UphillDiffusion and ZFP in Garnets: an Experimental and ATEM Study D. Vielzeuf – CRMCN, Marseilles, France A. Lupulescu – RPI, Troy, USA A. Perchuk – IGEM – Moscow, Russia D. Laporte – LMV, Clermont, France A. Baronnet – CRMCN, Marseilles, France A. Addad – LSPES, Lille, France
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Uphill Diffusion and ZFP in Garnets: an Experimental
and ATEM Study
D. Vielzeuf – CRMCN, Marseilles, France
A. Lupulescu – RPI, Troy, USA
A. Perchuk – IGEM – Moscow, Russia
D. Laporte – LMV, Clermont, France
A. Baronnet – CRMCN, Marseilles, France
A. Addad – LSPES, Lille, France
A garnet grown in a magma chamber
Calcium Phosphorus
A garnet from a magma chamberin the Pyrénées (France)
Cameca SX100, Clermont
Phosphorus
Calcium
1250°C, 13 kbar, 5 days
French TEM national facility
CRMCN – Univ. Marseilles and CNRS :
JEOL 2000FX, with EDS TRACOR 2(spot size 50 nm)
LSPES - Univ. Lille and CNRS :
Philips CM30 with NORAN EDS, STEM mode(spot size, 5.6 nm)
Focused Ion Beam technique
Dif4b - 1200°C - 36 days
Dif4b - 1200°C - 36 days
1 µm
Some preliminary results
Mg
Fe
Darken, 1949
D matrix calculated with MultiDiFlux*
- Mn : ignored- Ca : dependent component
Fe
Fe Mg
Mg
5.91e-19 -2.15e-19
-5.34e-19 2.02e-19
m2s-1
* Dayananda and coworkers
At 1200°C – 1.3 GPa
Curves calculated with Profiler*
*Morral and coworkers
Fe
Fe Mg
Mg
5.91e-19 -2.15e-19
-5.34e-19 2.02e-19
m2s-1
Zero Flux Planes in Garnet
Moving ZFPs for Caψ = 75
-6 -4 -2 0 2 4 6-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
1.5
Flux
, [at
%-c
m/s
] x 1
0-12
Similarity Variable, ζ= x/(4e1e2t)1/2
Fe
Mg
Ca
o
Matano interface
A pair of moving ZFP for Ca
Component Fluxes versus Euler Angleζ= 0
0 50 100 150 200 250 300 350-1.5
-1.0
-0.5
0
0.5
1.0
1.5
Flux
, [at
%-c
m/s
] x 1
0-11
Euler Angle, ψ
Fe
Mg
Ca
113.983 113.983+180=293.983
Conclusion
- Garnets are excellent materials to explore multicomponentdiffusion in minerals.
- Our experimental technique coupled with ATEM analyses allows the determination of extremely small diffusion coefficients.
- Concepts developed in Material Sciences can be applied in Earth Sciences. Conversely, minerals might prove useful for a better understanding of diffusion in multicomponentsystems.