Climate Control of Iodine Isotopic Composition Evidenced by Argentine Entisols Records

Autor: Yukun Fan, Peng Cheng, Agustín Negri, Jianghu Lan, Xingxing Liu, Weijian Zhou, Qi Liu, Xiaolin Hou
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Geophysical Research Letters, Vol 51, Iss 4, Pp n/a-n/a (2024)
Druh dokumentu: article
ISSN: 1944-8007
0094-8276
DOI: 10.1029/2023GL107811
Popis: Abstract The long half‐life of 129I makes it useful for dating marine sediments aged 2–90 Ma. However, the lack of initial value dating hinders its application for dating terrestrial sediments. A large scatter of 129I/127I in prenuclear terrestrial samples has been reported; however, the key influencing factors remain unclear. This study presented iodine isotope data from three Argentine Entisol profiles and developed an iodine‐source model to determine the influence of the source on iodine isotopic composition. The temporal patterns demonstrated clear climate modulations in natural terrestrial iodine isotopes over the last ∼15 Kyr. The model identified rock weathering as a major source of iodine in continental sediments. Higher 129I/127I ratios at mid‐high latitudes arise from weak geomagnetic shielding of cosmic rays and thus a high production rate, implying limited meridional diffusion of atmospheric iodine. These findings reveal that environmental factors are significant for constraining the initial value of terrestrial 129I.
Databáze: Directory of Open Access Journals
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