Date : 24/01/2012

Laboratory
BioEMCo, geochemistry team
UMR 7618, CNRS / UPMC
4 place Jussieu
75252 Paris cedex 05
Website
Main discipline : Chemistry
Lab director : Luc Abbadie

PhD Supervisor
Sylvie Derenne
email : Cet e-mail est protégé contre les robots collecteurs de mails, votre navigateur doit accepter le Javascript pour le voir
phone: +33 1 44 27 35 14

Subjects
1.: cosmochemistry
2.: carbonaceous meteorite
3.: organic matter

Tools and Methodologies
1.: organic chemistry
2.: chemical analysis
3.: spectroscopy

Summary of lab's interests
Within a highly multidisciplinary lab, the geochemistry team is interested in the processes taking place in the natural environment and their integration in the global biogeochemical cycles. The team is also famous in organic geochemistry and the studied objects encompass soil, riverine water, recent and ancient (until Archaean) sediment and meteorites. Almost all the studies are developed within collaborative networks.

Summary of project
Carbonaceous meteorites are the most primitive objects of the solar system. They contain up to 4% of carbon, mainly occurring as insoluble organic matter (IOM). This IOM contains key information about the organo-synthesis processes taking place in the Solar system, which are so far poorly understood. It is also interesting for exobiology as it contains extra-terrestrial signatures which allow distinguishing it from the oldest terrestrial organic matter. Its chemical structure was recently investigated using a combination of analytical approaches within a consortium of collaborating laboratories, including our team, and led us to propose a model for the IOM chemical structure. A synthesis pathway can be put forward based on this model and the aim of this PhD project is to test it experimentally. To this end, we would like to realize organo-synthesis under conditions compatible with those occurring in the circumstellar disk when the first solids of the solar system formed. The resulting products will then be characterized through the same combination of analytical tools as previously used for the meteorite IOM. The latter involved various spectroscopies, electron microscopy observations and chemical degradations.

Interdisciplinarity of the project
This subject is interdisciplinary as it requires to constrain the synthesis conditions thanks to knowledge in cosmochemistry and to use several methods of chemical analysis. Analysis in organic chemistry is mastered in the host lab and the work will be planned in tight collaboration with a cosmochemistry lab (F. Robert, MNHN) and two additional labs mastering specific techniques such as electron microscopy (J.-N. Rouzaud, ENS Géologie) and electron paramagnetic resonance (D. Gourier, Chimie ParisTech).

Do you have an available funding for this project ?
The project will be supported by the Labex Matisse