Besides using coal for fuel, what are some other uses of other organic sedimentary rock?
If you happen to don't forget reef-rock as an healthy rock, then a unexpected cooling of the environment would kill the reef and stop further development. Coal, on the other hand, consists of carbon of healthy (quite often plant) fabric. It's deposited after which buried, compacted, and grew to become to nearly pure carbon. If a forest is exhumed from water before burial (as a result of uplift or reducing of sea level it's going to not end up buried, therefore will not be turned to coal.
