Reconstructing dust deposits originating from potential source ares of Northern Africa - Connecting Late Pleistocene dune archives from the Canary Basin to the Tyrrhenian Basin

• Applicant: Dr. Christopher-Bastian Roettig
• Subject Area: Physical Geography
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 538823399

By the application presented here we aim to correlate aeolianite sequences from the Canary to the Tyrrhenian Basin. The aeolianites are dominated by carbonate sands. The supply of carbonate sand is linked to global sea level. Hence a temporal correlation can be ascribed for the aeolianites of the different sub-areas (Eastern Canary Islands, Southern Spain, Balearic Islands, Sardinia). Several generations of carbonate sands alternate with dust enriched palaeosurfaces. A main aim is to derive dominant source areas of the dust material. In terms of the interpretability at first we have to differentiate between sediment characteristics that result from soil forming processes and those that are inherited from dust input. The interpretation of soil forming processes means the basis for deducing palaeoecological conditions and thus the deposition conditions of dust. Finally, we aim to derive the dynamics of the entire study area. In a final step the data should be used for also modeling future scenarios. The work includes the following questions and methodological approaches that build on one another: I) What are the characteristics of the dust enriched palaeosurfaces within dune archives of the different sub-areas and which palaeoenvironmental conditions are deducible? On the basis of field observations the method of micromorphology, grain size distributions and the analysis of carbonate contents will be used. II) Are there similarities or systemic differences within the aeolianite sequences - especially with regard to amounts and composition of dust input and depositional conditions that can be derived from step I)? Here, primarily the elemental and quartz contents let us distinguish between allochthonous and autochthonous materials (the analyses will be done grain-size-specifically). III) What are the potential source areas of the dust deposits? Are we able to identify specific periods of dominant dust pathways? Therefor the elemental composition and their relations amongst each other build the solid basis for the interpretation. Additionally, the combination of clay mineral spectra and the heavy isotopes Nd, Sr and P (87Sr/86Sr, 206Pb/207Pb and 143Nd/144Nd) are most promising to deduce specific potential source areas. IV) Is it possible to correlate the different sub-areas from the Canary to the Tyrrhenian Basin in terms of their dynamics and periods of dominant dust pathways? Are there patterns against the backdrop of the entire study area? We want to make certain the stratigraphic findings from steps I) - III) by IRSL dating of the dust-enriched palaeosurfaces. To put the results into an overarching context we aim to work out the synchronicities and asynchronicities of dust deposits and site-specific dynamics. In a final step, we want to develop a scenario for the entire study area and use that data for also modelling future scenarios.

• DFG Programme: Research Grants