system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how can a layer of metamorphic rocks be on top of a layer of sedimentary rocks? Shouldn't the deepest layer have higher pressure and temperature?
gpt
You are absolutely right, the deeper a layer gets buried, the higher pressure and temperature it is subjected to. 


However, there are two ways to explain your question. Compressive tectonic forces can fold or fault rock layers which would place metamorphic rocks above sedimentary rocks. 

A thrust fault is a type of fault that pushes deeper, older rocks over younger rocks. Imagine pushing two pieces of paper together on a flat surface. One would slide on top of the other, which is exactly what happens in a thrust fault. There are places in Canada where very old granite has been pushed up on top of young sedimentary rocks via thrust faulting. For the folding example, think about a tablecloth pushed over a smooth table, it would bunch up in a series of small folds. The same thing happens with rock layers. Sometimes rock layers get folded so much they become overturned, which means a "lower" layer would be on top of an "upper" layer.