0.5GPa，800°Cにおけるメノウ中の石英多結晶体の結晶成長実験

抄録

We investigated grain growth process of quartz aggregates in agate. The agate samples were annealed in a piston-cylinder solid medium apparatus (MK65S) of Shizuoka University. The experiments were performed at temperature of 800°C, confining pressure of 0.5 GPa for 0.5 hr, 24 hr and 66 hr, respectively. The agates were well crystallized during experiments. Mean grain sizes increased from a few to ten microns with increasing time. Aspect ratios were nearly constant at around 0.7 (b/a; b < a). Shape preferred orientation (SPO) of quartz grains were developed with increasing time. Crystal-preferred orientation of c-axes, which were primarily girdled, appears to control the development of SPO with time.