andrewducker | Question for the floor

I think you're going to need to state environmental assumptions. Destroyed by a volcano ≠ buried in permafrost.

Plus local soil chemistry makes a huge difference, though in complicated ways - acidic soils tend to destroy things like bone an awful lot faster than neutral / alkaline. And waterlogged acidic soils are lethal for metals, but if they're sufficiently wet and acid (eg peat bogs) they preserve organics really well.

If you actually wanted to research the topic, I'd recommend finding a basic archaeological textbook as a starting place. Things like phosphate residues and stone tools last a very long time.

Without major cataclysm, I'd say that human influence on the planet would be visible (or at least easily found or inferred) for tens of thousands of years (at least!). Stone buildings may only survive for a couple of thousand years (unless they're exceptional, such as large pyramids), but there are such huge works of engineering that I can't see being worn down for much longer (reclaimed land, dams, huge skyscrapers).

Plus, plastics and other pure, non-corroding substances should persist.

Oldest known ceramic...

http://en.wikipedia.org/wiki/Venus_of_Doln%C3%AD_V%C4%9Bstonice

Oldest known carving...

http://en.wikipedia.org/wiki/Venus_of_Willendorf

And considering their condition, it would appear that simple stuff humans can make could last a lot longer than 30,000 years.

Which doesn't answer your question, but perhaps fossil trackways do...

http://en.wikipedia.org/wiki/Fossil_trackway

So ceramics could retain their shape for millions of years, yes?

If you include tools pretty fucking long. In Ethiopia they've found tools more than two million years old. And if you want more civilized than that the Pyramids date back to 2060 B.C. or so.

The Lascaux cave drawings are supposed be something like 17,000 years old.

2-17,000 years clearly isn't long enough for all traces to vanish. I'm curious as to whether 150,000 years would be.

Not heard the Ethiopia thing. Got a link for it?

Oh, and did you notice you made the links page today?

I saw and thank you!

I've been distracted watching the people at metaquotes and sf_drama calling me a dudebro all day or I would have commented!

Here's a link to the tools thing

http://www.archaeology.org/9703/newsbriefs/tools.html

I only know about the tools because we are fairly close to the France cave drawings and people always ask if those are the oldest human remnants and then some smart alec always responds "No! Think of Ethiopia!"

Fascinating. More the tools of a stone age tribe than of a Mesopotamian-style civilisation, but definitely worth knowing about. Thanks!

What's going on over at metaquotes/sf_drama???

They've both decided I'm a "dudebro" and a "fratboy" because of my post a couple days ago where I joked that most insults are racist/sexist/ableist etc...

Then I made the mistake of trying to blow their minds by pointing out that I spend most of my day writing for gay and transgendered community and they went apeshit (though they had already gone apeshit on me anyway, so I'm mostly just becoming amused at their assumption that I'm some hypermasculine defender of the patriarchy."

My favorite part is that they took me seriously when I said that using the word "douche" is "hygienist."

http://community.livejournal.com/metaquotes/7503111.html

http://community.livejournal.com/sf_drama/3172226.html

Crikey.

That appears to be two mobs of angry stupid people looking for things to get excitedly self-righteous about.

It is amusing me to no end.

I've now started telling them that their taunts are turning me on and begging them to 'whip me, beat me, make me disrespect the plight of the Native Americans."

So I see.

It's like they've cargo-culted the techniques of the various -fail 'disputes' (complete with screencaps[1]. Why?) and are throwing them at anything that looks like a target.

I really am quite confused by it all.

[1] Because spidering is hard and/or a tool of the patriarchy, I guess.

Confusing to me too - but I have almost no work today yet needed to be in front of the computer in case work came in - and trying to mess with their minds has seriously helped pass the time.

I've also had 15 people add me as friends today.

The Internet is a weird fucking place.

I would be one of those fifteen...

I don't think I know any "Native Americans". Lots of (American) Indians, yes -- most of whom sing at least some pre-white-conquestn Songs and have some knowledge of their native language.

I think it would depend on the conditions and the history. Some physical conditions preserve features much better than others. History has a role to play too. Lots of Roman cities are identifiable because post-Roman people took over their sites and built on top of them, preserving them as layers of different cities, whereas more of the Archaic Greek stuff was just destroyed in their Dark Age. Ish.

Also what you define as traces. Do you want to be able to describe aspects of the day to day lives of individuals or do you just want to be able to say somebody who was civilised but different from what is here now used to live here?

I'd like to be able to show that there was once a city on a particular spot. That's about it. The discussion started elsewhere about whether a civilisation from the last interglacial (110,000 years ago) would leave any traces that we could actually spot.

Hmm.

A civilization from the last ice age might actually be harder to identify than one from the interglacial. Consider that during ice ages the sea levels recede in some areas (ice sheets push down on the underlying strata, causing non-covered areas of continental shelves to rise; also, less water in the oceans). So you'd expect the most fertile soil to be found in the low countries such as Doggerland or what is now the Arabian gulf -- where they'll be inundated when the ice age ends.

Also: if they primarily use wood and metal, rather than stone implements, and baked clay for buildings, they'll disappear a lot faster once they're underwater.

I guess that inundation could be the cause of all of the flood stories that occur in so many myths and legends (I imagine that's a quite common thought amongst people studying such things).
I wonder how many likely candidate areas have been searched under water for ancient stone settlements. Maybe not the easiest things to find or getting funding to look for.

I think if it were under the ice there would be nothing left. The glaciers would strip everything back to what archaeologists call the natural or down to bare rock.

If it's not under the ice there should be a good chance of anything big enough to be a city leaving some traces tho' to my knowledge non have been found.

Well, stone stuff lasts a very long time, so if your hypothetical civilisation used stone then it'd be a lot easier to find than if it was based on wooden or clay brick buildings.

Skara Brae, for example is about 5000 years old and pretty much completely preserved, whereas most archaeology from that era is stains in the soil which are generally to be the remains of post holes, and rusty masses which can be scanned to prove they were once tools...

That's the thing. I was discussing whether a civilisation from the last interglacial (say 110,000 years) would leave any traces that were detectable nowadays.

I was thinking pottery (which seems to last a very long time), but I can't see how long that that lasts.

Stone, obviously, would leave loads of traces.

Iron would leave nothing at all.

How long does bronze last for?

Well, glaciation is a game-changer there. The Canadian Shield is as inarable as it is today because the glaciers moved much of the topsoil south; this would badly disrupt stratigraphy and probably crush a lot of artifacts beyond recognition. Anything that went down to the bedrock would show, but I don't know how many Babylonian-tech structures would have foundations that deep.

-- Steve would need more information (and a refresher course on archeology) before making any detailed suggestions, though.

We have pottery that has survived from the earliest pottery making civilisations. Heck, before that we've got wooden plates and bowls made by Mesolithic hunter-gatherers.

So yes, stuff survives.

Except, as I just said in a comment below, in areas that have been subject to glaciation.

If there was a civilisation that was located only in areas that were covered by ice, then I would not expect to see any traces of their survival.

Which grants lots of room to crazies to argue that this is what happened to Atlantis.

Pottery would take fossilisation much better than, say, a dinosaur egg, so the answer has to be in the hundreds of millions of years. Most of the objects wouldn't fossilise, of course, but I do wonder about some of the North Sea sites (unless we fuck them all up with repeated dredging).

How long would pottery last without fossilisation?

Well, we have physical remains from every civilisation we know of, and right back beyond civilisation to stone age tools preserved alongside human fossils. So there's a continuous spectrum with no well-defined upper limit. Stuff gets covered over by rubbish and soil in a very predictable way - ground levels change all the time - so even if I left a pot in the middle of a grassy field, compelely exposed, it'd get incorporated into the soil and could last indefinitely.

Having said which, if I left it near a cat, about 3 minutes.

Assuming the civilisation had the technical know-how to fire the pottery at high (1000 degrees C+) temperatures, and access to the right sort of clay, pottery would basically last as long as stone. They would need charcoal for this and a properly built kiln though. Most, if not all early pottery is earthernware fired at a lower temperature though so I don't think that is at all likely for an interglacial society.

As for how long eartherware ceramics would last, I guess a soft sandstone would be comparable in terms of erosion-resistance. If it was buried, strong temperature variations would be the main culprit for breaking it down (cracking from expanding and contracting, especially in damp conditions when water could seep into cracks) so it would depend where in the world the remains were.

/pottery and soil science geekery

You'd need something to scrape the land clean, because tools/etc will last... well. As long as we know of there being homo sapiens and even earlier hominid species around.

There's no reason to s uppose that in millions of years time, there won't still be artefacts of human civilisations being dug up.

So what you'd need to obliterate the human record would be something like a glaciation event, to scrape the land clean and wind up depositing almost everything in the deep oceans.

There is no evidence of really ancient human fossil remains in those parts of the world that have been exposed to repeated glacial action.

It gets less and less likely that traces would be found, but if conditions are right for fossilisation, the probably of detection never really gets to zero in less than hundreds of million years. Oldest vertebrate fossils from 450 million years ago "are rare and fragmentary"

A really clever take on this popped up on RPGnet. Someone wondered if there had been a dinosaur civilisation, if we'd be able to spot it. And sure, many materials would have broken down.

But if the dinos had embedded gemstones in their teeth, we'd spot that. So essentially, if we had tyrannosaur rappers, we'd know.

There might be motherlodes found from far distant past civilisations - a garbage dump, say a square kilometre wide and 10s of meters thick - might make an interesting fossil bed. The plastics would decay back to carbon dust, but would the metal bits keep their shape? There'd be glass, ceramics and things made from durable alloys in there.

Archaeologists learn a lot from middens which are much the same thing.

Edited 2011-02-12 00:11 (UTC)

That is very neat.

Clearly, if we found a cache of diamonds in a place where they wouldn't normally be found, that would be an indication of something going on, for instance.

There are archaeological finds of Australian aborigine stone tools dated to 50,000 years ago. Aborigine oral tradition also includes references to animals extinct since that time. That suggests that a continuing culture is capable of maintaining knowledge for a very long time.

What a fascinating question and set of answers. I'm going to be thinking of dinosaur rappers with a space program now.

Yeah, I got some fascinating thoughts there!

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