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Contributions to Mineralogy and Petrology

, Volume 164, Issue 6, pp 1073–1076 | Cite as

Reply to ‘Comment on “The beginnings of hydrous mantle wedge melting” by Till et al.’ by Stalder

  • Christy B. Till
  • Timothy L. Grove
  • Anthony C. Withers
Reply

Abstract

The comment of Stalder raises three main concerns regarding the interpretation of the experiments presented by Till et al. (2012): (1) our inability to uniquely distinguish between high-pressure hydrous silicate melt and solute-rich aqueous fluid leads to the incorrect interpretation of phase relations, (2) the temperature interval over which hydrous melting takes places is inordinately large and contrary to expectations, and/or (3) the possibility that the system may be above the second critical end point (SCEP) in this H2O-rich silicate system has been insufficiently discussed. In this reply, we provide clarification on these concerns and argue that with the extent of knowledge available today, the chemical characteristics of our experimental products at 3.2 and 4 GPa evince the presence of a silicate melt at temperatures <1,000 °C and we are below the SCEP in the peridotite–H2O system at the P–T conditions of our experiments. If in fact the quench observed in our experiments does represent that of a supercritical (SC) fluid, then our data suggest Mg and Fe are highly soluble in SC fluids at the P–T conditions of the base of the mantle wedge below arc volcanoes. Therefore, our results would require a significant change in thinking about the chemical compositional characteristics of SC fluids.

Keywords

H2O-saturated Peridotite solidus Hydrous melting Chlorite Second critical end point 

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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Christy B. Till
    • 1
    • 3
  • Timothy L. Grove
    • 1
  • Anthony C. Withers
    • 2
  1. 1.Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeUSA
  2. 2.Department of Geology and GeophysicsUniversity of MinnesotaMinneapolisUSA
  3. 3.United States Geological SurveyMenlo ParkUSA

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