A rock originally formed by the deposition of sediments that has subsequently undergone metamorphism. Geologists study these rocks to understand the original depositional environment before tectonic forces altered their mineralogy and texture. Common examples include quartzite formed from sandstone, and slate formed from shale.
Heard on the job
The orebody is hosted in a sequence of folded metasediments, mostly phyllite and quartzite.
Insider tip
The prefix meta simply indicates the metamorphic history, so you will often hear terms like metagraywacke or metashale to be more specific.