Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Preliminary Characterization of Submarine Basalt Magnetic Mineralogy Using Amplitude-Dependence of Magnetic Susceptibility

Yang, H. ; Tikoo, S. M. ; Carvallo, C. ; Bilardello, D. ; Solheid, P. ; Gaastra, K. M. ; Sager, W. W. ; Thoram, S. ; Hoernle, K. and Höfig, T. W. , et al. (2024) In Geochemistry, Geophysics, Geosystems 25(2).
Abstract

The past ∼200 million years of Earth's geomagnetic field behavior have been recorded within oceanic basalts, many of which are only accessible via scientific ocean drilling. Obtaining the best possible paleomagnetic measurements from such valuable samples requires an a priori understanding of their magnetic mineralogies when choosing the most appropriate protocol for stepwise demagnetization experiments (either alternating field or thermal). Here, we present a quick, and non-destructive method that utilizes the amplitude-dependence of magnetic susceptibility to screen submarine basalts prior to choosing a demagnetization protocol, whenever conducting a pilot study or other detailed rock-magnetic characterization is not possible. We... (More)

The past ∼200 million years of Earth's geomagnetic field behavior have been recorded within oceanic basalts, many of which are only accessible via scientific ocean drilling. Obtaining the best possible paleomagnetic measurements from such valuable samples requires an a priori understanding of their magnetic mineralogies when choosing the most appropriate protocol for stepwise demagnetization experiments (either alternating field or thermal). Here, we present a quick, and non-destructive method that utilizes the amplitude-dependence of magnetic susceptibility to screen submarine basalts prior to choosing a demagnetization protocol, whenever conducting a pilot study or other detailed rock-magnetic characterization is not possible. We demonstrate this method using samples acquired during International Ocean Discovery Program Expedition 391. Our approach is rooted in the observation that amplitude-dependent magnetic susceptibility is observed in basalt samples whose dominant magnetic carrier is multidomain titanomagnetite (∼TM60–65, (Ti0.60–0.65Fe0.35–0.40)Fe2O4). Samples with low Ti contents within titanomagnetite or samples that have experienced a high degree of oxidative weathering do not display appreciable amplitude dependence. Due to their low Curie temperatures, basalts that possess amplitude-dependence should ideally be demagnetized either using alternating fields or via finely-spaced thermal demagnetization heating steps below 300°C. Our screening method can enhance the success rate of paleomagnetic studies of oceanic basalt samples.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Geochemistry, Geophysics, Geosystems
volume
25
issue
2
article number
e2023GC011222
publisher
American Geophysical Union (AGU)
external identifiers
  • scopus:85183908538
ISSN
1525-2027
DOI
10.1029/2023GC011222
language
English
LU publication?
yes
id
48a83050-fb32-4fb5-a7e4-211cff0165f2
date added to LUP
2024-03-08 13:42:48
date last changed
2024-03-08 13:43:35
@article{48a83050-fb32-4fb5-a7e4-211cff0165f2,
  abstract     = {{<p>The past ∼200 million years of Earth's geomagnetic field behavior have been recorded within oceanic basalts, many of which are only accessible via scientific ocean drilling. Obtaining the best possible paleomagnetic measurements from such valuable samples requires an a priori understanding of their magnetic mineralogies when choosing the most appropriate protocol for stepwise demagnetization experiments (either alternating field or thermal). Here, we present a quick, and non-destructive method that utilizes the amplitude-dependence of magnetic susceptibility to screen submarine basalts prior to choosing a demagnetization protocol, whenever conducting a pilot study or other detailed rock-magnetic characterization is not possible. We demonstrate this method using samples acquired during International Ocean Discovery Program Expedition 391. Our approach is rooted in the observation that amplitude-dependent magnetic susceptibility is observed in basalt samples whose dominant magnetic carrier is multidomain titanomagnetite (∼TM<sub>60–65</sub>, (Ti<sub>0.60–0.65</sub>Fe<sub>0.35–0.40</sub>)Fe<sub>2</sub>O<sub>4</sub>). Samples with low Ti contents within titanomagnetite or samples that have experienced a high degree of oxidative weathering do not display appreciable amplitude dependence. Due to their low Curie temperatures, basalts that possess amplitude-dependence should ideally be demagnetized either using alternating fields or via finely-spaced thermal demagnetization heating steps below 300°C. Our screening method can enhance the success rate of paleomagnetic studies of oceanic basalt samples.</p>}},
  author       = {{Yang, H. and Tikoo, S. M. and Carvallo, C. and Bilardello, D. and Solheid, P. and Gaastra, K. M. and Sager, W. W. and Thoram, S. and Hoernle, K. and Höfig, T. W. and Avery, A. and Del Gaudio, A. V. and Huang, Y. and Bhutani, R. and Buchs, D. M. and Class, C. and Dai, Y. and Dalla Valle, G. and Fielding, S. and Han, S. and Heaton, D. E. and Homrighausen, S. and Kubota, Y. and Li, C. F. and Nelson, W. R. and Petrou, E. and Potter, K. E. and Pujatti, S. and Scholpp, J. and Shervais, J. W. and Tshiningayamwe, M. and Wang, X. J. and Widdowson, M.}},
  issn         = {{1525-2027}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{American Geophysical Union (AGU)}},
  series       = {{Geochemistry, Geophysics, Geosystems}},
  title        = {{Preliminary Characterization of Submarine Basalt Magnetic Mineralogy Using Amplitude-Dependence of Magnetic Susceptibility}},
  url          = {{http://dx.doi.org/10.1029/2023GC011222}},
  doi          = {{10.1029/2023GC011222}},
  volume       = {{25}},
  year         = {{2024}},
}