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tomtom5858 t1_jb6d12g wrote

Reply to comment by raducu123 in What happens at the end of a subduction zone? When the entire plate subducts? by kittens0423

>Why don't they just melt?

Pressure is too high to let them. That said, "melt" isn't a well defined term in conditions like this; at what point has ice cream melted?

>Are there fossils buried in the mantle?

Yep. If fossiliferous rocks are subducted, the fossils will be buried in the mantle until eventually, those fossils are somehow transformed beyond being recognizable as fossils (i.e. they're mixed enough, melted or not).

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forams__galorams t1_jbc9f59 wrote

> Yep. If fossiliferous rocks are subducted, the fossils will be buried in the mantle until eventually, those fossils are somehow transformed beyond being recognizable as fossils (i.e. they're mixed enough, melted or not).

Your use of ‘eventually’ is kinda misleading here. Any fossiliferous rocks would be at the top of a subducting slab and so if they didn’t get scraped off onto the overriding plate they would already be sheared upon entering the mantle; not to mention right at the slab-mantle interface where it won’t be long at all before the heat finishes them off.

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