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Reference : UMR7590-DANANT-002
Workplace : PARIS 05
Date of publication : Monday, September 30, 2019
Type of Contract : FTC Scientist
Contract Period : 18 months
Expected date of employment : 4 November 2019
Proportion of work : Full time
Remuneration : Between 2700 and 3100 gross monthly salary depending upon experience
Desired level of education : PhD
Experience required : 1 to 4 years
The InSight NASA discovery program mission successfully landed on Mars on November 26th 2018 and the deployment of the scientific payload was completed over a period of about three months in winter 2019. The surface-installed seismometer together with the possibility to perform high precision tracking of Mars rotation and orientation, is allowing collection of unprecedented information on the interior of the planet. However, the interpretation and full exploitation of geodesy and seismic data to produce accurate models of planetary composition, structure and dynamics critically hinges on the knowledge of key physical properties of pertinent materials at pertinent pressure and temperature conditions. In such regard, as for the Earth, laboratory mineral-physics and petrology experiments at high pressure and temperature are of primary importance.
Inversion of seismology and geodesy data to infer mantle composition and thermal profile, depends upon internal density, velocity and rheology, which in turn depend upon thermo-elastic and visco-elastic properties of constituent materials at relevant thermodynamic conditions. As of today, we lack the necessary knowledge concerning the minerals comprising the mantle of Mars.
Thus, this research project aims at the determination of the sound wave velocities and acoustic attenuation of main mineral phases (olivine and its high-pressure polymorphs, ortho- and clino-pyroxenes and garnets) and mineralogical aggregates expected on Mars, as a function of pressure, temperature and chemical composition.
Keywords: seismic velocities, attenuation, high pressure, high temperature, mantle minerals, Mars
We propose to utilize both classic approaches such as combined in-situ ultrasonics, X-ray radiography and X-ray diffraction at high pressure and temperature in multi-anvil press, and more innovative methods combining laser pump-probe picosecond-acoustics with diamond anvil cell and laser heating. Acoustic attenuation measurements by torsional forced-oscillation experiments implemented in a rotational Paris‐Edinburgh press (RoToPEc) will complement the project.
Sound velocity and density determination, together with acoustic attenuation measurements and available thermo-elastic data on mineral phases, will allow establishing a visco-elastic and rheological model of Martian mantle needed to correctly constrain interior structures using seismic data, rotation, and tidal dissipation. In particular, combined with InSight data, these laboratory measurements will allow discriminating between proposed mantle mineralogical composition models and will place constraints on mantle temperature profile.
We are looking for a candidate motivated for experimental and developmental work, self-driven but capable to effectively work in a collaborative environment. Proven experience with measurements at high pressure and high temperature is required, ideally both in large volume presses and in laser-heated diamond anvil cells. Knowledge of mineralogy, elasticity and rheology will be highly appreciated. A PhD in physics, materials science, Earth sciences or a related field is required for this position.
The research activity will be developed within the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) NASA Discovery Program mission, of which D. Antonangeli is co-investigator, and supported by the Centre National d'Études Spatiales (CNES) and by the ERC-funded project PICKLE (Planetary Interiors Constrained by Key Laboratory Experiment), of which D. Antonangeli is the principal investigator. Following the successful Apollo program, InSight is the first extra-terrestrial seismology mission to probe the interior of a telluric planet other than Earth. Hence, this will provide a unique opportunity to improve our knowledge not only of Mars, but also of telluric planets in general.
The research project will be carried out at the Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), a research unit supported by the Centre National de la Recherche Scientifique (CNRS), Sorbonne Université and the Muséum National d'Histoire Naturelle (MNHN), and more specifically within the research team Minéralogie, Pétrologie et Physique Planétaire (MP3, group responsible D. Antonangeli). Acoustic attenuation measurements will be carried out in collaboration with J.P. Perrillat (Lab. de Géologie de Lyon, Université Claude Bernard Lyon 1).
IMPMC counts researchers with competences spanning over condensed matter physics, material science, biology and mineralogy, offering a truly multidisciplinary research setting. IMPMC has historical links with synchrotron facilities and traditional expertise in high-pressure experimentations and diamond anvil cell and large volume press technologies. On site we have access to a complete synthesis laboratory, a double-sided laser-heating diamond-anvil cell laboratory and a large volume laboratory (piston-cylinder, Paris Edinburg presses, multi-anvil press) laboratory, a femtosecond laser micro-machining facility, electronic microscopes (SEM, TEM), a focused ion beam, a NanoSIMS, x-ray diffraction equipment, picosecond acoustics setup, and various optical spectrometers (Raman, infrared, Brillouin spectrometers).
Scientific responsible: Daniele Antonangeli (CNRS, IMPMC)
Constraints and risks
The proposed experimental activity will be carried out at IMPMC and at synchrotron facilities. Access to third generation synchrotron facilities is granted on the basis of competitive proposals but based on the scientific merit of our proposals, our scientific output in high-profile journals, and the personal collaboration with several beamline scientists, the access to synchrotron facilities is not foreseen as limiting factor to the success of the project.
Performing experiments at extreme pressure and temperature conditions is never easy, and the collection of high-quality data requires extreme care in sample preparation, characterization and conditioning, together with stringent measurements and analysis protocols.
Several national and international (USA, Japan) trips have to be expected to perform measurements as well as to participate to meetings and conferences.
Salary and support to research activity are funded by the ERC CoG PICKLE (PI D. Antonangeli).
Preferred starting date is November 2018. The position is immediately open and will remain open until filled. The initial appointment is for 18 months, with possible extension, depending on progress, up to 36 months.
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