Mathieu CHASSÉ

Assistant Professor

 

Ph. D. in Geosciences
Institut de minéralogie, de physique des matériaux et de cosmochimie, Sorbonne University (Paris)


Research speciality: Mineralogy and speciation of chemical elements in the environment
Curriculum Vitae

Research interests:

  • Crystal chemistry of amorphous and cristalline phases.
  • Chemical elements dynamics and implications for critical mineral resources.
  • Mineral-organic associations and soil organic carbon dynamics.

About me

    My current research focuses on the speciation of chemical elements in the environment. My career path provides me with a strong expertise in mineralogy and (bio)geochemistry, in particular in the synthesis and identification of mineral phases as well as in the techniques of characterisation at micro- and nano-scales to study the associated chemical species. I wish to work on projects on chemical elements mobility in supergene conditions, focusing on critical metals, in order to foster the diversification of these resources. Fundamentally, I aim at improving our understanding of the alteration processes at stake in the formation and evolution of Earth's critical zone.

Work

  • Thesis
  • Thesis
  • Thesis

Element Speciation in Natural Glasses

Transition element speciation plays a key role in the physical and chemical properties of glasses. I use spectrophotometry to study iron speciation in natural glasses (obsidians, tectite, glass inclusions). These results are interpreted in terms of conditions of formation of the glasses such as thermal history or redox.
I also used this technique to study the influence of chromium in the colour of pigments from the Manufacture de Sèvres.
Location: Institut de minéralogie, de physique des matériaux et de cosmochimie, Sorbonne Université, Paris
Collaborations: O. Alard, G. Calas, L. Galoisy, G. Lelong, N. Métrich, L. Verger, OMT Solutions
Articles:
Chassé et al. (2015) Appl. Spectrosc. 69:4, 457-463.
Verger et al. (2017) J. Cult. Herit., 30, 26-33.

 
  • Thesis
  • Thesis
  • Thesis

Processes Concentrating Critical Metals

The supply of rare metals has become a topic of great concern. Among others, scandium is required due to its technological interest. Lateritic deposits are promising targets. To understand their origin, I combine geochemical and mineralogical approaches at experimental and theoretical levels, from deposit- to molecular scale.
Location: Institut de minéralogie, de physique des matériaux et de cosmochimie, Sorbonne Université, Paris / ARC Centre for Core to Crust Fluid Systems, Macquarie University, Sydney
Collaborations: O. Alard, M. Blanchard, D. Cabaret, G. Calas, W. L. Griffin, A. Juhin, S. Y. O'Reilly, D. Vantelon, Jervois Mining Limited
Articles:
Chassé et al. (2017) Geoch. Persp. Lett. 3, 105-114.
Chassé et al. (2018) Lithos 310-311, 409-421.
Chassé et al. (2018) PCCP 20, 23903.

 
  • Thesis
  • Thesis
  • Thesis

Stabilisation of Soil Organic Carbon

I aim at improving the understanding of soil organic carbon dynamic, a crucial challenge to mitigate climate change. In this view, I study long-term bare fallow soil samples. These soils are kept free from vegetation during several decades and regularly sampled. Carbon inputs being stopped, the decomposition of the most labile compounds progressively leads to the isolation of the most stable fraction of soil organic carbon. I combine geochemical and mineralogical approaches in order to determine the speciation of stable carbon as well as the nature of mineral-organic associations favouring this stability.
Location: Laboratoire de géologie de l'École normale supérieure (Paris) / Institut des sciences de la Terre de Paris, Sorbonne Université
Collaborations: P. Barré, F. Baudin, S. Bernard, C. Chenu, C. Le Guillou.

 
M. Sc. Project Element Speciation in Glasses
Ph. D. Project Critical Metal Enrichments
Post-doc Project Soil Organic Carbon Stabilisation

Enseignements

From General Geosciences Knowledge to Fundamental (Bio)geochemical and Mineralogical Processes

    Teaching in the UFR Terre, environnement, biodiversité (Sorbonne Université, Paris)
  • Licence 1, Biology, Geosciences, Chemistry (BGC): Academic advisor; Geosciences 1 and 2.
  • Licence 2, Art History and Archaeology: Environment and Heritage.
  • Licence 3, Earth Sciences: Environment and Heritage; Resources; Geochemistry.
  • Master 1, Earth and Planetary Sciences, Environment: Geochemistry; Experimental Project; Energy and Mineral Resources from Subsurface.
  • Supervision: two months research internship (master 1 Earth and Planetary Sciences, Environment); intern: Qi Qi.
  • Detailed list of teaching units, hourly volume and contents (in French)

Skills

From Outcrop Analyses to Molecular-Scale Studies

  • Geochemistry: (laser-ablation)-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectrometry (XRF).
  • Chemistry: wet chemistry for ICP-MS analyses, selective leaching, hydrothermal synthesis.
  • Mineralogy: electron microprobe (EMP), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD).
  • Spectroscopy: optical absorption spectroscopy on solid phases (transmission and diffuse reflectance), implementation of a microspectrophotometer, X-ray absorption spectroscopy (XANES, XMCD).
  • Synchrotron radiation based techniques;
    measurements made at ESRF (Grenoble, France), SOLEIL (Paris, France), CLS (Saskatoon, Canada) and APS (Chicago, United States):
    XANES, EXAFS, XMCD, XRF mapping (trace elements analysis), STXM (nano-scale mapping and chemical analysis).
  • Calculations: ab-initio calculations based on density functional theory (Quantum Espresso suite of codes),
    ligand-field multiplet calculations (Quanty suite of codes).
  • Programming, softwares: Unix/Shell scripting, Python, R, HTML, LateX, Zotero.

Contact

 4 place Jussieu, tour 12-23 -
4e étage - bureau 410, F-75005 Paris
 +33 6 95 14 55 95
Published works are available online on ResearchGate.

2019 | Mathieu CHASSÉ