Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Constraining the eruption history of Rangitoto volcano, New Zealand, using palaeomagnetic data

Allington, Megan L. LU orcid ; Nilsson, Andreas LU ; Hill, Mimi J. ; Suttie, Neil LU orcid ; Daniil, Dimitra ; Hjorth, Ingeborg ; Aulin, Linda ; Augustinus, Paul C. and Shane, Phil (2023) In Quaternary Geochronology 78.
Abstract

New Zealand's largest city, Auckland, is situated within the basaltic Auckland Volcanic Field (AVF). Therefore, understanding the eruption history of the local volcanoes in the field is of great importance in order to assess future hazards that they may pose. Rangitoto is the youngest and largest volcano in the AVF, although the timing of the first eruption and the duration of the volcanic activity are still uncertain. Here, we use palaeomagnetic methods to provide additional constraints to the duration of the main shield-building phase of Rangitoto, previously estimated to have lasted either less than 100 years or approximately 1000 years. Lava flow samples from an ∼140 m length vertically oriented drill core produced 203... (More)

New Zealand's largest city, Auckland, is situated within the basaltic Auckland Volcanic Field (AVF). Therefore, understanding the eruption history of the local volcanoes in the field is of great importance in order to assess future hazards that they may pose. Rangitoto is the youngest and largest volcano in the AVF, although the timing of the first eruption and the duration of the volcanic activity are still uncertain. Here, we use palaeomagnetic methods to provide additional constraints to the duration of the main shield-building phase of Rangitoto, previously estimated to have lasted either less than 100 years or approximately 1000 years. Lava flow samples from an ∼140 m length vertically oriented drill core produced 203 palaeoinclinations and 74 palaeointensity estimates. Our results show significant variation in both inclination (up to 30°) and intensities (which fall between 25 and 60 μT; present day field values for Auckland are ∼55 μT). Potential non-geomagnetic explanations for these variations, including thermochemical processes and rheological deformation are discussed. A statistical model was created to determine the minimum duration for the construction of Rangitoto that is compatible with the variations in the palaeomagnetic data, using prior information about the rate of change of the geomagnetic field. We conclude that the palaeomagnetic data are incompatible with the previously suggested short duration (under 100 years) of the shield-building phase and suggest instead a range of 150–450 years, when also accounting for the available radiocarbon ages. Given these results, this has implications for the timing, and thus impact of possible future eruptions in the AVF.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Magnetic inclination, Palaeointensity, Southern hemisphere, Volcanology
in
Quaternary Geochronology
volume
78
article number
101459
publisher
Elsevier
external identifiers
  • scopus:85166349018
ISSN
1871-1014
DOI
10.1016/j.quageo.2023.101459
language
English
LU publication?
yes
id
d77ef601-43fb-456e-8be2-665b982d20a5
date added to LUP
2023-10-27 16:48:40
date last changed
2023-10-27 16:48:40
@article{d77ef601-43fb-456e-8be2-665b982d20a5,
  abstract     = {{<p>New Zealand's largest city, Auckland, is situated within the basaltic Auckland Volcanic Field (AVF). Therefore, understanding the eruption history of the local volcanoes in the field is of great importance in order to assess future hazards that they may pose. Rangitoto is the youngest and largest volcano in the AVF, although the timing of the first eruption and the duration of the volcanic activity are still uncertain. Here, we use palaeomagnetic methods to provide additional constraints to the duration of the main shield-building phase of Rangitoto, previously estimated to have lasted either less than 100 years or approximately 1000 years. Lava flow samples from an ∼140 m length vertically oriented drill core produced 203 palaeoinclinations and 74 palaeointensity estimates. Our results show significant variation in both inclination (up to 30°) and intensities (which fall between 25 and 60 μT; present day field values for Auckland are ∼55 μT). Potential non-geomagnetic explanations for these variations, including thermochemical processes and rheological deformation are discussed. A statistical model was created to determine the minimum duration for the construction of Rangitoto that is compatible with the variations in the palaeomagnetic data, using prior information about the rate of change of the geomagnetic field. We conclude that the palaeomagnetic data are incompatible with the previously suggested short duration (under 100 years) of the shield-building phase and suggest instead a range of 150–450 years, when also accounting for the available radiocarbon ages. Given these results, this has implications for the timing, and thus impact of possible future eruptions in the AVF.</p>}},
  author       = {{Allington, Megan L. and Nilsson, Andreas and Hill, Mimi J. and Suttie, Neil and Daniil, Dimitra and Hjorth, Ingeborg and Aulin, Linda and Augustinus, Paul C. and Shane, Phil}},
  issn         = {{1871-1014}},
  keywords     = {{Magnetic inclination; Palaeointensity; Southern hemisphere; Volcanology}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Quaternary Geochronology}},
  title        = {{Constraining the eruption history of Rangitoto volcano, New Zealand, using palaeomagnetic data}},
  url          = {{http://dx.doi.org/10.1016/j.quageo.2023.101459}},
  doi          = {{10.1016/j.quageo.2023.101459}},
  volume       = {{78}},
  year         = {{2023}},
}