Priv.-Doz. Dr. rer. nat. Armin Freundt

Physical volcanology

Investigation of pyroclastic deposits, also called tephras (both terms mean fragmented material generated by an explosive volcanic eruption), on land and in the sea in order to reconstruct the mechanisms of explosive eruption, transport and emplacement. This also addresses the potential hazards of explosive volcanic activity.

Geochemistry and petrology of igneous rocks

as tools to trace the evolution of magmas from the mantle through the crust to the point of eruption. Particularly important is the evolution of volatile phases (H2O, CO2, S, halogens, etc., i.e., matter released as gas during eruption) because of their role in the eruption process relative to the influence of external factors such as magma contact with seawater, and because of their potential as climate-forcing agents.

Tephrostratigraphy

Deciphering the temporal sucession of volcanic, and particularly explosive events is essential to understand how single volcanoes, volcanic complexes, and entire geotectonic volcanic settings evolve in terms of magma compositions and eruptive behavior, and their controlling parameters. Such evolutionary trends can be extrapolated to estimate future developments and risks. Time series of volcanic activity can then also be compared with time series of environmental and paleo-climate proxies in order to constrain the mutual interactions. When erupted magma masses can be constrained together with geochemical compositions, tephrostratigraphy facilitates the determination of elemental budgets and fluxes through geotectonic systems such as subduction zones.

Volcanic ocean islands and subduction zone volcanism are the favored settings for my work, and both require to combine field work and sampling on land with marine expeditions designed to sample distal tephras from eruptions on land as well as tephras from submarine eruptions.