I know that a metamorphic rocks mineral composition depends on the composition of the origional rock and the temperature and pressure during metamorphism (metamorphic grade). However I am still unclear on how geologist's determine metamorphic grade. How is this done?

-- Angela Barrett (Pangela_5@yahoo.com), November 14, 2002

Answers

By knowing what mineral is in the rock, they will know the metamorphic grade because there have been many experimental studies and much research and they found out at what temperatures each mineral begins to metamorphose.

-- David Michael Ahmad (ahmad@oswego.edu), November 18, 2002.