[ahakki]

Only if you assume that the supposed advanced ancient civilization oxidized large amounts of fossil hydrocarbon.

[masklinn]

So what you're saying is there was a massive technologically advanced civilisation which didn't build buildings, didn't carve stone, didn't mine or refine metals, didn't deforest, didn't farm, and didn't use oil?

[noslenwerdna]

But there are other chemicals that a civilization might produce that are also visible in the geological record. Fertilizers would also leave a mark.

[stuxnet]

https://en.wikipedia.org/wiki/Terra_preta

> Terra preta soils are found mainly in the Brazilian Amazon, where Sombroek et al. estimate that they cover at least 0.1–0.3%, or 6,300 to 18,900 square kilometres (2,400 to 7,300 sq mi) of low forested Amazonia; but others estimate this surface at 10.0% or more (twice the area of Great Britain).