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Presence of biogenic magnetite in ferromanganese nodules
Author(s) -
Hassan Muhammad Bin,
Rodelli Daniel,
Benites Mariana,
Abreu Fernanda,
Murton Bramley,
Jovane Luigi
Publication year - 2020
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12831
Subject(s) - magnetite , ferromanganese , diagenesis , geology , mineralogy , remanence , precipitation , nodule (geology) , magnetic mineralogy , manganite , geochemistry , manganese , magnetization , materials science , metallurgy , paleontology , ferromagnetism , physics , quantum mechanics , meteorology , magnetic field
Summary Transmission electron microscopy (TEM) and rock magnetic study of ferromanganese nodule sample JC120‐104B collected from Clarion‐Clipperton zone (CCZ) in the eastern Pacific Ocean indicate the presence of biogenic magnetite (magnetofossils). First‐order reversal curves (FORCs) and decomposition of isothermal remanent magnetization (IRM) curves were used as the main tool for the characterization of magnetic properties of the bulk magnetic minerals present in the sample. TEM was performed for the direct identification of biogenic magnetic minerals (magnetofossils). The nodule sample has distinctive alternating Mn and Fe‐rich layers per micro‐X‐ray fluorescence data. While diagenetic precipitation of Mn is known for the less oxygenated environment, the presence of biogenic magnetite is also common in the environments where the supply of oxygen is limited. Moreover, the increase in magnetic properties is consistent with the increase in Mn‐content, which is related to favourable conditions for Mn precipitation as well as magnetite biomineralization in oxic‐suboxic transition zone. Investigations on magnetofossil fingerprints lead to a better understanding of paleoenvironmental conditions involved in the formation and growth of deep‐sea ferromanganese nodules.