Plucked Apart: Grain-Scale Mechanics of Mafic Enclave Disintegration

Mafic magmatic enclaves are common in silicic magmatic systems and often signal recharge of shallowly stored magma with basaltic magma from depth. They are associated with volcanic eruption triggers and help sustain shallow magma systems. After formation, enclaves may settle, erupt, or remain mobile, but their fate is mostly unknown. Textures like glassy rims and high crystallinity reflect their response to mixing and flow. Convective motion can disrupt boundaries between magmas, and over time, the magma body can hybridize through diffusion and mechanical breakdown.
This study investigates how mechanical disintegration affects the survival of mafic enclaves during mixing. The enclave interface can erode as crystals are plucked away by fluid-solid interactions, gradually shrinking the enclave. We use a new numerical model (LBM-DEM) to simulate the mechanical response of crystals at the enclave boundary and explore how these interactions influence the rate of enclave breakup.
Our simulations show that at high viscosities, the breakup process becomes independent of viscosity. Instead, fluid influx and the initial position of crystals mainly control the rate of enclave disintegration.