PhD opportunities

Climatic and tectonic forcing on the development of syn-orogenic carbonate platforms in foreland basins: examples from the Western Alps and the Pyrenees

Thesis proposal

Area of expertiseGeoscience and Geoengineering
Doctoral SchoolGťosciences, Ressources Naturelles et Environnement
SupervisorM. Damien HUYGHE
Co-supervisorMme Caroline MEHL
Research unitCentre de Gťosciences
ContactHUYGHE Damien
Starting dateOctober 1st 2022
Keywordscarbonates, foreland basins, sedimentology, climate, tectonics
AbstractStudying syn-orogenic sediments is of primary interest to constrain orogen dynamics, as they record the complex interactions between the growth of the orogenic wedge, isostatic adjustment, eustatic sea level variations, surface processes and climate change. Numerous studies dealing with the foreland basins stratigraphy focused on siliciclastic deposits. Syn-orogenic carbonate platforms, even if recording a significant part of the history of foreland basins, have been poorly studied until now.
Syn orogenic sedimentation begins with carbonates deposition on the distal edge of the foreland basin, lying unconformably on the pre-orogenic series. The demise of the carbonate ramps is classically attributed to the drowning of the carbonate depozone, in response to increasing tectonic loading and subsidence of the basin. First order proxies are thus tectonic ones. Such models rely on a strong assumption: they consider climatic conditions as stables and homogeneous.
Nonetheless, Alpine as well as Pyrenean carbonate platforms disappeared synchronously with first order climate changes: the Eocene-Oligocene limit for the Alps, the Lutetian-Bartonian limit for the Pyrenees.
We thus propose to re-investigate the tectono-stratigraphic evolution of the Alpine and Pyrenean foreland basins, reconsidering the role of climate settings on onset and demise of the carbonate ramps. As both basins include the same fauna and stratigraphically evolve in the same way but under a different timing, their comparison will allow to determine if they underwent common forcing mechanisms.
A multi-tools approach will be used to solve the problem:
1- Field work will be performed to investigate the carbonated facies and their transition to siliciclastic ones. On each section, sedimentary facies as well as fossils associations will be described both in the field and thin section. In collaboration with paleontologists, Shallow benthic macro foraminifera index species will be correlated to the Shallow Benthic Biozones.
2- A multi-scale approach will be used to test the impact of tectonism on the stratigraphical record. Local scale impact will be deduced from micro-fracturing analysis whereas establishment of subsidence curves will help understanding processes at basinal scale.
ProfileThe candidate should have a strong background in sedimentary geology, micropaleontology and structural geology. This subject will require both a taste for field and laboratory work. Good writing and speaking skills, in French and English, as well as a taste for teamwork will be essential to successfully complete this project.

How to apply
Candidates must contact the director(s) of the thesis proposal or the contact person specified. The latter will then hold auditions and select the most suitable candidate for their project.
Content of the application :
-a CV
-a letter of motivation
-transcript of marks of Master 2 (or equivalent)
-summary of the Master 2 report (or equivalent)
-Letter of recommendation from the Master 2 internship supervisor (or equivalent)
FundingConcours pour un contrat doctoral