Returning to nature is relative. The presence of long-chain petrochemicals in layers where they don't belong, would last for millions of years. And is evidence of that asphalt road.
Yeah, but you'd only see that in sedimenting areas there were uplifted and then weathered; like orogenized river deltas. After that, you'd need to have a lot of samples in the sediment so that there'd be enough exposed rock to care to look at all. Then you'd need enough sample in the rock to detect above background noise. Then you'd need to conclusively explain away any natural causes for the presence of the asphalt, which is naturally occurring anyway.
I'm not saying it's impossible, but it would take a lot of luck.
Yes but considering the total length of paved roads in the world, often using asphalt, how they stretch terrain from coast to coast, on all inhabited continents, that some of it will pass areas that will be uplifted and brought to daylight - I see it as inevitable. It might need a trained eye to see, but it would be there.
Maybe. The surface area of all the roads in the US is ~25k mi2. Which is ~0.6% of the surface area of the whole US. And the US is a pretty advanced country in terms of road density and variety. I think we can say that the total global road density is likely less than even that. Now sure, road density isn't randomly distributed across the surface of the Earth. But future people will still need to get lucky just to see roads at all.
