A1 Journal article (refereed)
Morphology‐Dependent Magnetic Properties in Shallow‐Water Ferromanganese Concretions (2024)

Wasiljeff, J., Salminen, J. M., Roberts, A. P., Hu, P., Brown, M., Kuva, J., Lukkari, S., Jolis, E. M., Heinsalu, A., Hong, W., Lepland, A., Suuroja, S., Parkkonen, J., & Virtasalo, J. J. (2024). Morphology‐Dependent Magnetic Properties in Shallow‐Water Ferromanganese Concretions. Geochemistry, Geophysics, Geosystems, 25(5), Article e2023GC011366. https://doi.org/10.1029/2023gc011366

JYU authors or editors

Publication details

All authors or editors: Wasiljeff, Joonas; Salminen, Johanna M.; Roberts, Andrew P.; Hu, Pengxiang; Brown, Maxwell; Kuva, Jukka; Lukkari, Sari; Jolis, Ester M.; Heinsalu, Atko; Hong, Wei‐Li; et al.

Journal or series: Geochemistry, Geophysics, Geosystems

ISSN: 1525-2027

eISSN: 1525-2027

Publication year: 2024

Publication date: 16/05/2024

Volume: 25

Issue number: 5

Article number: e2023GC011366

Publisher: Wiley-Blackwell

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1029/2023gc011366

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/94919

Abstract

Ferromanganese concretions commonly occur in shallow-water coastal regions worldwide. In the Baltic Sea, they can record information about past and present underwater environments and could be a potential source for critical raw materials. We report on their microstructural characteristics and magnetic properties and link them to their formation mechanisms and environmental significance. Microstructural investigations from nano- and micro-computed tomography, electron microscopy, and micro-X-ray fluorescence elemental mapping reveal diverse growth patterns within concretions of different morphologies. Alternating Fe- and Mn-rich growth bands indicate fluctuating redox conditions during formation. Bullet-shaped magnetofossils, produced by magnetotactic bacteria, are present, which suggests the influence of bacterial activity on concretion formation. Spheroidal concretions, which occur in deeper and more tranquil environments, have enhanced microbial biomineralization and magnetofossil preservation. Conversely, crusts and discoidal concretions from shallower and more energetic environments contain fewer magnetofossils and have a greater detrital content. Our results provide insights into concretion formation mechanisms and highlight the importance of diagenetic processes, oxygen availability, and bacterial activity in the Baltic Sea.

Keywords: minerals; manganese; iron; mineralisation; bacteria; fossils; magnetic properties; microstructures

Contributing organizations

Ministry reporting: Yes

Preliminary JUFO rating: 2