prehnite-pumpellyite facies
Quick Summary
The prehnite-pumpellyite facies is a division of metamorphic rocks formed under the lowest temperatures and pressures of regional metamorphism, bridging the gap between diagenesis and the greenschist facies. It is particularly well-developed in graywacke-type sediments.12
Minerals characteristic of this facies include prehnite and pumpellyite, which replace zeolite minerals found in the zeolite facies. These are, in turn, replaced by epidote minerals in the greenschist facies or by lawsonite and pyroxenes in the blueschist facies. Other common minerals are quartz, albite, chlorite, stilpnomelane, muscovite, and actinolite. This facies is often described from younger mountain ranges along the Pacific margin.2
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
