Postdoctoral position in experimental geochemistry - ANR atmofossil

Description

Job Offer: Postdoctoral Position in Experimental Geochemistry

Project: Tracking the signature of atmospheric organic matter in the oldest geological record: an experimental benchmark.

Hosting laboratory: Laboratoire de Géologie de Lyon (LGL-TPE), ENS Lyon, France.

Duration: One-year position starting in January 2025, with the possibility of up to two renewals.

Gross salary: 2,750 – 3,500 € per month depending on experience. Salaries include Health and Retirement benefits.

Context:

The timing of the emergence of life and its early evolutionary stages on Earth remains enigmatic. Organic matter preserved in Archean (4.0-2.5 Ga) sedimentary rocks may hold key information to document these early stages of biological evolution. Documenting the earliest organic fossil record has proven to be difficult so far. Challenges in identifying organic traces of early life activity in the rock record stem from two primary factors: (1) abiotic processes have supplied the early Earth surface environments with significant amounts of organic matter, (2) the geological history of Archean rocks has structurally and chemically transformed organic matter.

Abiotic organic hazes could have been an important, if not the most important, source of organic matter on the Archean Earth. Yet, little is known about their transformations during geological burial, and, hence, about their possible signatures in Archean rocks.

Objectives:

This project is part of the new strategies that need to be implemented for distinguishing biotic from abiotic organics in the oldest rock record, and mitigate controversies about traces of early life activity. The proposed research includes two objectives: [1] the synthesis of analogues of Archean atmospheric organics through cold plasma discharge experiments and [2] their exposition to simulated geological burial processes in diamond anvil cells (DAC). Their morphological and geochemical transformations will be documented using a combination of spatially-resolved techniques (Raman spectroscopy, SEM/TEM, STXM-XANES spectroscopy).

Working Environment:

Plasma syntheses (objective 1) will be conducted in collaboration with researchers from LATMOS, Guyancourt, France. DAC experiments (objective 2) will be located at the LGL-TPE, ENS Lyon, France (https://lgltpe.fr/acces-et-contacts/). The project will be supervised by J. Alleon (LGL-TPE).

Essential qualifications:

• PhD in Geochemistry or a related field.
• Experience in analyzing organic matter and/or conducting pressure-temperature experiments.
• Expertise in microscopy and/or spectroscopy analyses using SEM and TEM and/or Raman spectroscopy.
• Strong collaborative skills and ability to work within an interdisciplinary team.

Application:

ENS Lyon is committed to promoting diversity and inclusivity. We encourage applications from all qualified individuals, including those from underrepresented groups in Earth sciences. Candidates are welcome to contact Julien Alleon (julien.alleon@ens-lyon.fr) for further information. Application forms should be sent before October 1st, 2024, and contain a cover letter, a CV with a list of publications, and the names and contact information of 2-3 references.