Tunisian dust records across the MIS 5-4 transition
Swiss partners
-
Université de Lausanne: Christoph Schmidt
MENA partners
-
Institut National de Recherche et d'Analyse Physico-chimique: Hajer Mejri
Other partners
- Institute of Geography, Ruprecht-Karl University of Heidelberg (Germany): Sebastian Kreutzer
Presentation of the project
The Marine Isotope Stage (MIS) 5a to 4 transition (82,000–71,000 years ago) represents a critical paleoclimatic shift from interglacial to glacial conditions during the last Ice Age. This transition, identified through oxygen isotope variations in marine sediments reflecting global ice volume changes, was characterized by abrupt cooling, sea level fall (20–30 m), and enhanced Saharan dust emissions due to increased aridification. Southern Tunisia’s loess deposits – windblown dust accumulations preserving paleoenvironmental signals – provide an exceptional terrestrial archive of these changes. The Matmata Plateau sequences in particular record dust provenance shifts reflecting atmospheric circulation reorganization during this transition. Understanding these dust-climate interactions is crucial for predicting how modern dust emissions may respond to climate change, given dust’s significant impacts on Earth’s radiation balance and ocean biogeochemistry.
Goal: Reconstruction of atmospheric dust circulation patterns over North Africa during MIS 5a–4 by tracing the origin (provenance) of Tunisian loess using luminescence fingerprinting, complemented by geochemical-mineralogical analyses.
Field and laboratory methods: INRAP (Tunis): Sediment source characterization by X-ray fluorescence (XRF) for bulk geochemistry, X-ray diffraction (XRD) for crystallography and mineralogy, grain-size analysis and carbonate content (provenance). University of Lausanne (UNIL): Luminescence fingerprinting of Tunisian loess, to identify its source (Grand Erg Oriental vs.Western corridors) by measuring their unique luminescence signatures.
Validation: against published regional isotopic (Sr-Nd) data and paleoclimate data
Relevance and impact:
- Climate relevance: Deciphers how dust sources and wind regimes responded to climate shifts during the MIS 5a–4 transition
- Feasibility: Focused 1-year workflow benefiting from INRAP’s sediment-analytical expertise and UNIL’s luminescence specialization
- Partnership synergy: combines INRAP’s regional knowledge with UNIL’s provenance methods
- Long-term value: Establishes a Swiss-Tunisian collaboration (UNIL-INRAP) with shared protocols, training early-career researchers in cutting-edge luminescence applications, regional geology and sedimentology