PhD thesis on Opening mechanisms of the West European Cenozoic Rift System (ECRIS) H/F
BRGM, the French geological survey, is France’s leading public institution in Earth Sciences, bringing together 1000 experts and passionate people, spread over 29 entities in French metropole and overseas territories. The main objective of BRGM’s activities is the continuous improvement of geological knowledge with the aim of responding to current social and environmental challenges by carrying out innovative projects on resources management and global sustainable development. Through partnerships with numerous public and private stakeholders, it focuses on scientific research, providing scientifically-validated information to support public policies and international cooperation
Rift systems are priority targets for deep geothermal energy (faulted and deep system), however the investment cost associated with deploying this energy is very high and the knowledge on reservoir geometry is often very local, generating failures. Recent studies (Faulds et al, 2006; 2009; Moeck, 2014; Ingebritsen and Gleeson, 2015) show that the geometries of geological formations and especially fault networks have a fundamental impact on the ability to conduct or stop geothermal fluids. Such investigations need to be carried out upstream, and at the scale of the rift system, in order to better understand the reservoirs, what’s more when the ambition is to exploit several relatively close sites.
This thesis focuses on the West European Cenozoic Rift System (ECRIS), a potential target for geothermal exploration in France. The area of interest includes the Rhine and Bresse rifts, as well as the Rhine-Saône transfer zone that links these two segments. Several mechanisms of ECRIS opening have been invoked in the literature (extension vs. transtension). Currently published models suggest either a large-scale global transtensional opening in a N-S compressive context (Chorowicz and Deffontaines, 1993; Bourgeois et al., 2007), or a composite dynamic evolving from a NE-SW transtensional context to an E-W to WNW-ESE extension (Rocher et al, 2003), or more classically an E-W to ESE-WNW extension of Oligocene age (Villemin and Bergerat, 1987; Larroque and Laurent, 1988, Bergerat, 1985; 1987; Schumacher, 2002). Work by Briais et al. (2017) has recently revealed a transtensional opening in the Rhine Graben, much earlier than previously expected and of Upper Eocene age. According to the literature, the Rhine Graben was then controlled by N-S compressive constraints, producing local geometries consistent with low extension rates (Bourgeois et al., 2007).
This lack of consensus indicates the need to revisit the structural and sedimentary geometries of the ECRIS using proven methods but guided by an integrative approach, and coupling new methods constraining the temporality of fault movements and the nature of fluids that have circulated in the fracture networks. The PhD thesis work will follow an integrative multi-scale approach and will combine seismic profile analysis, analyses of faults and fractures in the field and in drill cores, micro-structural and petrophysical analyses of fault rock thin sections, with U-Pb absolute dating on calcitic fault and fracture mineralizations. These results will be compared with IFPEN’s analogue modelling database, in order to develop new analogue experiments dedicated to the problem.
This work will benefit from the dynamics of the ANR GLITER (Integrative multiscale investigation of heat and lithium source and pathways in Deep Geothermal System in a rift context: Focus on the Upper Rhine Graben, submitted April 2021). A part of the thesis will involve a work of hierarchization of the fault systems, in view of their hydraulic impact, which will be used within the task ‘Structural control on hot fluid circulation’ of the ANR GLITER.
You are graduated from a master degree in sciences and you are looking for a Phd thesis.
You will mobilise the following skills and qualities:
In addition to basic knowledge of Earth Sciences, this research project requires an ability for acquiring and integrating data from several disciplinary fields. Experience in this direction is very welcome (e.g. a Master’s degree combining two of the following fields: geodynamics, sedimentation, faulting in the brittle crust), but applications with a mono-disciplinary experience and a strong motivation to acquire other skills during the thesis are also encouraged. A collaborative spirit and an ability for teamwork are required. Motivation to broaden the implications of this work to the field of fluid flows in faulted media is a plus.
The writing of scientific papers in English, the presentation of results in workshops and international conferences, are an integral part of the thesis work.
Localisation du poste
France, Centre-Val de Loire, Loiret (45)
Spécificité du poste
This thesis is directed by the University of the Sorbonne with co-supervision by the BRGM, IFPEN and the Paris-Saclay University.
In a favourable environment with work-life balance, you will appreciate the climate of benevolence and friendliness that characterises BRGM.
In addition, we support you in your professional career and offer you support systems to continue to develop your skills, in particular through professional training. At BRGM, you will benefit from several advantages such as remuneration based on 13 months, generous holiday allowance, time in lieu, a company restaurant, sports facilities, vacation and leisure services, etc.
BRGM guarantees a total transparent and fairness recruitment procedure.
To apply, send us your application (curriculum vitae and a cover letter) before 30/05/2021.
Please note that all our positions are open to people with disabilities.
We will study your application as soon as the submission deadline has passed. If your application is successful, we will contact you for recruitment interviews during which you will discuss with the recruiting operational division, the human resources department and a third transversal department.
To learn more about de thesis, you can write to HOMBERG Catherine, Phd thesis director (firstname.lastname@example.org)