…that some sort of intelligent civilization existed on Earth 100 million years ago? I mean…in 100 million years, EVERYTHING (except fossils) would be gone wouldn’t they? Including full blown cities?
The general idea is that some physical remnants would still exist.
Rock quarries, arrowheads, foundation stones, etc.
It isn’t absolutely impossible – relatively few things are – but the likelihood seems to dwindle to unobservable levels.
The fact that copper was so incredibly plentiful on Cyprus, for instance, very strongly suggests that no one, ever, had been interested in mining for it. Same for Californian and Australian gold.
(I do not know how long it takes geological processes to replenish rich copper and gold veins. Is 100,000,000 years enough?)
But suppose the civilization from that time doesn’t value copper or gold. They could have mined all of the existing iridium and that’s why we don’t have any now, couldn’t they?
I think it is unlikely that a society would advance to the point of using iridium without first discovering and using materials that are easier to obtain and turn into some desired product.
If they were truly intelligent and used biodegradable materials for all their construction, sure. Maybe we should try that. No shortage of jobs when you have to rebuild the roads and bridges every six months.
More seriously, I’m pretty sure that 100 million years is plenty of time to eradicate the signs of any type of civilization, at least to the limits of our ability to find them. It’s not necessary for arrowheads or whatever to decompose. All you need is a supervolcano to cover everything with a deep layer of lava.
An earlier related thread: Have we made a visible dent in the fossil record? there are many clues that we’d leave behind as incontrovertible evidence of a global, intelligent civilization even 100 million years from now.
A very small intelligent civilization would leave much less of a record. If humans had died out in 2000BC, there would be many fewer traces left 100 million years later.
As I mentioned in the earlier thread, The Earth After Us" is a good book on what evidence of intelligent life would remain 100 million years from now.
But wouldn’t ALL life be affected one way or the other? What kind of supervolcano could annihilate an advanced civilization without a trace, and not take out other lifeforms, or allowed other lifeforms to flourish? Even when the dinosaurs died off, there’s evidence of other species being affected . . . either dying off or flourishing. What kind of devastation could have no effect on any other species?
The aftermath of hydroelectric dams will remain for nearly the life of the planet unless they’re all sucked into subduction zones.
When all the Antarctic and Greenland ice melts we’ll be able to check out those dinosaur cities.
I wasn’t talking about a worldwide civilization made largely of steel, like today. The OP just asked about “some sort of intelligent civilization.” It could have been like some American Indian tribes, with no permanent structures, and localized. It could have died out from disease or whatever, long before the lava buried all evidence of it. And the volcano could have been the oozing type (like in Hawaii) rather than the explosive type, and only affected a relatively small portion of the globe.
I think that much of Idaho and eastern Washington was buried under a big lava flow. It doesn’t have to be a worldwide catastrophe.
How long does it take for ore bodies to reform?
Somewhat yes. A lot of the hydrothermal and placer deposits are much younger than that. Most primary sources are older than that, but not necessarily - some layered intrusions were still being emplaced 60Ma.
However…
The idea of “a civilization … with no permanent structures” is an oxymoron. Cities are part of the *definition *of civilization.
It is *theoretically *possible that some intelligent culture developed 100 Ma. and vanished without a trace. But not a civilization, no. Hell, I’d say not even stone tool-using culture. We find plenty of fossils from that far back, we’d find traces of tools.
We dig *below *thick layers of lava all the time.
I’m not familiar with the term Ma. In context, it means “million years ago.” What’s the derivation?
A different thought: we have fossilized skeletal bits of animals from 100 million years ago. Would it be possible to tell from the skeletons themselves if the entities were intelligent and civilized? e.g., trephination holes, piercings, cuts indicating weapon use, even such things as minor deformations indicating jewelry use?
Of course, sure, there’s no guarantee that we ever dig up the right skeletons, but if we did, wouldn’t “civilized” behaviors be detected? (How many of us have fillings in our teeth; will our fossils retain evidence of this 100 million years from today?)
It’s the SI prefix for “Million years” from the Latin megaannus [snerk]. In geological/palaeontological contexts, the “ago” is usually implicit.
“Possible”, yes - probable, no. Most fossil remains are fragmentary and this kind of thing would get lost in that process. But we do find whole corpses, hell, even dinosaur skin and eggs, occasionally.
Many of us Westerners do, I think, and yes, they definitely would be detectable. If we knew to look for them, that is. Teeth usually are the best parts to fossilize, and teeth with metal in them would be very easy to find, given the metals used for fillings.
But the kind of culture that’s filling teeth is the kind of culture that would leave lots of other traces, IMO.
Reminds me of a B.C. comic strip with one caveman is making a cave wall drawing of a the shuttle craft while another looks on. The caption says, “One day this will put some poor archeologist into a mental institution.”
Dale Sams, please make your thread titles descriptive. I’ve edited it so people will know what you’re talking about from the forum screen.
Thankee.
I think that Occam’s Razor has to be applied to questions like this. The options are either that there were no large civilizations 100M years ago, or that there were but that somehow it vanished without leaving any traces whatsoever.
The burden of proof is on the latter option, IMHO.
Big dam projects will have long-lasting effects over the scale of human lifetimes, but the hydrological processes they impact are fairly ephemeral when viewed over longer periods of geologic time.
Plus the age of the deposits themselves are less important than how long they’ve been exposed at or near the surface. The amount of ore that’s close enough to the surface to be recoverable is a pretty small amount of the total in the crust. Assuming a civilization rises, spends a few millenia mining all the valuable minerals that are near the surface and then vanishes, it’ll only take a few million years for tectonics and erosion and re-deposition to do their thing and bring more of the deeper deposits up to where they’re recoverable for the next civilization.
100 million years ago areas which are now underwater could have been surface landmasses. Assuming a small civilization (>10 million people or whatever) clustered relatively close together in an area which is now underneath one of the world’s oceans, there would be almost no way that scientists could tell if such a race existed or not.
Or such a race ould have developed in an area where there has been extensive volcanic activity (such as the Siberian or the Deccan Traps) and the remains of such a civilization could be buried underneath.