#ferromanganese

Centennial to millennial-scale paleoenvironmental record from a coastal iron-manganese concretion - Communications Earth & Environment Seven thousand years of environmental variability are recorded by a coastal iron-manganese concretion, according to microstructure, magnetic, geochemical, and isotopic geochemical analyses of a concretion from the Baltic Sea.

📣Highest-resolution #geochronology ever reconstructed for a #ferromanganese concretion

🧪We combined #¹⁴C, anthropogenic Pb and Co-chronometer techniques in a Bayesian age model

🌊Ce-anomaly, δ56Fe and magnetic mineralogy record variability in the Baltic Sea over 7000 years

doi.org/10.1038/s432...

Synchrotron-µ-XRF maps showing Fe (red) and Mn (green) distributions in (a) discoidal, (b) crust, and (c) spheroidal concretions from the Baltic Sea. The white scale bars equal 500 µm. Original reference: Wasiljeff et al. 2025: Mineral phases and growth conditions of morphologically diverse shelfal ferromanganese concretions. Geochimica et Cosmochimica Acta 400, 227–247, https://doi.org/10.1016/j.gca.2025.05.012

🧪New article on the mineralogy of Baltic Sea #ferromanganese concretions
🌊Mn layers are birnessite with microbially-mediated dendritic texture. Fe layers are ferrihydrite with admixed detrital grains; the layers remain after the dissolution of birnessite.
RCF #Fermaid project
doi.org/10.1016/j.gc...

Overlay computed tomography image of the edge of a ferromanganese concretion. The bright patches are ferromanganese material that precipitated during a 12 weeks laboratory experiment. Reference: Majamäki, R., Wasiljeff, J., Purkamo, L., Hultman, J., Asmala, E., Yli-Hemminki, P., Jørgensen, K., Koho, K., Kuva, J. & Virtasalo, J.J. 2025: Microbially-enhanced growth and metal capture by ferromanganese concretions in a laboratory experiment. Geobiology 23, e70010.

🧪It is possible to grow #ferromanganese concretions in the laboratory.

🔬The bright patches at the edge of a concretion in the tomography image precipitated during a 12-week laboratory experiment.

⚗️The ferromanganese growth captured Co, V, Ni, Zn, and Mo from solution.

RCF #FERMAID project

Scanning transmission electron microscope image of a magnetite magnetosome from a Baltic Sea ferromanganese concretion (Wasiljeff et al. 2024, Geochemistry, Geophysics, Geosystems).

Magnetotactic bacteria in the Baltic Sea #ferromanganese concretions produce bullet-shaped magnetosomes.🧪

The magnetosomes are spherical or cubic in the oceanic ferromanganese nodules.

RCF #FERMAID project

Full article:
agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Microbially Enhanced Growth and Metal Capture by Ferromanganese Concretions in a Laboratory Experiment The growth and metal enrichment of ferromanganese minerals on the seafloor have intrigued many studies, yet the role of microbes in the process has remained elusive. Here, we assessed the microbial i...

NEW ARTICLE🧪

🧫Growth of a #ferromanganese concretion in the lab is documented for the first time by micro-CT.

📊The growing concretion captured trace metals (Co, V, Ni, Zn, Mo) from solution.

SLTS #FeCoVERY project
RCF #FERMAID project
@finmari-ri.bsky.social

dx.doi.org/10.1111/gbi....