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Multi-proxy identification of the Laschamp geomagnetic field excursion in Lake Pupuke, New Zealand

Nilsson, Andreas LU ; Muscheler, Raimund LU ; Snowball, Ian LU ; Aldahan, Ala; Possnert, Goran; Augustinus, Paul; Atkin, Daniel and Stephens, Tom (2011) In Earth and Planetary Science Letters 311(1-2). p.155-164
Abstract
We present palaeomagnetic and cosmogenic radionuclide records of the Laschamp geomagnetic excursion in Lake Pupuke, a maar lake in Auckland, New Zealand. Laschamp was identified by a combination of relative palaeointensity, (10)Be and (14)C data from the lake sediments and represents the first such record from the Southern Hemisphere. Despite the high organic carbon content, which causes relatively weak natural remanent magnetisations, the geomagnetic intensity minimum associated with the Laschamp excursion is identifiable as a relative palaeointensity minimum that is synchronous with (i) a peak in (10)Be concentration and (ii) an anomaly in Delta(14)C. The Lake Pupuke time scale, provided by (14)C data calibrated with INTCAL09, places the... (More)
We present palaeomagnetic and cosmogenic radionuclide records of the Laschamp geomagnetic excursion in Lake Pupuke, a maar lake in Auckland, New Zealand. Laschamp was identified by a combination of relative palaeointensity, (10)Be and (14)C data from the lake sediments and represents the first such record from the Southern Hemisphere. Despite the high organic carbon content, which causes relatively weak natural remanent magnetisations, the geomagnetic intensity minimum associated with the Laschamp excursion is identifiable as a relative palaeointensity minimum that is synchronous with (i) a peak in (10)Be concentration and (ii) an anomaly in Delta(14)C. The Lake Pupuke time scale, provided by (14)C data calibrated with INTCAL09, places the (10)Be maximum at the same time as a (10)Be maximum in Greenland ice cores when secured to the GICC05 time scale. The central age of the Laschamp geomagnetic excursion in Lake Pupuke as defined by the (10)Be prediction peak is c. 41 kyr, which confirms its global application as a palaeomagnetic isochron. Anomalous palaeomagnetic directional data at c. 32 kyr in the Lake Pupuke sediments may represent the Mono Lake geomagnetic excursion, but tephra layers caused by frequent eruptions in the Auckland volcanic field during this excursion probably disrupted the palaeointensity signal. The study highlights the value of combining traditional palaeomagnetic methods with measurements of cosmogenic radionuclides in the quest for accurate and precise geochronologies during MIS3, a time of rapid global climate change. (C) 2011 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Laschamp excursion, geomagnetic field intensity, cosmogenic, radionuclides, palaeomagnetism, lake sediments, Lake Pupuke
in
Earth and Planetary Science Letters
volume
311
issue
1-2
pages
155 - 164
publisher
Elsevier
external identifiers
  • wos:000298270100014
  • scopus:81155139655
ISSN
1385-013X
DOI
10.1016/j.epsl.2011.08.050
language
English
LU publication?
yes
id
c59928b7-e550-4784-acfd-f0d93343f78b (old id 2333509)
date added to LUP
2012-02-06 13:25:49
date last changed
2017-07-30 03:19:09
@article{c59928b7-e550-4784-acfd-f0d93343f78b,
  abstract     = {We present palaeomagnetic and cosmogenic radionuclide records of the Laschamp geomagnetic excursion in Lake Pupuke, a maar lake in Auckland, New Zealand. Laschamp was identified by a combination of relative palaeointensity, (10)Be and (14)C data from the lake sediments and represents the first such record from the Southern Hemisphere. Despite the high organic carbon content, which causes relatively weak natural remanent magnetisations, the geomagnetic intensity minimum associated with the Laschamp excursion is identifiable as a relative palaeointensity minimum that is synchronous with (i) a peak in (10)Be concentration and (ii) an anomaly in Delta(14)C. The Lake Pupuke time scale, provided by (14)C data calibrated with INTCAL09, places the (10)Be maximum at the same time as a (10)Be maximum in Greenland ice cores when secured to the GICC05 time scale. The central age of the Laschamp geomagnetic excursion in Lake Pupuke as defined by the (10)Be prediction peak is c. 41 kyr, which confirms its global application as a palaeomagnetic isochron. Anomalous palaeomagnetic directional data at c. 32 kyr in the Lake Pupuke sediments may represent the Mono Lake geomagnetic excursion, but tephra layers caused by frequent eruptions in the Auckland volcanic field during this excursion probably disrupted the palaeointensity signal. The study highlights the value of combining traditional palaeomagnetic methods with measurements of cosmogenic radionuclides in the quest for accurate and precise geochronologies during MIS3, a time of rapid global climate change. (C) 2011 Elsevier B.V. All rights reserved.},
  author       = {Nilsson, Andreas and Muscheler, Raimund and Snowball, Ian and Aldahan, Ala and Possnert, Goran and Augustinus, Paul and Atkin, Daniel and Stephens, Tom},
  issn         = {1385-013X},
  keyword      = {Laschamp excursion,geomagnetic field intensity,cosmogenic,radionuclides,palaeomagnetism,lake sediments,Lake Pupuke},
  language     = {eng},
  number       = {1-2},
  pages        = {155--164},
  publisher    = {Elsevier},
  series       = {Earth and Planetary Science Letters},
  title        = {Multi-proxy identification of the Laschamp geomagnetic field excursion in Lake Pupuke, New Zealand},
  url          = {http://dx.doi.org/10.1016/j.epsl.2011.08.050},
  volume       = {311},
  year         = {2011},
}