Ringwoodite growth rates from olivine with ~75ppmw H2O: Metastable olivine must be nearly anhydrous to exist in the mantle transition zone

Wyatt L. Du Frane, Thomas G. Sharp, Jed L. Mosenfelder, Kurt Leinenweber

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23 Scopus citations


It has been previously demonstrated that as little as 300ppmw H2O increases wadsleyite and ringwoodite growth rates to magnitudes that are inconsistent with the metastable olivine hypothesis. To further test this hypothesis, we present new ringwoodite growth rate measurements from olivine with ~75ppmw H2O at 18GPa and 700, 900, and 1100°C. These growth rates are nearly identical to those from olivine with ~300ppmw H2O, and significantly higher than those from nominally anhydrous olivine. We infer that transformation of olivine with 75-300ppmw H2O is primarily enhanced by hydrolytic weakening of reaction rims, which reduces the elastic strain-energy barrier to growth. We present a new method for fitting non-linear nominally anhydrous data, to demonstrate that reduction of growth rates by elastic strain energy is an additional requirement for metastable olivine. Based on previous thermokinetic modeling, these enhanced growth rates are inconsistent with the persistence of metastable olivine wedges into the mantle transition zone. Metastable persistence of olivine into the mantle transition-zone would therefore require <75ppmw H2O.

Original languageEnglish (US)
Pages (from-to)1-10
Number of pages10
JournalPhysics of the Earth and Planetary Interiors
StatePublished - Jun 2013

Bibliographical note

Funding Information:
We thank T. Diedrich and G. Moore for help with experiments conducted at the ASU OmniPressure lab; K. Roggensack for assistance with sample sectioning; E. Soignard and R. Tricky for assistance with Raman; and T. Tenner, A. Withers, and M. Hirschmann for providing their assistance with SIMS calibration and measurements on the Cameca 6f at ASU. We thank T. Kubo and D. Rubie for their reviews and comments that helped us significantly improve this manuscript. SIMS data were obtained at the ASU National SIMS Facility, supported by NSF EAR-0622775 to R. Hervig and P.Williams. SIMS data obtained at the Center for Microanalysis at Caltech were partially supported by the Gordon and Betty Moore Foundation. We acknowledge the LeRoy-Eyring Center for Solid State Science for access to Raman and SEM instrumentation. This work was supported by NSF EAR-0838159 to T. Sharp and NSF EAR-0947956 to G. Rossman. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.


  • Growth rates
  • Hydrogen
  • Mantle
  • Olivine
  • Ringwoodite
  • Subduction
  • Transformation Kinetics


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