If we can dig and mine up coal, does that mean that it was once a tree that burned down?

Question

If we can dig and mine up coal, does that mean that it was once a tree that burned down?

In: 245

Answer 1

Coal is not the same thing as charcoal.

Dead plants which are prevented from decaying by acidic/oxygen-depleted wetland waters become peat. Peat, when buried, is compressed into coal after millions of years of heat and pressure underground (which drives off the volatiles, leaving only the carbon).

Coal used to be trees (or other plants), but they didn’t burn down; they were submerged, then buried.

There *is* such a thing as fossilized charcoal caused by ancient forest fires, but that’s different. It’s called [fusain](https://en.wikipedia.org/wiki/Fusain), and doesn’t generally form massive seams like coal does (as it’s created by individual events instead of a wetland building up a thick layer of buried plant matter over hundreds/thousands of years).