Phase partitioning during fragmentation revealed by QEMSCAN Particle Mineralogical Analysis of volcanic ash.

ABSTRACT: Volcanic ash particle properties depend upon their genetic fragmentation processes. Here, we introduce QEMSCAN Particle Mineralogical Analysis (PMA) to quantify the phase distribution in ash samples collected during activity at Santiaguito, Guatemala and assess the fragmentation mechanisms. Volcanic ash from a vulcanian explosion and from a pyroclastic density current resulting from a dome collapse were selected. The ash particles resulting from both fragmentation modes are dense and blocky, typical of open-vent dome volcanoes and have a componentry consistent with their andesitic composition. We use image analysis to compare the fraction of each phase at particle boundaries compared to the total particle fraction. Our results show that the explosion-derived ash has an even distribution of

SUBMITTER: Hornby AJ 

PROVIDER: S-EPMC6333781 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature