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Viscous and frictional strength of the lithospheric mantle : microstructural characterization of experimentally deformed polycrystalline Olivine Manuel Thieme To cite this version: Manuel Thieme. Viscous and frictional strength of the lithospheric mantle : microstructural char- acterization of experimentally deformed polycrystalline Olivine. Tectonics. Université Montpellier, 2018. English. NNT : 2018MONTG061. tel-01982202v2 HAL Id: tel-01982202 https://tel.archives-ouvertes.fr/tel-01982202v2 Submitted on 22 Feb 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THÈSE POUR OBTENIR LE GRADE DE DOCTEUR DE L’UNIVERSITÉ DE M ONTPELLIER En Géosciences École doctorale GAIA Unité de recherche UMR 5243 Viscous and frictional strength of the lithospheric mantle: Microstructural characterization of experimentally deformed polycrystalline Olivine Présentée par Manuel THIEME Le 08 novembre 2018 Sous la direction de Dr. Sylvie Demouchy et Dr. David Mainprice ! Devant le jury composé de Stéphane MAZZOTTI, Professeur, Géosciences Montpellier, Université de Montpellier Président du jury Whitney BEHR, Professor, Geological Institute, ETH Zürich Rapportrice Anne DAVAILLE, DR CNRS, Laboratoire FAST, Université Paris-Sud Examinatrice Sylvie DEMOUCHY, CR CNRS HDR, Géosciences Montpellier, Université de Montpellier Directrice de thése Alexandre DIMANOV, CR CNRS HDR, Lab. Mécanique des Solides, Mines ParisTech Rapporteur David MAINPRICE, DR CNRS, Géosciences Montpellier, Université de Montpellier Co-directeur de thése Maurine MONTAGNAT-RENTIER, DR CNRS, IGE, Université-Grenoble-Alpes Examinatrice ! ! ! ! ! ! ! ! ! ! ! !"#$%&'()!-!Everything!flows.!!! Heraclitus of Ephesus/Platon/Simplikios ! ! ! ! ! ! Context The results detailed in this thesis were obtained as part of the innovative training network (ITN) complex rheologies in earth dynamics and industrial processes (CREEP, Horizon 2020, Marie Sklodowska-Curie grant agreement No. 642029). The CREEP network is a coherent platform for training and career development in Geodynamics, Mineral Physics, Seismology, Fluid Mechanics and Materials Sciences, bringing together scientists from 10 academic centers and 11 industrial partners in Europe. CREEP aims to advance our understanding of the complex rheology of Earth and industrial materials, including seismicity (induced or natural), production of fossil or renewable energy and rheology of industrial materials like glass. To this end, CREEP uses a fully multidisciplinary approach including mineral physics, petrology, seismology and geodynamics, spanning the large range of scales from the atomistic processes in crystals to global mantle dynamics. The main aim of ITN CREEP is to train 16 early stage researchers in state-of-the-art concepts and research techniques, while providing networking opportunities and courses and workshops on career-management skills. Finally, the impact and international visibility of European research is strengthened by communicating results to the public and facilitating exchange between the involved partners. Deformation experiments for Chapter V (shear deformation of nano- and micro-crystalline olivine at seismic slip rates) were performed as part of my academic secondment with the Rock Mechanics Laboratory, Durham University, UK. I additionally spent a one-month internship at the Montpellier Technology Center (Schlumberger; https://www.slb.com/about/rd/technology/mptc.aspx) in colloboration with Frantz & Laurent Maerten as my industrial secondment. Annex A contains the abstract of Effect of pressure and temperature on viscosity of N-BK7 glass , of which I am co-author. Experiments for this paper were performed in Montpellier in collaboration with the Institute of Geosciences, University of Mainz, as part of the CREEP network. [! I!]! ! ! [! II!]! ! ! Acknowledgements I thank my supervisors Sylvie Demouchy and David Mainprice for their insights, patience, support, and little tips and tricks. I am especially grateful to Sylvie for her determination and Zen-approach during long evenings in the lab. I believe it was the methodological problem solving, the tons of chocolate and the tea and maybe the little golden Ganesha that kept the deformation apparatus in check. Likewise, I want to thank the CREEP network, in particular Andrea Tommasi and Alida Lefter for providing me with countless opportunities to broaden my scientific horizon and develop new skills and methods, building a strong base for my future career. This included incentives and time for scientific outreach, internships, workshops and short courses. I thank the Jury for accepting to review and judge this study. I am grateful to Fabrice Barou, Nicolas Marino, Christophe Nevado and Dorianne Delmas for their help and tips during sample preparation and EBSD analysis. Nicolas, thank you for making me speak french and showing/teaching me some manual skills! Moreover, I thank Nicola DePaola for enabling me to perform my internship at the Rock Mechanics Laboratory, University of Durham and Giacomo Pozzi for his contribution to the experiments there and for being a perfect host. I want to express my gratitute to Frantz and Laurent Maerten for the opportunity of an internship at the Montpellier Technology Center (Schlumberger). I thoroughly enjoyed the contacts and connections I made there, the insights into industry work flows and live and the shared lunches ending in a few surprising opportunities. I am deeply grateful for Alida Lefters support with administration during my first year in France. You made my arrival so much more smooth and effortless and showed me corners of Montpellier I would not have found by myself. In no particular order I would like to thank Jose Alberto Padrón-Navarta, Catherine Thoraval, Anne Delplanque, Hélène Ournat and Marie Deguillon, for fruitful conversations and diverse help. Last but certainly not the least I want to thank my family and friends who tolerated and supported me during this time and occasionally helped me to distract me from the science and bring me back down to earth. It would have been quite something else without you. You know who you are, you are the best! [! III!]! ! ! [! IV!]! ! ! Résumé en français La déformation est un processus fondamental pour la dynamique des planètes tellurique, en particulier la tectonique des plaques sur Terre. Elle façonne la topographie actuelle, elle genère la formation de gisements de ressources ou elle est responsable des séismes superficiels et profonds. La cinématique et la géométrie de la tectonique des plaques sont directement liées à des forces motrices profondes contrôlées par le refroidissement de la Terre et par à la convection du manteau, avec en surface la formation de dorsales océaniques, de z ones de subduction et de déformations localisées à l’interface entre la croûte et le manteau supérieur. Le manteau supérieur est divisé en manteau lithosphérique solide et sous celui-ci le manteau asthénosphérique, plus chaud et donc moins visqueux. Le manteau lithosphérique est une couche de couplage partiel entre la base des plaques tectoniques rigides et l'asthénosphère convective sous-jacente. Les propriétés physiques de cette couche et l’amplitude du contraste de viscosité entres la lithosphère et l’ asthénosphère, sont encore un sujet discussion en géodynamique. Entre 300 et 500 °C, les mécanismes de déformation dominants passent progressivement du glissement cassant dans les failles à du frottement, puis à des mécanismes ductiles (par exemple glissement de dislocation, processus aux joints de grains ou encore maclage). C’est la transition dit e fragile-ductile. La composition chimique et minéralogique des roches va aussi concourir à la résistance aux déformations cisaillantes. Nous avons choisi d’ét udier la transition fragile-ductile par une approche expérimentale. Puisque les expériences de déformation en laboratoire sont de durée limitée, nous avons besoin d’une compréhension physique précise des mécanismes impliqués lors de la déformation permanente, cassante et ductile pour pouvoir extrapoler les résultats aux échelles de temps et d’espac e caractéristiques de la Terre. La modélisation atomistique reste encore trop coûteuse en calcul pour modéliser une roche polycristalline et polyminérale dans tou te sa complexité. À l’heure actuelle, l'approche la plus directe pour comprendre les mécanismes de déformation consiste à examiner les textures des roches et les niveaux de contraintes et leurs corrélations avec les données mécaniques enregistrées en laboratoire lors [! V!]! ! ! d’essais mécaniques (contraintes, déformations finies, vitesses de déformation à u ne température et une pression données). Une fois les processus de déformation identifiés, ils peuvent ensuite être implémentés via des règles de comportement dans des modèles numériques d’interactions de dislocations et autres défauts cristallins pour pou voir changer d’échelle de vitesse de déformation (10 -5 s-1 au laboratoire, 10 -14 s-1 dans la manteau). Cette thèse a été réalisée dans le cadre d’un projet européen ‘CREEP’ (Marie Sklodowska-Curie
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