Which geological processes will destroy plastic?

Question

The geological record at the end of the Anthropocene will undoubtedly contain large volumes of plastic. However, some geological processes will completely destroy plastic (e.g. magmatic or chemical processes). I assume that sedimentary rocks will contain plastic pellets at the least and that igneous rocks will not. Which geological processes that create metamorphic rock will be able to completely destroy plastic molecules?

Answer 1

The main metamorphic processes are regional, contact/thermal, dynamic, shock, & hydrothermal. All of these will degrade the plastic, but unless the heat or pressure gets the plastic to a melting (or reacting) temperature they shouldn't fully destroy it.