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In situ magnetic identification of giant, needle-shaped magnetofossils in Paleocene–Eocene Thermal Maximum sediments
- Source :
- Proc Natl Acad Sci U S A
- Publication Year :
- 2021
- Publisher :
- National Academy of Sciences, 2021.
-
Abstract
- Near-shore marine sediments deposited during the Paleocene-Eocene Thermal Maximum at Wilson Lake, NJ, contain abundant conventional and giant magnetofossils. We find that giant, needle-shaped magnetofossils from Wilson Lake produce distinct magnetic signatures in low-noise, high-resolution first-order reversal curve (FORC) measurements. These magnetic measurements on bulk sediment samples identify the presence of giant, needle-shaped magnetofossils. Our results are supported by micromagnetic simulations of giant needle morphologies measured from transmission electron micrographs of magnetic extracts from Wilson Lake sediments. These simulations underscore the single-domain characteristics and the large magnetic coercivity associated with the extreme crystal elongation of giant needles. Giant magnetofossils have so far only been identified in sediments deposited during global hyperthermal events and therefore may serve as magnetic biomarkers of environmental disturbances. Our results show that FORC measurements are a nondestructive method for identifying giant magnetofossil assemblages in bulk sediments, which will help test their ecology and significance with respect to environmental change.
- Subjects :
- In situ
Magnetic measurements
Aquatic Organisms
Geologic Sediments
Multidisciplinary
Magnetotactic bacteria
Fossils
Magnetic Phenomena
Mineralogy
Sediment
Coercivity
Ferrosoferric Oxide
Physical Phenomena
Magnetics
Transmission electron micrograph
Carbon isotope excursion
Physical Sciences
Humans
Magnetosomes
Geology
Magnetofossil
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Proc Natl Acad Sci U S A
- Accession number :
- edsair.doi.dedup.....346d29f596d44499b077f3aab6e79d9c