In Situ Observation of the Formation of 10 Å Phase from Talc + H2O at Mantle Pressures and Temperatures
Nicholas J. Chinnery,
1*
Alison R. Pawley,
1
Simon M. Clark
2
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 + H2O to be observed in situ in a multianvil apparatus with
synchrotron radiation. The reaction talc + H2O = 10 angstrom phase was observed within 20 minutes at 6 gigapascals and
500°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.
1 Department of Earth Sciences,
University of Manchester, Oxford Road, Manchester M13 9PL, UK.
2 Daresbury Laboratory, Daresbury,
Warrington, Cheshire WA4 4AD, UK.
*
Present address: Daresbury Laboratory, Daresbury, Warrington,
Cheshire WA4 4AD, UK.
To whom correspondence should be addressed. E-mail:
alison.pawley{at}man.ac.uk
