R7: Petrology, Mineralogy and Economic geology (Joint Session with Society of Resource Geology)

[R7P-03] Crystal seze distribution analysis of mottled anorthosite in the Bushvelt complex, South Africa

*YOSHIDA SHUHEI¹, ECHIGO TAKUYA¹, WATANABE YASUSHI¹ (1. Akita University. Graduate School of International Resource Sciences)

Keywords:Bushveld complex, Mottled anorthosite, Crystal size distribution

We investigated the crystal growth process of the mottled anorthosite in the eastern limb of the Bushvelt complex by optical microscope, SEM-EDS analysis and crystal size distribution (CSD) analysis. This anorthosite is composed of white matrix of plagioclase and dark brown mottles of pyroxene. The obtained CSD curve show a maximum value and there was no difference in the composition of plagioclase in the white matrix and dark brown mottles. These results suggest that the crystal growth process of the anorthosite involves annealing and/or resorption-recrystallization.