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


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.


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


  1. Ayers J, Dittmer S (1997) Partitioning of elements between peridotite and H2O at 2.0–3.0 GPa and 900–1100 C, and application to models of subduction zone processes. Earth Planet Sci Lett 150:381–398CrossRefGoogle Scholar
  2. Bureau H, Keppler H (1999) Complete miscibility between silicate melts and hydrous fluids in the upper mantle: experimental evidence and geochemical implications. Earth Planet Sci Lett 165(2):187–196CrossRefGoogle Scholar
  3. Gaetani GA, Grove TL (1998) The influence of water on melting of mantle peridotite. Contrib Mineral Petrol 131(4):323–346CrossRefGoogle Scholar
  4. Hayden LA, Manning CD (2011) Rutile solubility in supercritical NaAlSi3O8–H2O fluids. Chem Geol 284:74–81CrossRefGoogle Scholar
  5. Hill RET, Boettcher AL (1970) Water in the Earth’s Mantle: melting curves of basalt-water and basalt-water-carbon dioxide. Science 167(3920):980–982CrossRefGoogle Scholar
  6. Hodges FN (1973) Solubility of H2O in Forsterite Melt at 20 Kbar. Carnegie Institute of Washington Yearbook 72:495–497Google Scholar
  7. Hodges FN (1974) The solubility of H2O in silicate melts. Carnegie Institution of Washington Year Book 73:251–255Google Scholar
  8. Kessel R, Ulmer P, Pettke T, Schmidt MW, Thompson AB (2004) A novel approach to determine high-pressure high-temperature fluid and melt compositions using diamond-trap experiments. Am Mineral 89(7):1078–1086Google Scholar
  9. Kessel R, Ulmer P, Pettke T, Schmidt MW, Thompson AB (2005) The water-basalt system at 4 to 6 GPa: phase relations and second critical endpoint in a K-free eclogite at 700 to 1400 degrees C. Earth Planet Sci Lett 237(3–4):873–892CrossRefGoogle Scholar
  10. Kinzler RJ (1997) Melting of mantle peridotite at pressures approaching the spinel to garnet transition: application to mid-ocean ridge basalt petrogenesis. J Geophys Res 102(B1):853–874CrossRefGoogle Scholar
  11. Kinzler RJ, Grove TL (1992) Primary Magmas of Midocean Ridge Basalts 1. Experiments and Methods. J Geophys Res 97(5):6885–6906CrossRefGoogle Scholar
  12. Kogiso T, Hirschmann MM, Frost DJ (2003) High-pressure partial melting of garnet pyroxenite: possible mafic lithologies in the source of ocean island basalts. Earth Planet Sci Lett 216:603–617CrossRefGoogle Scholar
  13. Lambert IB, Wyllie PJ (1970) Melting in the deep crust and upper mantle and the nature of the low velocity layer. Phys Earth Planet Int 3:316–322CrossRefGoogle Scholar
  14. Liu J, Bohlen S, Ernst W (1996) Stability of hydrous phases in subducting oceanic crust. Earth Planet Sci Lett 143:161–171CrossRefGoogle Scholar
  15. Mibe K, Kanzaki M, Kawamoto T, Matsukage KN, Fei Y, Ono S (2007) Second critical endpoint in the peridotite-H2O system. J Geophys Res 112. doi: 10.1029/2005JB004125
  16. Schneider M, Eggler D (1986) Fluids in equilibrium with peridotite minerals—implications for mantle metasomatism. Geochim Cosmochim Acta 50(5):711–724CrossRefGoogle Scholar
  17. Stalder P, Ulmer P, Thompson A, Günther D (2000) Experimental approach to constrain second critical end points in fluid/silicate systems: near-solidus fluids and melts in the system albite-H2O. Am Mineral 85(1):68–77Google Scholar
  18. Stalder R, Ulmer P, Thompson A, Günther D (2001) High pressure fluids in the system MgO–SiO2–H2O under upper mantle conditions. Contrib Mineral Petrol 140(5):607–618. doi: 10.1007/s004100000212 CrossRefGoogle Scholar
  19. Till C, Grove T, Withers AC (2012) The beginnings of hydrous mantle wedge melting. Contrib Mineral Petrol 163:669–688. doi: 10.1007/s00410-011-0692-6 CrossRefGoogle Scholar
  20. Vielzeuf D, Schmidt M (2001) Melting relations in hydrous systems revisited: application to metapelites, metagreywackes and metabasalts. Contrib Mineral Petrol 141(3):251–267CrossRefGoogle Scholar

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

Personalised recommendations