Cooling rate estimations based on kinetic modelling of Fe-Mg diffusion in olivineA finite one-dimensional kinetic model was developed to estimate the cooling rates of lunar rocks. The model takes into consideration the compositional zonation of olivine and applies Buening and Buseck (1973) data on ion diffusion in olivine. Since the 'as-solidified' profile of a given olivine is not known, a step-function, with infinite gradient, is assumed; the position of this step is based on mass balance considerations of the measured compositional profile. A minimum cooling rate would be associated with the preservation of a given gradient. The linear cooling rates of lunar rocks 12002 and 15555 were estimated by use of the olivine cooling-rate indicator to be 10 C/day and 5 C/day, respectively. These values are lower than those obtained by dynamic crystallization studies (10-20 C/day).
Document ID
19780057742
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Taylor, L. A. (Tennessee, University Knoxville, Tenn., United States)
Onorato, P. I. K. (Tennessee Univ. Knoxville, TN, United States)
Uhlmann, D. R. (MIT Cambridge, Mass., United States)