Magnetic analyses of ODP Hole 119-738B sediments ...

• Main Authors: Roberts, Andrew P, Florindo, Fabio, Villa, Giuliana, Chang, Liao, Jovane, Luigi, Bohaty, Steven M, Larrasoaña, Juan C, Heslop, David, Fitz Gerald, John D
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2011
• Subjects: Drilling/drill rig; Leg119; Joides Resolution; Ocean Drilling Program ODP; Southern Ocean
• Online Access: https://dx.doi.org/10.1594/pangaea.788624; https://doi.pangaea.de/10.1594/PANGAEA.788624

Magnetotactic bacteria intracellularly biomineralize magnetite of an ideal grain size for recording palaeomagnetic signals. However, bacterial magnetite has only been reported in a few pre-Quaternary records because progressive burial into anoxic diagenetic environments causes its dissolution. Deep-sea carbonate sequences provide optimal environments for preserving bacterial magnetite due to low rates of organic carbon burial and expanded pore-water redox zonations. Such sequences often do not become anoxic for tens to hundreds of metres below the seafloor. Nevertheless, the biogeochemical factors that control magnetotactic bacterial populations in such settings are not well known. We document the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout Eocene pelagic carbonates from the southern Kerguelen Plateau, Southern Ocean. We provide evidence that iron fertilization, associated with increased aeolian dust flux, resulted in surface water eutrophication in the late ... : Supplement to: Roberts, Andrew P; Florindo, Fabio; Villa, Giuliana; Chang, Liao; Jovane, Luigi; Bohaty, Steven M; Larrasoaña, Juan C; Heslop, David; Fitz Gerald, John D (2011): Magnetotactic bacterial abundance in pelagic marine environments is limited by organic carbon flux and availability of dissolved iron. Earth and Planetary Science Letters, 310(3-4), 441-452 ...