Analysis of experimental data on the diffusion coefficients of Fe, Mn, Mg, and Ca in garnets
V.N. Korolyuk, G.G. Lepezin*
Institute of Geology and Mineralogy, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Diffusion coefficients; compensation law; garnets; metamorphism; duration
Pages: 557-569
Subsection: PETROLOGY, GEOCHEMISTRY AND MINERALOGY
Abstract
Experimental data on the diffusion coefficients of Fe, Mn, Mg, and Ca in garnets are generalized. Frequency factors (cm2/s), activation energies (cal/mole), and activation volumes (cm3/mole) are optimized. Based on the compensation law, the dependences of diffusion coefficients on pressure (kbar) and temperature (K) have been derived:
D Fe = 1.0 · 10-3 exp [ - (61450 + 23.9 · 8 · P ) / (RT) ] ,
D Mn = 2.3 · 10-6 exp [ - (44600 + 23.9 · 6 · P) / (RT) ] ,
D Mg = 4.9 · 10-3 exp [ - (65900 + 23.9 · 9.2 · P ) / (RT) ] ,
D Ca = 4.1 · 10-5 exp [ - (62450 + 23.9 · 11.2 · P) / (RT)] .
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