grade, metamorphic pyroxene or olivine. Thus, metamorphic assemblages of ultramafic rocks containing anthophyllite are indicative of at least greenschist facies metamorphism in the presence of carbon dioxide bearing metamorphic fluids.

The typical metamorphic assemblage reactions for low-magnesian (<25% MgO) and high-magnesian (>25% MgO) ultramafic rocks are;

* Olivine + Tremolite + Talc -> Olivine + Tremolite + Anthophyllite (low MgO, >550 °C, XCO2 <0.6)
* Talc + Tremolite

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