Spatial point pattern analysis applied to bubble nucleation in silicate melts

Abstract

Experimental bubble nucleation studies are used for determining the nucleation mechanism as a function of experimental conditions, the resulting bubble number density, and can also yield estimates of the melt-vapor surface tension. This provides important information on gas exsolution in silicate melts, which can be applied towards understanding magmatic degassing in volcanic conduits. At present, determination of nucleation processes in tiny experimental samples relies upon visual observations. To improve the characterization of the spatial distribution of bubbles, we present a new application of spatial point pattern analysis. This technique allows the quantitative description of the spatial distribution of nucleation sites and has the potential to distinguish between homogeneous, heterogeneous, and multiple nucleation events. Since point pattern analysis highlights clustering or spatial regularity among objects, it may improve our understanding of the melt structure underlying the spatial distribution of nucleation sites, as well as interactions between bubble populations resulting from different nucleation pulses within a single experimental sample.