The topic of landfill sites seems interesting. What do they end up containing in the long run, after all the other material has been eaten or biodegraded? If

The topic of landfill sites seems interesting. What do they end up containing in the long run, after all the other material has been eaten or biodegraded? If we come back to a landfill site in two hundred years time is it going to contain a particular type of mineral? Will it just be trash still? On what kinds of timescales does it metamorphose significantly, and into what kinds of material?