Authors
Karen Okada, Shin Toyoda, Masashi Takada
Published in
International journal of radiation biology. Pages 1-6. Sep 08, 2025. Epub Sep 08, 2025.
Abstract
The number of oxygen vacancies in quartz measured by electron spin resonance (ESR) as the intensity of the E1' center has been used to investigate the provenance of the sediments and has been found to be a good proxy in discussing the direction and intensity of the wind system in the past. While its temporal variations have been examined using marine sediments. The present study aimed to show that terrestrial sediments are also useful for such studies on climate change when it is continuous.
Samples from a continuous tephric loess sequence were examined in the present study. Samples were collected from Kamiyoshida outcrop in Rokunohe Town, Aomori Prefecture, with 5 cm intervals from 110 cm to 420 cm, and a total of 61 samples were analyzed. XRD (X-ray diffraction) analysis was employed to correct the content of quartz in the chemically processed samples.
Three peaks of the number of oxygen vacancies were observed (15-20, 40-50, and 70-75 ka) for the grain size fractions <2-20, and 20-50 µm. These three peeks look corresponding to the peaks in marine sediments observed in a previous work. During these periods, the amount of eolian dust supplied from the Chinese continent may have been larger, resulting in higher oxygen vacancy values in quartz in both sediments of Sea of Japan and of tephric loess sequence on land. The present results indicate that land sedimentary sequence would be as useful as marine sediments for studying past wind systems.
PMID:
40920968
Bibliographic data and abstract were imported from PubMed on 09 Sep 2025.
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