forming fossil fuels requires deposition and burial of decaying vegetation
fossil is remains. fossil_fuel_generation is geologic_process. pigmentation is deposition. decay is natural_process. physical_vapor_deposition is thin_film_vacuum_deposition. fossil is petrification_of_living_being. physical_vapor_deposition is microfabrication. decomposition is decay. fossil_fuel_generation is not geologic_process.