loading page

Deep-sea rare-earth mineral resources formed in the early Eocene Hothouse ocean: Insights from deep learning-based microfossil observations
  • +4
  • Kazuhide Mimura,
  • Takahiro Kitazawa,
  • Kentaro Nakamura,
  • Kazutaka Yasukawa,
  • Yusuke Kuwahara,
  • Junichiro Ohta,
  • Yasuhiro Kato
Kazuhide Mimura
National Institute of Advanced Industrial Science and Technology

Corresponding Author:[email protected]

Author Profile
Takahiro Kitazawa
University of Tokyo
Author Profile
Kentaro Nakamura
University of Tokyo
Author Profile
Kazutaka Yasukawa
University of Tokyo
Author Profile
Yusuke Kuwahara
University of Tokyo
Author Profile
Junichiro Ohta
University of Tokyo
Author Profile
Yasuhiro Kato
University of Tokyo
Author Profile

Abstract

Deep-sea mud enriched in rare-earth elements (REEs), termed REE-rich mud, is a promising seafloor mineral resource. A decade of surveys has revealed that the mud with the highest REE concentration occurs in the pelagic realm of the western North Pacific Ocean, with two layers of elevated REE concentration. Previous analyses of sediments have revealed multiple periods of significant REE enrichment, with the first (youngest) REE enrichment triggered by global cooling during the Eocene–Oligocene climate transition. However, the depositional mechanism of older REE peaks remains unclear. Fish debris is the major host of REE in deep-sea sediments. In this study, the microfossils of fish teeth and denticles, called ichthyoliths, were observed to constrain the depositional ages of REE-enriched layers with unknown genesis. Empowered by deep learning, more than 40,000 ichthyoliths were observed, and the second (older) REE enrichment was revealed to have occurred in the early Eocene, when the Earth’s climate was exceedingly warm. The warm ocean may have enhanced the efficiency of trophic transfer, leading to an increased supply of fish debris and thus REE, to the seafloor. Therefore, the Paleogene Hothouse might have been advantageous for producing valuable seafloor mineral resources.
05 Jun 2024Submitted to ESS Open Archive
10 Jun 2024Published in ESS Open Archive