High-resolution multiproxy analysis of a sediment core from high-elevation lake Bastani


North Africa is the largest source of mineral dust on Earth, which has multiple impacts on the climate system; however, our understanding of decadal to centennial changes in African dust emissions over the last few millenniums is limited. Here, we present a high-resolution multiproxy analysis of sediment core from high-elevation lake Bastani, in Corsica Island to reconstruct past African dust inputs to the Western Mediterranean area over the last 3150 yrs cal BP. Clay Mineralogy with palygorskite and clay ratio associated to geochemical data allows us to identify that terrigenous fluxes are almost exclusively related to atmospheric dust deposition from the West Sahara and Sahel areas over this period. High resolution geochemical contents provide a reliable proxy of Saharan dust inputs with millennial to centennial scale variations. Millennial variations have been correlated to the long term southward migration of the Intertropical Convergence Zone (ITCZ) with an increase of dust input since 1070 yrs cal BP. This correlation suggests a strong link with ITCZ and could reflect the increased availability of dust sources to be mobilized with an increase in wind and a decrease in precipitation over West and North Africa. For centennial to decadal variations, wavelet analyses show that since 1070 yr cal BP, North Atlantic Oscillation (NAO) is the main climatic forcing with an increase of Saharan dust input during positive phase, as suggested by previous study over the last decades. However, when ITCZ is in a northern position, before 1070 yr cal BP, wavelet analyses indicate that total solar irradiance (TSI) is the main forcing factor, with an increase of African dust input during low TSI. With climate reanalysis over the instrumental era, during low TSI we observe a significant negative anomaly in pressure over Africa which is known to increase the dust transport. These two climatic forcing factors (NAO, TSI) modulate Saharan dust inputs to the Mediterranean area at centennial timescale through changes in wind and transport pathways

DOI https://doi.org/10.1594/PANGAEA.910655
Related Identifier https://doi.org/10.5194/cp-16-283-2020
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.910655
Creator Sabatier, Pierre
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2020
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Language English
Resource Type Collection of Datasets; Collection
Format application/zip
Size 7 datasets
Discipline Earth System Research
Spatial Coverage (9.132 LON, 42.066 LAT); Bastani, France