A novel apparatus for the simulation of eruptive gas-rock interactions

The chemical interactions between hot volcanic gases and co-erupted magmatic and lithic particles within eruption plumes and pyroclastic flows are increasingly investigated for their relevance to the impacts of ash emission on natural and human environments. Laboratory experiments are critical to our understanding of high-temperature gas-ash interactions, but previous studies are yet to replicate the chemical composition of the high-temperature volcanic gases involved. Here, we present a unique apparatus, the Advanced Gas-Ash Reactor, capable of generating an atmosphere of H₂O, CO₂, SO₂ and HCl at temperatures ranging from 200 to 900 °C, under variable heating and cooling rates. Experiments utilising the reactor can inform investigations of a range of topics, from subsurface gas-rock interaction and in-plume gas adsorption processes, to the effect of ash surface chemistry on marine nutrient loadings and atmospheric chemistry. Our results demonstrate the differences in high-temperature gas uptake by volcanic glass powders under both hydrous and anhydrous atmospheres and, accordingly, demonstrate the utility of the new reactor.