Metamorphic series include the Barrovian and Buchan series of
metamorphic rocks.
George Barrow was a geologist in Scotland who discovered the Barrovian series.[1] These are also called metamorphic facies series. A
metamorphic facies series is a sequence of metamorphic facies which plot in a temperature-pressure diagram along a line, and this line represents a certain geothermal gradient. They are not the same as
metamorphic zones, as these are defined as a region on a geological map where the pressure-temperature conditions for an
index mineral (a mineral that indicates the approximate metamorphic grade of a rock), were appropriate for these minerals to form.[2][3]