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High strain zone: From the effect of mineral plasticity to plate tectonic

Applicant Kaczmarek Mary-Alix
Number 166933
Funding scheme Ambizione
Research institution Institut des sciences de la Terre Université de Lausanne
Institution of higher education University of Lausanne - LA
Main discipline Geology
Start/End 01.04.2016 - 30.06.2017
Approved amount 150'948.00
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All Disciplines (4)

Discipline
Geology
Other disciplines of Earth Sciences
Geochemistry
Mineralogy

Keywords (6)

Melt-fluid interaction; Geochemistry; microtexture; In-situ; Deformation; EBSD

Lay Summary (French)

Lead
Plate tectonic processes shape the Earth’s surface, and is a fundamental control on the movement of tectonic plates is the way in which the Earth’s mantle deforms and accommodates mantle convection. Tectonically driven deformation of the lithosphere my lead to strain localization through the formation of ductile shear zones, and their development is responsible for lithospheric scale deformation processes that control the nature and distribution of Earth’s tectonic plates.
Lay summary

Durant les deux dernières décennies, la déformation des minéraux et des roches a été largement documentée et est maintenant reconnue comme ayant une influence fondamentale sur les processus géodynamique à large échelle. En dépit de ces efforts, l’influence de paramètres critiques sur la localisation de la déformation comme les conditions de pression et température, la minéralogie ou la présence de liquide/fluide ne sont toujours pas bien compris. Ce projet a pour but de déterminer si ces paramètres sont critiques et peuvent contrôler la localisation de la déformation dans les matériaux terrestres et des autres planètes. Ce projet a 2 axes : (1) une étude microstructurale et géochimique de météorites et d’échantillons de roche mantellique qui proviennent de contextes en extension pour obtenir des donnes comparatives sur les mécanismes de déformation dans les matériaux terrestres et extraterrestres. (2) Une étude structurale, microstructurale et géochimique d’une zone de cisaillement kilométrique en Oman pour contraindre les interactions fluide/liquide roche pendant la déformation a large échelle dans le manteau supérieur. Ce projet va apporter de nouveaux éléments pour contraindre la variation de la déformation à travers la lithosphère, et une nouvelle base de données pour les scientifiques intéressés dans le comportement de la lithosphère mantellique sur la Terre et les autres planètes. 
C’est une étude pluridisciplinaire combine un analyse structurale, pétrologique, microstructurale et géochimique, utilisant des méthodes avancées comme l’EBSD, un ICP-MS couple a une ablation laser et une sonde ionique. L’EBSD combiné avec une sonde électronique et ionique est un moyen rapide et efficace d’obtenir des données sur la structure cristalline, la chimie et l’orientation des minéraux dans les roches de la Terre et d’autres planètes, qui donnera des nouvelles réponses pour comprendre la dynamique des planètes.

Direct link to Lay Summary Last update: 22.03.2016

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
Macquarie University Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
EOST-ULP, Strasbourg France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Geoscience Environnement Toulouse - CNRS France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
University of Western Ontario Canada (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Curtin University- Perth Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
International Geological Conference Talk given at a conference Interaction of melt and deformation at the lithosphere-asthenosphere boundary 21.08.2016 Le cap, South Africa Kaczmarek Mary-Alix;
Goldschmidt Talk given at a conference Chemical variation and deformation of the upper mantle across an OCT 26.06.2016 Yokohama, Japan Kaczmarek Mary-Alix;


Associated projects

Number Title Start Funding scheme
142454 High strain zone: From the effect of mineral plasticity to plate tectonic 01.04.2013 Ambizione

Abstract

Over the last two decades, the deformation of minerals and rocks in response to stress has been widely documented, and is now recognised as a fundamental influence on large-scale geodynamic processes. Numerous mechanisms, such as temperature, grain size reduction, mineral reaction, and small amounts of fluid/liquid, have been proposed to explain the localisation of shear in deformed materials. In spite of these recent efforts, critical parameters such as deformation mechanisms, the pressure and temperature of deformation, the presence of a particular mineral and on fluid/melt in shear localisation are still not well understood. This project aims to better define these critical parameters as a function of mineralogy, strain and thermal conditions in order to better understand the localisation of shear and distribution of deformation in terrestrial and planetary materials.In this project, I propose to identify the critical mineral reactions, the deformation mechanisms, the thermobarometric conditions and the geochemical variations of the rock that possibly control shear localisation, in several geological contexts. I use a combination of textural analysis including Electron Backscatter Diffraction (EBSD), quantitative mineral analysis and rock mechanics to study mineralogical reactions, mechanisms of deformation and mineral geochemistry, in order to characterise the deformation mechanisms in the mineral and the relationships between deformation and fluid/melt percolation. It is recognised that the presence of fluid and melt has important implications on strain localisation although the mechanisms by which this occurs are still not well constrained. The understanding of the interactions between physical and chemical processes at various scales is fundamental to understand the dynamics of shear zones, orogens and ultimately plate tectonic processes.This project provide a detailed microstructural and geochemical study of samples from various settings (mid-ocean ridge spreading centre, ocean-continent transition, craton) and meteorites to obtain comparative data on shear mechanisms and localisation in ultramafic rocks.I propose a multidisciplinary project combining structural analyses, petrology, microstructures, and geochemistry, using in-situ microbeam techniques such as EBSD, electron microprobe, Laser Ablation ICPMS and Ion probe techniques. EBSD combined with electron and ion probe analysis is a fast and reliable way to acquire data for crystalline structure, chemistry and orientation in solid Earth materials.This study will provide new information inputs to unravel the history and dynamics of tectonic processes recorded in the Earth and other planets. The results will offer new elements to constrain deformation variation across the lithosphere, localisation of deformation and the parameters influencing deformation. I can expect to provide a new dataset to forward modelling of the rheology of the mantle, which is needed to understand mantle deformation on a global scale. The results obtained within the framework of this FNS Ambizione project will give a new dataset for scientists interested in the deformation behaviour of the lithospheric mantle on Earth and in meteorites.
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