1. Seismological Laboratory, California Institute of Technology, Pasadena, Calif. USA;2. Research School of Earth Sciences, Australian National University, Canberra, A.C.T. Australia
Abstract:
Phase behaviors of albite, jadeite and nepheline have been studied in the diamond-anvil press employing YAG laser heating from about 100 to 280 kbar and at about 1000°C. Incorporating earlier work, the sequences of phase transformations with increasing pressure are as follows:
where the percentages are the decreases in zero-pressure volume from one to the other. Both NaAlSi3O8 hollandite and NaAlSiO4 (CaFe2O4-type) are new sodium aluminosilicates. The latter is the most likely host for sodium in the earth's lower mantle. High-pressure phases or phase assemblages revealed in albite and jadeite by static experiments are poorly defined by shock-wave studies of albitite and jadeite to about 900 and 1200 kbar respectively.
