Magnetic signature of giant magnetofossils

Researchers report a distinct magnetic signature of giant magnetofossils in situ. Giant magnetofossils, the preserved remains of iron-biomineralizing organisms, have thus far been found exclusively in sediments associated with ancient greenhouse climates, suggesting that they are indicators of environmental disturbance. Previously, identifying giant magnetofossils required destructive extraction techniques. Using low-noise, high-resolution magnetic measurements, Courtney Wagner and colleagues identified a component with a high magnetic coercivity signature in a sediment core from Wilson Lake, New Jersey that is distinct from the signatures of conventional magnetofossils that have been previously described. Numerical simulations indicated that this high coercivity signature was consistent with that expected for giant, needle-shaped magnetofossils observed in Wilson Lake sediments by transmission electron microscopy. The results suggest that the high-coercivity signature identified by the authors comes from giant, needle-shaped magnetofossils in situ. This signature could be used to nondestructively detect giant magnetofossils in bulk sediment samples via magnetic measurements. According to the authors, the ability to rapidly detect these fossils in the geological record could help determine the physiology and ecology of the organisms that produce the fossils and identify periods of substantial environmental change.

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Article #20-18169: "In situ magnetic identification of giant, needle-shaped magnetofossils in Paleocene-Eocene Thermal Maximum sediments," by Courtney L. Wagner et al.

MEDIA CONTACT: Courtney L. Wagner, University of Utah, Salt Lake City, UT; tel: 315-939-0849; email: <courtney.wagner@utah.edu>; Ramon Egli, Zentralanstalt für Meteorologie und Geodynamik, Vienna, AUSTRIA; email: <ramon.egli@zamg.ac.at>; Ioan Lascu, Smithsonian National Museum of Natural History, Washington, DC; tel: 202-633-1815; email: <Lascui@si.edu>

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