European Geosciences Union General Assembly 2015 - Garnet Classification
Estimates of metasomatic melts composition
EUROPEAN
GEOSCIENCES UN
Gen
General
Assembly
The REE profiles of calculated melts in equilibrium with Group I garnets and clinopyroxenes
are very similar with composition of autoliths from Grib kimberlite and theoretical 1.5%
partial melt carbonated depleted mantle [Grassi, 2010] using partition coefficient for
near-solidus carbonatitic liquid at T = 1265 °C [Dasgupta et al., 2009];
The REE profiles of calculated melts in equilibrium with Group II garnets are similar to Grib
kimberlite using partition coefficient for deep lithospheric mantle situations at T = 1300 °C
[Dasgupta et al., 2009; Johnson et al., 1999];
1000
Sample C1 (Sun & McDonough, 1989)
100
10
10
0.1
equilibrium
with Gar
equilibrium with Cpx
1.5% melt of carb.
peridotite, Grassi, 2010
1000
Sample C1 (Sun & McDonough, 1989)
equilibrium
||
with Gar
100
Griba, autoliths
Griba, kimberlite
10
10
-
Kd 1300 °C, Johnson et al., 1999
0.1
Group I
Griba, autoliths
Kd- Dasgupta et al., 2009
Griba, kimberlite
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
!
...0
Group II
Group II
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
This suggests evolutionary increasing in silicate components for melts in
equilibrium with Group I garnet to Garnet II.
2015
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