New constraints on elemental and Pb and Nd isotope compositions of South American and Southern African aerosol sources to the South Atlantic Ocean

• Published in: Geochemistry
• Main Authors: Khondoker, R., Weiss, D., van de Flierdt, T., Rehkamper, M., Kreissig, K., Coles, B.J., Strekopytov, S., Humphreys-Williams, E., Dong, S., Bory, A., Bout‑roumazeilles, Viviane, Smichowski, P., Cid-Agüero, P., Babinski, M., Losno, R., Monna, F.
• Other Authors: Department of Earth Science and Engineering Imperial College London, Imperial College London, The Natural History Museum London (NHM), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ), Comisión Nacional de Energía Atómica ARGENTINA (CNEA), Universidad de Magallanes (UMAG), Instituto de Geociências São Paulo, Universidade de São Paulo = University of São Paulo (USP), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Archéologie, Terre, Histoire, Sociétés Dijon (ARTeHiS), Ministère de la Culture et de la Communication (MCC)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), This study was supported by the NERC grant NE/H005390/1. We would like to acknowledge the CLIM-Amazon project for their financial support of RK (GA no. 295091–project Inco-LAB FP7 supported by the EC).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Isotopic and elemental composition; Source characterisation; Geochemical assessment; Aerosol; South America; Southern Africa; South Atlantic Ocean; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Patagonia
• Online Access: https://hal.science/hal-02347537; https://hal.science/hal-02347537/document; https://hal.science/hal-02347537/file/1-s2.0-S0009281916301465-main.pdf; https://doi.org/10.1016/j.chemer.2018.05.001

International audience Improving the geochemical database available for characterising potential natural and anthropogenic aerosol sources from South America and Southern Africa is a critical precondition for studies aimed at understanding trace metal controls on the marine biogeochemical cycles of the South Atlantic Ocean. We here present new elemental and isotopic data for a wide range of sample types from South America and Southern Africa that are potentially important aerosol sources. This includes road dust from Buenos Aires and lichen samples from Johannesburg, soil dust from Patagonia, volcanic ash from the Andean volcanic belt, and aerosol samples from São Paulo. All samples were investigated for major (Al, Ca, Fe, Mg, Na, K, Mn) and trace element (Cd, Co, Cr, Cu, Ni, Pb, REE, Sc, Th, Y, V, Zn) concentrations and Nd and Pb isotopic compositions. We show that diagrams of 208Pb/207Pb vs. εNd, 208Pb/207Pb vs. Pb/Al, 1/[Pb], Zn/Al, Cd/Al, Cu/Al, and εNd vs. Pb/Al, and 1/[Nd] are best suited to separate South American and South African source regions as well as natural and anthropogenic sources. A subset of samples from Patagonia and the Andes was additionally subjected to separation of a fine (<5 μm) fraction and compared to the composition of the bulk sample. We show that differences in the geochemical signature of bulk samples between individual regions and source types are significantly larger than between grain sizes. Jointly, these findings present an important step forward towards a quantitative assessment of aeolian trace metal inputs to the South Atlantic Ocean.