We just visited Herculaneum and saw several examples of carbonized wood in the ruins. The guide explained that most wood was incinerated entirely, but in places where there was not much oxygen, the wood just turned to charcoal. But now I think about it, I’m curious about “places that there was not much oxygen.” What does explain the various spots where there are things like charcoal shutters, shelves, or doors? Where would there be low oxygen?
Places that caught on fire a little later perhaps after the first fires burned through the available O2?
The high temperature (450c) and the almost instant encasement by ash, excluded oxygen entirely.
Volcanic gases (CO2, H2S, SO2, etc.) may have also displaced atmospheric oxygen for a prolonged period, allowing time for slower buildup of ash.
There’s a whole library of ancient scrolls there, probably containing some lost ancient literature. But they’ve all been carbonized as they sit rolled up in pigeonholes. But they tend to collapse into a pile of ashes is moved. So scientists are trying to figure out a way of reading them without destroying them. So far, only occasional letters & words can be recovered.
Pretty soon here we’ll be able to observe this directly at Naples. We can see how it happens then.