In situ observation of the formation of 10 A phase from talc + H(2)O at mantle pressures and temperatures
Development of an x-ray-transparent capsule that is suitable for water-saturated experiments has allowed the high-pressure and high-temperature synthesis of 10 angstrom phase from talc + H(2)O to be observed in situ in a multianvil apparatus with synchrotron radiation. The reaction talc + H(2)O = 10 angstrom phase was observed within 20 minutes at 6 gigapascals and 500 degrees C. The higher pressure vapor-absent reaction talc = 10 angstrom phase + enstatite + coesite was also observed. The 10 angstrom phase is therefore a good candidate for transporting water into Earth's mantle at subduction zones. The in situ technique may allow the hydration of other high-pressure mantle phases to be observed under dynamic conditions.
Chinnery
NJ
Department of Earth Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK. Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, UK.
Pawley
AR
Clark
SM