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FRINATEK-Fri prosj.st. mat.,naturv.,tek

BEYOND ELASTICITY - How inelastic properties of crustal rocks control the propagation of dykes and sills in volcanic plumbing systems

Alternative title: BORTENFOR ELASTISITET - Hvordan uelastiske egenskaper til jordskorpen kontrollerer forplantningen av diker og sills i vulkanske røtter

Awarded: NOK 12.0 mill.

Understanding the dynamics of volcanoes’ roots is of paramount important to predict volcanic eruptions, assess volcanic hazards, and explore for natural resources (geothermal, ore deposits, hydrocarbons) associated with active and ancient volcanoes. The main conduits transporting magmas in volcanic plumbing systems exhibit planar, sheet shapes, such as vertical dykes and horizontal sills. The aim of the Beyond Elasticity project is to deeply revisiting our understanding of the propagation mechanisms of these fundamental magmatic conduits. The current paradigm of sheet intrusion emplacement in based on the Linear Elastic Fracture Mechanics (LEFM) theory, which states that they propagate by tensile opening and elastic bending of the host rock, like a crack. However, geological observations show that a fundamentally distinct mechanism, so-called viscous indenter, can control the propagation of igneous sheet intrusions, where the intrusion tip indents the host rock that fails by compressional inelastic deformation. Even if both mechanisms have been documented, first-order questions remain unsolved. Are they two end-member propagation mechanisms or are there intermediate regimes combining them? In which geological environments the LEFM and viscous indenter propagation mechanisms occur? To address these questions, the aim of “Beyond Elasticity” is to build novel mechanical understanding that reconciles these two propagation mechanisms, by designing novel elasto-plastic models of sheet intrusion propagation. “Beyond Elasticity” will implement multidisciplinary research that integrates fieldwork in a world-class field case study (Sarek National Park, Sweden), state-of-the-art laboratory and numerical models, and applied mathematics. Such a unique combination of research fields and methods, carried by a team of top-scientists, will ensure beyond state-of-the-art impact of the project results.

The Beyond Elasticity project aims at deeply revisiting our understanding of the propagation mechanisms of magmatic sheet intrusions (dykes, sills and cone sheets), which are the most fundamental magma pathways through the Earth’s crust. Revealing their propagation dynamics is of paramount relevance for (1) understanding the dynamics of volcanic plumbing systems, (2) volcanic hazard assessment through physically relevant interpretation of geophysical and geodetic data monitored at active volcanoes, and (3) exploration for natural resources (geothermal, ore deposits, hydrocarbons) associated with igneous intrusions. The current paradigm of sheet intrusion emplacement in based on Linear Elastic Fracture Mechanics (LEFM), which states that they propagate by tensile opening and elastic bending of the host rock. However, geological observations show that a fundamentally distinct mechanism, so-called viscous indenter, can control the propagation of igneous sheet intrusions, where the intrusion tip indents the host rock that fails by compressional inelastic deformation. Even if both mechanisms have been documented, first-order questions remain unsolved. Are they two end-member propagation mechanisms or are there intermediate regimes combining them? In which geological environments the LEFM and viscous indenter propagation mechanisms occur? To address these questions, the aim of “Beyond Elasticity” is to build novel mechanical understanding that reconciles these two propagation mechanisms, by designing novel elasto-plastic models of sheet intrusion propagation. “Beyond Elasticity” will implement multidisciplinary research that integrates fieldwork in a world-class field case study (Sarek National Park, Sweden), state-of-the-art laboratory and numerical models, and applied mathematics. Such a unique combination of research fields and methods, carried by a team of top-scientists, will ensure beyond state-of-the-art impact of the project results.

Funding scheme:

FRINATEK-Fri prosj.st. mat.,naturv.,tek