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Intitulé du poste : master internship
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Laboratoire/Institut : Laboratory of Planetology and Geosciences
Description du poste : HIGH PRESSURE CLATHRATE HYDRATES IN LARGE OCEAN WORLDS Icy satellites of Jupiter and Saturn are the only extra-terrestrial planetary bodies where the presence of liquid water has been discovered in a form of subsurface oceans. Subsurface oceans are nowadays the most appealing astrobiological targets and became the focus of diverse interdisciplinary research as well as of upcoming space missions. While a variety of volatile compounds (CO2, CH4, N2, NH3, CH3OH, etc) are expected to be present in significant amount in the oceans of icy satellites of Saturn and Jupiter, they should be stable in the form of gas clathrate hydrates at relevant high-pressure and from low- to temperate-temperature conditions. Clathrate formation and destabilization govern the volatile reservoir and chemical exchange in the interior, and have a major impact on the ocean composition, evolution and astrobiological potential. Despite being the main reservoir of volatiles in large ocean worlds, our knowledge on stability and properties of chemically relevant clathrate hydrates at relevant thermodynamic conditions is very limited. Existing data at high pressure rely on clathrate hydrate composed of a single gas guest (CO2, CH4, N2, etc), while we know that in nature clathrate hydrate should be composed of multiple gas guest which may have major implications for the chemical evolution of many ocean worlds (Titan, Pluton, Europa, Ganymede, Callisto). The goal of the internship is to explore the stability and structure of clathrate hydrates from the system CH4-CO2-H2O in a wide range of pressures and compositions by using in situ Raman spectroscopy and X-Ray diffraction available at Laboratory of Planetology and Geosciences (LPG, Nantes) and European Synchrotron Radiation Facility (ESRF, Grenoble), respectively. The workflow will consist in (i) preparing pure CH4 and CO2 clathrates to test the gas loading system and confirm previously reported dissociation curves (LPG, Nantes); (ii) preparing mixed CH4-CO2 clathrates from gas mixtures, testing different loading procedure in a diamond anvil cell (high-pressure generation device) and controlling the composition of loaded samples (LPG, Nantes); (iii) determination of the molar compositions in synthesized clathrate samples using combined Raman spectroscopy and gas chromatography (LPG, Nantes); (iv) performance of in situ high-pressure X-Ray diffraction (ID27 beamline of ESRF, Grenoble). Most of the experimental work will be done at LPG with 2-3 short trips to ESRF. The internship is a part of the ANR PRC project “CAGES” (coord. A. Pakhomova) that is run in collaboration between LPG and ESRF. The internship is funded up to six months with a stipend of ~600 euros/month (additional stipend can be granted to candidates outside France). Depending on the performance, after the internship and accomplishment of the Master studies, the student can undertake a PhD position at ESRF starting September 2024 and will be integrated in the Graduate Programme in Earth and Planetary Sciences at Nantes Université. The PhD project will focus on investigation of extended compositions of mixed clathrate hydrates at low-temperature and high-pressure using in situ Raman spectroscopy and X-Ray diffraction. Further information may be obtained from Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. or Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser.
Durée du contrat : up to 6 months
Date de prise de fonction : 2024-02-01
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