Investigations on the Experimentally Produced Chondrules: Chemical Compositions of Olivine and Glass and Formation of Radial Pyroxene Chondrules

Recently, textures of chondrules have been reproduced experimentally by cooling liquids of chondrule compositions, and thereby the cooling rate of chondrules during their crystallization has been estimated (TSUCHIYAMA et al. : Earth Planet. Sci. Lett., 48,155,1980). In the present study, the chemical compositions of olivine and glass of run products in the previous experiments were determined. Olivine crystals are normally zoned. The chemical compositions of glasses are extremely enriched in SiO_2 due presumably to disequilibrium crystallization of olivine by rapid cooling. Similar glasses have been observed in unequilibrated chondrites. Additional experiments were also performed to produce radial pyroxene texture which could not be produced in the previous experiments. The radial pyroxene was formed by reaction between radial olivine and residual SiO_2-rich liquid without changing its texture. This process might be a possible mechanism of formation of radial pyroxene texture of chondrules