ERC Advanced Grant 'Disequilibirum metamorphism of stressed lithosphere (DIME)'

This project will investigate how mechanical stress affects fluid migration and transformation processes in the various rock units comprising the Earth’s crust and upper mantle (the lithosphere) in situations far from thermodynamic equilibrium.

Major parts of the lithosphere do not contain liquids or gases (fluid phases) and will react too slowly to reach a state of equilibrium when subject to temperature and pressure changes imposed by plate tectonics. Addition of fluids  to such volumes will cause dissipation of energy in the form of heat and irreversible deformation. These processes may in turn affect plate tectonics. Fluid-driven transformation processes may in addition, change the physical and chemical properties of the lithosphere. The consequence of this will be a dynamic coupling between large-scale plate tectonic processes, and small-scale chemical processes in the various rocks comprising the lithosphere.

European Research Council

About the Project

Most changes in mineralogy, density, and rheology of the Earth’s lithosphere take place by metamorphism, whereby rocks evolve through interactions between minerals and fluids. These changes are coupled with a large range of geodynamic processes and they have first order effects on the global geochemical cycles of a large number of elements.

In the presence of fluids, metamorphic reactions are fast compared to tectonically induced changes in pressure and temperature. Hence, during fluid-producing metamorphism, rocks evolve through near-equilibrium states. However, much of the Earth’s lower and middle crust, and a significant fraction of the upper mantle do not contain free fluids. These parts of the lithosphere exist in a metastable state and are mechanically strong. When subject to changing temperature and pressure conditions at plate boundaries or elsewhere, these rocks do not react until exposed to externally derived fluids. Metamorphism of such rocks consumes fluids, and takes place far from equilibrium through a complex coupling between fluid migration, chemical reactions, and deformation processes.

This disequilibrium metamorphism is characterized by fast reaction rates, release of large amounts of energy in the form of heat and work, and a strong coupling to far-field tectonic stress.

Objectives

The overarching goal in DIME is to provide the first quantitative physics-based model of disequilibrium metamorphism that properly connects fluid-rock interactions at the micro and nano-meter scale to lithosphere scale stresses.

In the course of the project we will realize the following technical and scientific advances:

  • Establish a new laboratory to measure surface forces relevant for fluid mediated phase transformations in confined systems
  • Establish the first ever laboratory to study fluid induced reactions under differential stress by in situ micro X-Ray tomography at submicron resolution
  • Provide the first ever 3D models of reaction driven fracturing, accounting for both external differential stress and fluid pressure gradients
  • Carry out the first ever in situ study of natural serpentinization processes

Background

This project is based on research in the multidisciplinary research group Physics of geological processes - PGP working at the interface between physics and geology.

The DIME project has its foundation in Section for Physics of Geological Processes (GEO-PGP), Department of Geosciences, University of Oslo.

Sub-projects

  • Characterization of the transport properties of confined fluid-consuming systems
  • Quantification of the effects of externally imposed differential stress on the progress of fluid induced reactions
  • Quantification of the rates of disequilibrium metamorphism and its tectonophysical effects by ICDP drilling in Oman

Financing

Advanced Grant (AdG), details: ERC-2015-AdG_669972.

Project period is from 2015 to end of 2020.

Cooperation

Published Nov. 4, 2015 1:24 PM - Last modified Oct. 5, 2016 2:52 PM