1. Petrologic Constraints on Mantle Temperature and Water Content
Marc Hirschmann
University of Minnesota

2. Stixrude&Lithgow-Bertelloni, 2005

3. Stixrude&Lithgow-Bertelloni, 2005

4. Oceanic Crust Production Langmuir et al., 1992; Asimow et al., 2001

5. Trace amounts of H2O enhance melting….
Hirth & Kohlstedt, 1996;
Asimow & Langmuir, 2003

6. Saal et al., 2002 MORB and seamount glasses Easter Microplate
CO2 (wt.%)
Kingley et al. 2002
H2O (wt.%)

7. H2O Storage Capacity

13. Hirth & Kohlstedt, 1996

14. Aubaud et al., GRL, 2004

15. Hirth & Kohlstedt, 1996
Aubaud et al., GRL, 2004

18. MELT Experiment beneath EPR
Gu et al. (2005)
The MELT Seismic Team (1998)

19. Dasgupta & Hirschmann (2006) - Nature

20. Carbonated Melt Catalyzes Grain Growth
Subsolidus
Supersolidus
Dasgupta et al., 2004
Dasgupta et al. (2004) - EPSL

21. Dasgupta & Hirschmann (2006) - Nature

22. Origin of Chemical Lithosphere and Volatile induced Melting of Peridotite
Hirth & Kohlstedt (1996)
Aubaud et al., 2004
Peridotite Dehydration is aided by Partial Melting

23. Dasgupta & Hirschmann (2006) - Nature

24. Deep Carbonated Silicate Melting Beneath Ridges
Transition from carbonatite to carbonated silicate melts at 3 GPa
Silicate Melting is enhanced in presence of carbonate
Dasgupta & Hirschmann (submitted)

26. Deep Carbonated Silicate Melting & H2O Extraction Beneath Ridges

27. Schmidt+Poli, 1998

29. Honshu - Van Keken, 2003

30. (from Gaetani+Grove, 2003)

31. Tim Grove - unpublished results
(thanks, Tim!)

33. High Temperature Melt or Fluid
Transfer from the Slab
Elliott, 2003

34. Kelemen et al. 2003

35. Davies&Stevenson, 1992
Mibe et al., 2001

36. Temperatures at the base
of the crust based on
metamorphic thermobarometry
Kelemen et al., 2003

38. Mt. Shasta-Medicine Lake
(Elkins Tanton et al., 2001)

40. Thanks for listening…..