Nanogoethite as a Potential Indicator of Remagnetization in Red Beds

Wentao Huang*, Michael J. Jackson, Mark J. Dekkers, Peat Solheid, Bo Zhang, Zhaojie Guo, Lin Ding

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Red beds are well-known for recording stable natural remanent magnetization (NRM). However, discriminating primary NRM from secondary remanence in red beds is difficult. The Paleogene Nangqian red beds in eastern Tibetan Plateau variably record an overprint related to nearby magmatism and thus provide a great opportunity to characterize remagnetization in red beds. Through comprehensive rock magnetic, Mössbauer spectroscopic, and petrographic analyses, we find that remagnetization was controlled by temperature. Remagnetized red beds contain abundant authigenic hematite and goethite, with some larger grains unblocking at the Néel temperatures and the remainder (nanoparticles) unblocking at lower temperatures. In contrast, red beds retaining primary NRM are characterized by dominance of detrital hematite and magnetite, presence of fine-grained authigenic hematite, and absence of authigenic goethite and magnetite. High temperature behaviors of NRM/susceptibility are indicative of remagnetization, but the presence of goethite appears to be a more sensitive criterion for diagnosing remagnetization in red beds.

Original languageEnglish
Pages (from-to)12841-12850
Number of pages10
JournalGeophysical Research Letters
Volume46
Issue number22
DOIs
Publication statusPublished - 28 Nov 2019

Keywords

  • goethite
  • hematite
  • magnetite
  • red beds
  • remagnetization

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