DOI: 10.1016/j.epsl.2021.117119
论文题名: A tephra-based approach to calibrating relative geomagnetic paleointensity stacks to absolute values
作者: Mochizuki N. ; Fujii S. ; Hasegawa T. ; Yamamoto Y. ; Hatakeyama T. ; Yamashita D. ; Okada M. ; Shibuya H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 572 语种: 英语
中文关键词: absolute paleointensity
; calibration
; oxygen isotope stratigraphy
; relative paleointensity
; tephra
; welded tuff
英文关键词: Geomagnetism
; Isotopes
; Oxygen
; Stratigraphy
; Welding
; Absolute paleointensity
; Absolute values
; Axial dipole
; Geomagnetics
; Linear relationships
; Oxygen isotope stratigraphy
; Paleo-intensities
; Relative paleointensity
; Tephrum
; Welded tuff
; Calibration
英文摘要: Relative paleointensity (RPI) stacks provide a relative, global paleointensity variation, which reflects variations in the geocentric axial dipole moment. Previous calibrations of an RPI stack rely on adjusting a mean RPI to a mean of virtual axial dipole moments (VADMs), which are selected from absolute paleointensity (API) databases. To achieve more quantitative calibration of an RPI stack into absolute values, we propose a novel approach that compares (1) tephra-derived APIs and (2) the same tephras' horizons, in the oxygen isotope stratigraphy, tied RPIs (hereafter termed the “TA-TOR” approach). For the TA-TOR approach, APIs were newly determined for welded tuffs of 15 pyroclastic flow deposits in Japan. Eight of the 15 new APIs and 2 previously reported APIs have tephra horizons in the oxygen isotope stratigraphy. Based on the 10 data of the TA-TOR approach, combined with 4 data of the transitional field, VADMs calculated from the APIs (VADMAPI) were compared with isochronous RPIs from two RPI stacks, PISO-1500 and Sint-2000. The 14 data points in RPI vs. VADMAPI diagrams show a linear relationship with correlation coefficients of 0.83–0.89. Using the observed linear relationships, the two RPI stacks were reliably calibrated to VADM values (VADMRPI) for the period since 1.1 Ma. Compared with the VADMs calibrated by the previous studies, the present calibration provides a 12–13% smaller median/mean and a larger dispersion as represented by a 15–53% larger standard deviation for the two RPI stacks. The similarities between the cumulative distributions of VADMRPI from the two stacks and those of VADMs selected from the API database indicate the reliability of the present calibration. These results show that the present calibration, which relies on the TA-TOR approach, accurately converts a RPI stack into VADMRPI values and will contribute to studies on time variations in the geocentric axial dipole moment, sedimentary RPI, and cosmogenic radionuclides. Variations in VADMRPI for the past 1.1 Myr, obtained from PISO-1500 and Sint-2000 via the present calibration, can be used as standard geocentric axial dipole variations for this period. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165604
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Environmental Sciences, Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan; Department of Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan; Department of Earth Sciences, College of Science, Ibaraki University, Mito, 310-8512, Japan; Center for Advanced Marine Core Research, Kochi University, Kochi, 783-8502, Japan; Institute of Frontier Science and Technology, Okayama University of Science, Okayama, 700-0005, Japan; Satsumasendai City Office, Satsumasendai, 896-1392, Japan; Research Center for Knowledge Science in Cultural Heritage, Doshisya University, Kyotanabe, 610-0394, Japan
Recommended Citation:
Mochizuki N.,Fujii S.,Hasegawa T.,et al. A tephra-based approach to calibrating relative geomagnetic paleointensity stacks to absolute values[J]. Earth and Planetary Science Letters,2021-01-01,572