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PhD thesis offer in geology/geochemistry - (M/F)

This offer is available in the following languages:
- Français-- Anglais

Date Limite Candidature : vendredi 15 mars 2024

Assurez-vous que votre profil candidat soit correctement renseigné avant de postuler

Informations générales

Intitulé de l'offre : PhD thesis offer in geology/geochemistry - (M/F) (H/F)
Référence : UMR7358-RAPPIK-001
Nombre de Postes : 1
Lieu de travail : VANDOEUVRE LES NANCY
Date de publication : mercredi 31 janvier 2024
Type de contrat : CDD Doctorant/Contrat doctoral
Durée du contrat : 36 mois
Date de début de la thèse : 1 septembre 2024
Quotité de travail : Temps complet
Rémunération : 2 135,00 € gross monthly
Section(s) CN : Earth and telluric planets: structure, history, models

Description du sujet de thèse

Project Title: Processes controlling concentrations of volatile elements in fluids associated with magmatic segments along the East African Rift – implications for the co-production of economically viable elements (i.e., He, H) within geothermal systems.

Supervisors: Raphaël Pik (CNRS – Université de Lorraine, raphael.pik@univ-lorraine.fr), David Bekaert (Université de Lorraine)

Co-supervisors: Nicolas Bellahsen & Isabelle Moretti (Sorbonne Université)

General framework: This doctoral position is part of the European-based Marie Sklodowska-Curie Actions Doctoral Network TALENTS (https://www.talents-dn.eu). TALENTS aims at training early career researchers with an interdisciplinary, science-driven approach to develop new sustainable solutions for global challenges associated with the energy transition. We focus on continental rifts, which are key regions for geothermal energy, carbon capture and storage, new resources such as native hydrogen and helium, as well as endangered human habitats due to geohazards such as earthquakes and volcanic activity. TALENTS fuses research and training at 18 European institutes and academic partners, as well as 11 companies that are actively involved in the energy transition. The doctoral network is centered around 12 individual PhD projects addressing fundamental scientific aspects of rift system processes, collectively bridging several orders of magnitude of spatial and temporal scales. Each doctoral candidate is linked to a second academic partner to complement and broaden their scientific training and to a dedicated industry partner to acquire industry-relevant skills and preview possible non-academic career paths.

Specific objectives: this PhD project is part of the TALENTS project, as DC10 in the WP3 (https://www.talents-dn.eu).

The East African Rift system possess geothermal resources of high value, mainly linked to the vertical transfer of magmas through Earth's crust. Besides some high-temperature geothermal systems, which are exploited to provide electricity, this widespread source of energy remains largely underexploited along the rift system. While a key aspect for the energy and ecology transitions resides in the use of such sustainable resources, their operational exploitation is often compromised by non-economically viable costs, especially in the local socio-economic context, therefore hampering African communities to benefit from this important potential resource. In the meanwhile, the co-production of several additional natural resources associated with the geothermal systems of the east-African rift may represent another promising avenue to increase their exploitation profitability. In this framework, strategic volatile elements such as helium and hydrogen are economically relevant candidates that could be co-produced along with geothermal energy. The concentration of these volatile elements in natural hydrothermal systems can however greatly vary due to the large variety of processes taking place between magmas and crustal environments, as well as processes of fractionation during water-gas interactions in the subsurface.

The objective of the project is to make a case study along the East African Rift system of co-association of geothermal energy and strategic elements such as He and H2 by (1) documenting the elementary flux of hydrothermal fluids and associated volatiles along various segments of the East African Rift, (2) investigating and understanding the processes that control potential isotopic enrichments and concentration gradients, and (3) providing information for future evaluation of local production implantation.

Based on a general and standard approach of geochemical fluids characterization of gas seepages along the rift (concentrations and isotopic compositions of main volatile species), particular emphasis of the PhD project will be placed within designated sites on the use of new approaches for high-precision measurement of heavy noble gas isotopic compositions in order to quantify processes occurring during water-gas interactions along the upward migration of fluids (Byrne et al., 2021, Bekaert et al., 2023). This geochemical approach will be principally conducted at CRPG – Nancy (https://crpg.univ-lorraine.fr) where the PhD candidate will be based and principally advised. The local tectono-magmatic context of selected site will also be investigated in collaboration with ISTEP - Sorbonne University – Paris where the PhD candidate will be co-advised (http://istep.upmc.fr/fr/index.html). Exploration and sampling at selected natural sites and/or geothermal exploitation sites along the East African Rift will be conducted within the framework of international collaborations with scientists and local companies from African countries.

Main results expected from this PhD project: (1) a detailed spatial characterization of volatile fluxes associated with geothermal systems along the East African Rift (mainly from Afar to Tanzania, in the eastern branch), (2) a new understanding of the patterns of volatile element migrations within hydrothermal fluids (i.e. He, H), in connection with the structural and magmato/volcanic context, (3) a comprehensive description of the processes that control such concentration gradients along the upward pathway of fluids through interactions with the magmatic plumbing system and the surrounding crust, (4) novel insights into future potential exploitation.

Potential candidates for this PhD project must possess a strong basis in isotopic geochemistry, and preferentially noble gas geochemistry. Candidates will have to develop and build upon existing analytical apparatus on site and in the laboratory, and perform a substantial amount of gas analyses and noble gas isotope measurements using in-house mass spectrometers. Previous experience with such analytical activities will therefore represent a strong asset.

References:
D. V. Bekaert, P. H. Barry, M. W. Broadley, D. J. Byrne, B. Marty, C. J. Ramírez, J. M. de Moor, A. Rodriguez, M. R. Hudak, A. V. Subhas, S. A. Halldórsson, A. Stefánsson, A. Caracausi, K. G. Lloyd, D. Giovannelli, A. M. Seltzer, Ultrahigh-precision noble gas isotope analyses reveal pervasive subsurface fractionation in hydrothermal systems. Sci. Adv.9, 2023, DOI:10.1126/sciadv.adg2566

D.J. Byrne, M.W. Broadley, S.A. Halldórsson, E. Ranta, A. Ricci, R.L. Tyne, A. Stefánsson, C.J. Ballentine, P.H. Barry, The use of noble gas isotopes to trace subsurface boiling temperatures in Icelandic geothermal systems, Earth and Planetary Science Letters, Volume 560, 2021, 116805, https://doi.org/10.1016/j.epsl.2021.116805.

Academic secondment: University of Florence and CNR, Derek Keir and Giacomo Corti, 2 months year 2, for comparison of hydrothermal fluids composition and spatial variations with structural and seismic context along the Ethiopian rift segments.

Industry secondment: 45-8 Energy company. Metz – France (https://458energy.com/home/), 3 months in year 3 to make a synthesis and evaluate exploitation potentials.

Enrolment in Doctoral degree: Université de Lorraine (http://doctorat.univ-lorraine.fr/en/doctoral-schools/sirena)

Employer : CNRS

Fixed-term: 3 years

Principal contact for information: raphael.pik@univ-lorraine.fr

Application: The available positions is free to apply for, given that the following criteria defined by the EU are fulfilled by the applicant:
- All researchers recruited in a doctoral network must be Early-Stage Researchers (ESRs; i.e., be in the first four years (full-time equivalent research experience) of their research careers and have not been awarded a doctoral degree).
- Researchers can be of any nationality.
- Mobility Rule: at the time of recruitment by the host organisation, researchers must not have resided or carried out their main activity (work, studies, etc.) in the country of their host organisation (i.e. France in the case of this PhD advertisement) for more than 12 months in the 3 years immediately prior to the reference date. Compulsory national service and/or short stays such as holidays are not taken into account. The mobility rule applies to the (first) beneficiary where the researcher is recruited, and not to beneficiaries to which the researcher is sent or seconded. It is also only determined at one point in time: that of the fellow's first recruitment in the project.

Application must only be submitted on line following this specific link

Applications need to include:
(1)A motivation statement,
(2)statement of research interests,
(3)career vision,
(4)curriculum vitae,
(5)academic credentials (mark sheets and degree statements),
(6)short abstract of the MSc thesis or equivalent, and
(7)the names and contact details of two referees.
Applicants can apply for a maximum of 2 PhD positions for the Marie Sklodowska-Curie Actions Doctoral Network TALENTS (https://www.talents-dn.eu), motivating and ranking their choices

Application deadline: 15th March 2024

Start date: 1st September 2024

Contexte de travail

CRPG – Nancy (https://crpg.univ-lorraine.fr)