[DFHippie]

I'm curious about this. We certainly won't get any more coal, but a whole lot of carbon gets subducted into the mantle regularly. Some gets turned into diamonds. Some gets blown out of volcanoes. Is the oil we pump out of the ground produced directly in the continental crust or is it generated from some of this carbon subducted with oceanic crust that has been transformed by some process and then made its way back into continental crust?

I'm lazy, so I'm hoping some geologist will stop by and educate me.