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Petrologic Constraints on Mantle Temperature and
Water ContentMarc Hirschmann
University of Minnesota
Stixrude&Lithgow-Bertelloni, 2005
Stixrude&Lithgow-Bertelloni, 2005
Oceanic Crust Production
Langmuir et al., 1992; Asimow et al., 2001
Trace amounts of H2O enhance melting….
Hirth & Kohlstedt, 1996; Asimow & Langmuir, 2003
Saal et al., 2002
H2O (wt.%)
CO
2 (w
t.%
)
MORB and seamount glassesEaster Microplate
Kingley et al. 2002
H2O Storage Capacity
Hirth & Kohlstedt, 1996
Aubaud et al., GRL, 2004
Hirth & Kohlstedt, 1996 Aubaud et al., GRL, 2004
0
50
100
150
200
250
0 200 400 600 800 1000 1200
H2O (ppm wt.)
Initial depth of melting (km)
1550 °C
1450 °C
1350 °C
RIDGE
PLUME
Tp
MELT Experiment beneath EPR
The MELT Seismic Team (1998)Gu et al. (2005)
Dasgupta & Hirschmann (2006) - Nature
Carbonated Melt Catalyzes Grain Growth
Subsolidus Supersolidus
Dasgupta et al. (2004) - EPSLDasgupta et al., 2004
Dasgupta & Hirschmann (2006) - Nature
Origin of Chemical Lithosphere and Volatile induced Melting of PeridotiteHirth & Kohlstedt (1996)
Aubaud et al., 2004
Peridotite Dehydration is aided by Partial Melting
Dasgupta & Hirschmann (2006) - Nature
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)
Deep Carbonated Silicate Melting & H2O Extraction Beneath Ridges
Schmidt+Poli, 1998
Honshu - Van Keken, 2003
(from Gaetani+Grove, 2003)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Tim Grove - unpublished results(thanks, Tim!)
Elliott, 2003
High Temperature Melt or FluidTransfer from the Slab
Kelemen et al. 2003
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Davies&Stevenson, 1992 Mibe et al., 2001
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Kelemen et al., 2003
Temperatures at the baseof the crust based onmetamorphic thermobarometry
(Elkins Tanton et al., 2001)
Mt. Shasta-Medicine Lake
High Temperatures in Arcs- Petrologic Evidence Location Max T
(°C) P
(GPa) Method So urce
Banda 1320 1.2 Melt Inclus ions
Sisson&Bronto, 1998
Cascades 1450 2.2 Inverse Exper iments
Elkins Tanton e t a l., 2001
Japan 1320 -1360
1.7 -2.3 Inverse Exper iments
Tatsu mi et a l. 1983
Japan 1325 1.2 Inverse Exper iments
Kush iro, 1987
N. Tonga 1480 1.5 Inverse Exper iments
Fa lloon&Danyus hevsky,200 0
Aleut ians 1300 1.2 Inverse Exper iments
Draper & Jo hnston, 1991
Thanks for listening…..
