for oil, I think. Gravimetry, not sure, ground survey, maybe if its relatively shallow; aerial gravity survey would not work. I'm quite sure aeromagnetics are a no-go, ground EM methods maybe. Radiometric surveys, pretty much useless.

Forgive my scepticism on this one. I've known 3-d seismic refraction surveys to miss whole mountains. Besides, I reckon anything buried deep enough to need a refraction survey will be fairly compressed.

Shallow reflection profiles and ground sonar are a far better bet I think. Also, marine research. Nonsense about Vedic spaceships aside, there really is a lot of continental shelf under water that used to be land. I expect we will find some interesting stuff in the continental seas in the near future.
Not pre-human, but surely prehistoric.

[Michael Redman]

I expect we will find some interesting stuff in the continental seas in the near future. Like Miami?

[Soapy Sam]

Like Miami?

Or indeed London.

[CapelDodger]

I think the future overlords of this planet will be able to date specific periods of our civilization based on garbage layers that will be found at several locations cross the world. Tin beer cans period, aluminium beer can period, glass Coke bottle period, plastic Coke bottle period, disposable diapers period, and so on...

Landfill layers are very accurately dated by newspapers. It's the common practice, I've been told by people that actually do it. Wadded paper takes forever to rot, and nothing much eats the ink.

[Beady]

I guess the original question is somewhat ambiguous, in that it says only "pre-historic times", and does not set a limit on what that means. "Pre-historic" could easily be less than one million years ago; or it could be more than a hundred million years ago.

Less than that. Alaskan pre-history, for example, can be said to be only a few hundred years ago, perhaps less.

[Correa Neto]

Forgive my scepticism on this one. I've known 3-d seismic refraction surveys to miss whole mountains. Besides, I reckon anything buried deep enough to need a refraction survey will be fairly compressed.

Shallow reflection profiles and ground sonar are a far better bet I think. Also, marine research. Nonsense about Vedic spaceships aside, there really is a lot of continental shelf under water that used to be land. I expect we will find some interesting stuff in the continental seas in the near future.
Not pre-human, but surely prehistoric.
Yeah, I guess you may be right. Surely shallow stuff would be easier to locate. GPR could work, eventually, depending on the depth.

But I am not sure on how compressed say, a modern 10 story building would be when buried by sediments. OK, buildings are mostly made of empty space, but still... I guess it would depend on how it was buried. Wave action would probably affect the buildings at a subsiding sea shore, and several would become nothing but a pile of rubble. Maybe the inner parts of the city would be preserved from wave erosion by the obstacles to wave action created by the outer buildings. A similar fate would await a city being buried by fluvial sediments (specially at braided systems).

I guess desertic environments with the advance of sand dunes or laccustrine/laggonal enviroments with little energy would have better odds of preservation. Aniway, the empty spaces would have to be filled with something (sediments or water) to counter the effects of a thick sediment overburden.

But now I do wonder how reflective would be a "city horizon", specially if compacted. It would be a heterogeneous mass of concrete, steel, hardened clay, asphalt, plastics, aluminium, etc.

Aniway, assuming present-day tech can detect such structures, I guess regional surveys would have better odds of showing them. Detailed surveys, specially those concentrated at structural traps, would have less chances. Tectonic activity could decrease the odds of preservation.

Oh, yes, I do expect interesting stuff to be found at the continental shelves. Not Killik-grade stuff, of course...