Mathematics – Logic
Scientific paper
Jul 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005gecoa..69.3683c&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 69, Issue 14, p. 3683-3694.
Mathematics
Logic
17
Scientific paper
Experiments have been carried out to determine the temperature, oxygen fugacity (fO2) and compositional dependence of the tracer diffusion coefficient (D) of calcium in olivine. These data constrain the diffusion coefficient over the temperature range 900 to 1500°C for the three principal crystallographic axes. Well constrained linear relationships between the reciprocal of the absolute temperature and log(D) exist at any given oxygen fugacity. There is a strong dependence of the diffusion coefficient on oxygen fugacity with D ∝ fO2(1/3). This makes a knowledge of the T-fO2 path followed by geological samples a prerequisite for modelling Ca diffusion in olivine. The best fitting preexponential factor (Do) and activation energy (E) to the Arrhenius equation log (D) = log [Do exp(-E/RT)] + 0.31Δ log fO2 for Ca diffusion in olivine at a given oxygen fugacity (fO2*) are given by: diffusion along [100]: log [Do (m2/s)] = -10.78 ± 0.43; E = 193 ± 11 kJ/mol diffusion along [010]: log [Do (m2/s)] = -10.46 ± 0.37; E = 201 ± 10 kJ/mol diffusion along [001]: log [Do (m2/s)] = -10.02 ± 0.29; E = 207 ± 8 kJ/mol where Δ log fO2 = log[fO2*] - log[10-12] with fO2* in units of bars. There is no measurable compositional dependence of the diffusion coefficient between Fo83 and Fo92. Diffusion in Fo100 has a much higher activation energy than in Fe-bearing olivine and has a weaker fO2 dependence.
Chakraborty Subhasish
Coogan Laurence A.
Hain A.
Stahl Sarah
No associations
LandOfFree
Experimental determination of the diffusion coefficient for calcium in olivine between 900°C and 1500°C does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Experimental determination of the diffusion coefficient for calcium in olivine between 900°C and 1500°C, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Experimental determination of the diffusion coefficient for calcium in olivine between 900°C and 1500°C will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1248742