I was looking at some rock formations the other day, wondering about the mineral composition that made them and how they formed. That slowly wandered over to the realm of landfills, and I wondered what would happen over time. If a landfill were to get subducted and melted, are there any decent wags as to what the contents of a typical landfill might crystallize into after melting? I know it’s a rather broad question, but it’s piqued my interest.
Coal, probably. Most common waste materials, such as wood, paper, plastic, cloth, etc. are complex hydrocarbons, and when those break down the hydrogen will react with oxygen to form water molecules, leaving the carbon behind.
Neat.
Er, naturally I meant those materials are organic compounds. Sorry about that, English is my second language and chemistry was plenty difficult enough to grasp in one language.
They will likely be mined for resources by future generations.
I’d like to hope they would all become botanic gardens like this one in my neighborhood.
The AOL-CD line will be useful to future geologists for dating purposes.
I imagine that within a century or two, presuming we have not obliterated ourselves as a species, we will have advanced our recycling and reclamation methods to the point that it will be big business to open up and clean out landfills for valuable metals and other resources.
The most common single thing in a modern sanitary landfill is dirt. Lots and lots of dirt. They have to truck in huge quantities of dirt to cover stuff up. There’s so much dirt in them that some places are now digging it up and selling it. (They dig up a small area to a large depth, move the trash off, cover that with a thin layer after sifting out dirt for sale. Must sell it to other landfills. Has to be pretty hazardous.)
So, whatever the local cheap dirt would turn into after being squashed and heated plus intrusions.
And millennia? Millennia? Nothing much happens in a landfill in that short of time.