Publication Date:
2017-04-04
Description:
The Auckland Volcanic Field contains several maars that formed after the last interglacial
and subsequently filled with sediment. Two of these maars, Pukaki and Onepoto, were
recently cored as part of the Auckland Maar Lakes Project. The tephra stratigraphy of the
cores indicates that sediment accumulated relatively slowly in both maars until the
Holocene when ocean waters breached the craters and they filled up quite rapidly. Using u-channels, we collected 23 m of pre-Holocene lacustrine sediment from the Pukaki 1-01 core and 15 m from the Onepoto core. Paleomagnetic measurements were performed on
these at the University of California, Davis. Environmental magnetic records from both cores provide insights in particular about the eruptive history of the Auckland Volcanic Field. The lack of a tephrostratigraphic control in the lower portion of the cores, and the lack of similar trends in the magnetic parameters, prevented a complete core correlation.
The main finding is that local basaltic tephra layers visible in the cores show up as spikes in the concentration dependent magnetic parameters, suggesting that other spikes represent tephra layers that are not as easily discerned.
Description:
In press
Description:
2.2. Laboratorio di paleomagnetismo
Description:
JCR Journal
Description:
open
Keywords:
Environmental magnetism
;
Pukaki
;
Onepoto
;
Auckland Volcanic Field
;
maars
;
ash deposits
;
04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
;
04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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