Aluminum extracts in Antarctic paleosols: Proxy data for organic compounds and bacteria and implications for Martian paleosols

• Published in: Sedimentary Geology
• Main Authors: Mahaney, William C., Hart, Kris M., Dohm, James M., Hancock, Ronald G.V., Costa, Pedro, O'Reilly, Shane S., Kelleher, Brian P., Schwartz, Stéphane, Lanson, Bruno
• Other Authors: Quaternary Surveys, School of Chemical Sciences, Dublin City University Dublin (DCU), Department of Hydrology and Water Resources (HWR), University of Arizona, Department of Medical Physics and Applied Radiation Sciences and Department of Anthropology, McMaster University Hamilton, Ontario, Departmento de Geologia, Universidade de Lisboa = University of Lisbon (ULISBOA), Tectonique reliefs et bassins, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Minéralogie et environnements, Funded by Quaternary Surveys, Toronto and the New Zealand Antarctic Programme--KIWI-105. + the Irish Environmental Protection Agency (STRIVE program), the Science Foundation of Ireland (GEOF509) and the Geological Survey of Ireland.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Antarctic and Martian paleosols; Fe-Al extracts; Alp vs. C; Organic proxy data; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Antarctic; Taylor Glacier; New Mountain; Aztec Mountain; Antarc*
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-00680931; https://doi.org/10.1016/j.sedgeo.2011.02.007

International audience Pyrophosphate-extractable Al has been used to establish the presence of organically-complexed compounds in middle latitude and tropical soils and paleosols on Earth. As proxy data used to establish the presence of organic molecules and trace movement within profiles, it has proved an accurate indicator of downward translocation in Spodosols (podzols). Antarctic paleosols, dating from Middle to Early Miocene age (15-20 Ma), are mineralic weathering profiles lacking A and B horizons. These profiles exhibit pavement/Cox/Cz/Cu horizons, largely with sandy silt textures, little clay, and exceedingly low concentrations of organic matter. Recent chemical investigations of 33 soil samples from the New Mountain and Aztec Mountain areas near the Inland Ice, adjacent to the Taylor Glacier, show that pyrophosphate-extractable Al concentrations vary in phase with organic carbon as determined by loss-on-ignition. While Al-extract concentrations in selected samples are low (< 0.15%), increasing values above nil approximately correlate positively with increases in bacterial populations of several common phylum, the extreme high numbers with more advanced biota including fossil Coleoptera. Available data suggest Alp extracts may target samples which may have undergone minor chelation, and which over long periods of time might have a cumulative weathering effect resulting in the accumulation of small concentrations of organic matter.