Climatic, environmental changes and human impacts in Central Africa over the last 28,000 Years inferred from organic biomarkers

Understanding and forecasting climate variability is a major scientific challenge, particularly in Africa, which has been recognized by the IPCC as one of the most vulnerable continents to climate change. Of key interest is how temperatures, rainfall, fire activity and soil erosion will evolve with increasing greenhouse gas concentrations. From this point of view, reconstructing the abrupt climatic and environmental events that have punctuated the recent history of the African continent is of prime interest to better understand the response of African climate and ecosystems to both external forcing and internal feedbacks. Past studies have shown that African climate, in particular the monsoon, can respond rapidly to gradual insolation changes. However, many issues remain unresolved, such as the timing and spatial expression of major past perturbations associated with the deglaciation and African Humid Period.
The aim of this PhD research is to employ the organic matter preserved in three sedimentary sequences from Cameroon to characterize and quantify climatic changes and anthropogenic impacts over the last 28 ka, notably concerning temperature, precipitation, soil erosion and fire activity. These cores represent ones of the few sedimentary archives on the African continent covering the deglaciation and the Holocene. The candidate will work to characterize the sediments and then develop stratigraphic records based on an extensive organic geochemical toolbox, potentially including: Rock-Eval, glycerol dialkyl glycerol tetraethers (GDGTs) and compound-specific δD for quantitative assessment of continental temperatures, precipitation and erosion, respectively, levoglucosan as a proxy of past fire dynamics, and coprostanol as an indicator of human presence. The research will include organic geochemistry laboratory work, possibly fieldwork (depending on the candidate), and frequent interactions with researchers from other institutions (sedimentologists, mineral geochemists, and archeologists) involved in this interdisciplinary project.

Keywords: Organic Geochemistry, Environmental changes, African Climate changes

• Academic supervisor    Prof. Guillemette MÉNOT, LGLTPE-ENS de Lyon, ORCID : 0000-0003-2423-8294
• Doctoral School    ED 341 E2M2, École Normale Supérieure de Lyon, Université de Lyon
• IFPEN supervisor    Dr David SEBAG, ORCID : 0000-0002-6446-6921
• PhD location    École Normale Supérieure de Lyon (LGLTPE), Lyon, France
• Duration and start date    3 years, starting in the fourth quarter 2024 (Novembre 4)
• Employer    IFPEN
• Academic requirements    University Master degree in Earth Sciences or Chemistry     
• Language requirements    English level C1 (CEFR)
• Other requirements    Academic achievements, Past research experience (internships, master thesis), Interest to work in a multidisciplinary research environment, Communication skills

To apply, please send your cover letter and CV to the IFPEN supervisor indicated below.