Quantitative evaluation of crystal growth and nucleation rates is important for understanding magmatic processes. Crystal Size Distribution Theory suggests that in a plot of the ln(n) vs. L, slope of the line is equal to -1/Gt where G is the crystal growth rate and t is the magma residence time. Therefore, if t is known then G can be calculated. In a basaltic rock from the Kilauea volcano in Hawaii where both plagioclase and olivine are present, we plotted ln(n) vs. L for the plagioclase as well as for the olivine. Using the known growth rate of plagioclase (10-10 cm/sec) we first calculated the magma residence time (t), and assuming that it is the same for the olivine we used the slope of the ln(n) vs. L line and solved for the growth rate (G) for the olivine. We calculated a value of 10-8.5 cm/sec for the olivine growth rate in a basaltic melt, which is comparable to < 10-10 to 10-7 cm/sec given by Donaldson and Jambon et al. ( 1992 ).
Discipline Categories: Volcanology, Petrology, Igneous, Mineralogy/CrystallographyPreferred Presentation Type: Poster