To evaluate the effect of undersaturation of magnetic hysteresis loops measured in moderate (<2 T) fields in magnetically hard minerals such as goethite or hematite, we measured room temperature hysteresis loops in a 7 T field and DC backfield demagnetization curves in fields up to 3 T using an MPMS 3 instrument. Sediments from different regions of the East European platform, mostly of Carboniferous age were used for this study. Similar experiments were also carried out for a small collection of archaeological ceramics (bricks) apparently containing a High Coercivity Low unblocking Temperature (HCLT) magnetic phase (ε-Fe2O3?). Hysteresis measurements were complemented by thermomagnetic analysis at low and high temperatures, microscopic observations, and X-ray diffraction studies. High-field magnetic hysteresis loops alone appear insufficient to definitively discriminate goethite from hematite, though there is, expectedly, a tendency that increasing goethite content leads to magnetic hardening, with coercive force reaching 1 T and coercivity of remanence 1.7 T. At the same time, ε-Fe2O3 can seemingly be distinguished from either hematite or goethite due to its high saturation magnetization. However, combining hysteresis measurements with low- and high-temperature thermomagnetic analysis provides a much better insight into the magnetic mineralogy of samples. Still, acquiring the reference data on well characterized hematite, goethite, and ε-Fe2O3 samples is highly desirable.

Original languageEnglish
Title of host publicationProblems of Geocosmos–2018
Subtitle of host publicationProceedings of the XII International Conference and School
EditorsTatiana Yanovskaya, Andrei Kosterov, Nikita Bobrov, Andrey Divin, Alexander Saraev, Nadezhda Zolotova
Place of PublicationCham
PublisherSpringer Nature
Number of pages16
ISBN (Electronic)978-3-030-21788-4
ISBN (Print)978-3-030-21787-7
StatePublished - 2020

Publication series

NameSpringer Proceedings in Earth and Environmental Sciences
ISSN (Print)2524-342X
ISSN (Electronic)2524-3438

    Research areas

  • Day-Dunlop plot, Goethite, HCLT phase, Hematite, Magnetic hysteresis

    Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Geophysics
  • Oceanography
  • Environmental Science (miscellaneous)

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