(1) Plagioclase is commonly variably replaced by aluminous prehnite, which indicates temperatures below 400°C.(2) It likely exists as a hydrothermal alteration product of aluminous materials.(3) Import tonnage of aluminous cement is small, however levels did increase by more than 33% to 41,137 metric tons.(4) Mafic and ultramafic rocks predominate, although a few examples of metasedimentary rocks are known, including aluminous lithologies.(5) Associated units are sillimanite-bearing aluminous metasediments, quartzites, and arnphibolites.
