Nicolas Riel's seminar, Institute of Geosciences, Johannes Gutenberg Univesity Mainz, Germany

Toward a chemical, thermal and mechanical model of partially molten systems

Nicolas Riel's seminar, 2019

Abstract

The deep hot crust is known to play a major role in the Earth's chemical exchanges via extensive partial melting and melt segregation leading to plutonism and volcanism. Partial melting in the lower crust not only participates to the chemical dierentiation of the Earth’s crust but also creates a two-phase medium (solid and liquid parts) which strongly controls rock rheology and is thought to have a primary role on the formation of large orogenic systems such as the Himalayan-Tibet and the Altiplano-Puna. The genesis, dynamics and stability of these high-temperature sequences are dicult to assess as deep sections of the crust are rarely exposed and commonly are the products of complex and repeated tectono-meta/magmatic events.
In this presentation two case-study of deep hot crustal zone will be discussed. The rst one focuses on the chemical and physical mechanisms of reactive magma transfer at the root of volcanic arc systems using coupled petrological and two-phase ow numerical modelling. The second one investigates the tectono-magmatic evolution of a partial-molten lower crust from a petrological, metamorphic and thermal modelling point of view. In the light of these two examples, a combination of petrological and numerical strategies will be discussed in order to develop a new and comprehensive coupled chemical, thermal and mechanical numerical model.