Fig. 5. Quartz diffusion chronometry results.

(A) Kernel density plot of modeled diffusion length scales for different regions of quartz from all samples. The CL image of a quartz (A-10_02) on the right shows an example of these regions, where the color of the profile corresponds to the kernel density lines on the left. “Cores” are defined as profiles that are coreward of the first visible zonation truncation [circle in (B)]. “Core-int” profiles cross the first visible zonation truncation and thus represent diffusion time since the first resorption event [triangles in (B)]. Note that the modeled diffusion length scales increase toward the core, consistent with longer diffusion times. (B) Diffusion timescales for the cores (circles) and core-interior boundary (triangles) of quartz crystals using the Ti diffusivity of Cherniak et al. (18) at 750°C. Corresponding diffusion length scales are shown on the axis on the right. Regardless of the diffusion coefficient, there is no consistent increase in diffusion length scale up-section. Note that Fukaminato Pfa (green) and Arasaki Pfl (blue) were co-erupted.