Kinetics of the melting of albite plus forsterite at high pressures
Experiments involving the melting of albite plus forsterite at 1.85 +/- .03 Gp indicate a significant time dependence for this reaction. A time versus temperature plot produces an exponential curve which becomes time-independent in runs of duration greater than 100 hours. When plotted as log (1/time) vs. 1/temperature, the data can be explained by three linear regions: one with a vertical slope at T = 1170 +/- 5/sup 0/C indicating the equilibrium (i.e., time independent) melting temperature; a region between time = 24 hours and 100 hours and apparent melting temperatures between 1300/sup 0/C and 1170/sup 0/C; and a region for runs shorter than 24 hours and temperatures greater than 1300/sup 0/C. Glass (quenched liquid) is the only reaction product present in runs less than 24 hours in duration whereas glass plus crystals of enstatite are present in longer duration experiments. The authors interpret these results as indicating that enstatite plus liquid are the equilibrium reaction products of the melting of albite plus forsterite at this pressure and that the sluggish nature of the melting process necessitates superheating of the reactants to temperatures in excess of the liquidus before any melting will occur in short run times, whereas longer runs allow melting to occur between the solidus and the liquidus, a region which contains enstatite in equilibrium with liquid. This kinetic effect is similar to observations made by Boettcher et al. (1982) in a study of pure albite at high pressures.
- Research Organization:
- Iowa State Univ., Ames (USA)
- OSTI ID:
- 6069932
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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