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Unraveling Magnetic Anomalies: A study of Earth´s Field Asymmetries during the Laschamps Excursion

Rydh, Alexander LU (2024) In Dissertations in Geology at Lund University GEOL02 20241
Department of Geology
Abstract
Extreme geomagnetic variations such as excursions where the magnetic poles shift, and return are not fully understood. 10Be, used as a proxy for the magnetic field studies has been proposed as a compliment to paleomagnetic models, allowing adjustments. LSMOD.2 is a sediment and volcanic based magnetic model encompassing the Laschamps excursion ~41 000 years ago. LSMOD.2 is limited due to lacking data from the high latitudes and the southern hemisphere, creating uncertainties in the model. To investigate the usefulness of 10Be data, corrections must be made for climate variability, affecting the transport and deposition of 10Be, as well as filtering for solar activity, occurring as millennial and centennial variations. In this study, 10Be... (More)
Extreme geomagnetic variations such as excursions where the magnetic poles shift, and return are not fully understood. 10Be, used as a proxy for the magnetic field studies has been proposed as a compliment to paleomagnetic models, allowing adjustments. LSMOD.2 is a sediment and volcanic based magnetic model encompassing the Laschamps excursion ~41 000 years ago. LSMOD.2 is limited due to lacking data from the high latitudes and the southern hemisphere, creating uncertainties in the model. To investigate the usefulness of 10Be data, corrections must be made for climate variability, affecting the transport and deposition of 10Be, as well as filtering for solar activity, occurring as millennial and centennial variations. In this study, 10Be flux data shows good agreement with LSMOD.2 between 40.5 to 41.2 ka. After 41.2 ka the Greenland and Antarctica data diverge in 10Be production rates with LSMOD.2. Comparing 10Be data with other magnetic field reconstructions shows that LSMOD.2 has the best agreement over a period ca. 700 years. However, while LSMOD.2 does show the best agreement with 10Be data, none of the investigated magnetic field models show an overall good agreement with 10Be data or each other, thus 10Be data is limited to uses for local models e.g. northern hemisphere. (Less)
Popular Abstract (Swedish)
Har du någonsin hört talas om en supernova? En exploderande stjärna som kastar ut högenergetiska partiklar. Inte nog med det så färdas även dessa partiklar genom hela galaxen. Galaxer är stora och endast några ut av partiklarna når vår jord. Vi kan finna dessa partiklar i en iskärna och på så sätt har forskare kunnat få tag på information som behövs för att kunna studera jordens magnetfält. Med informationen har forskare tagit reda på att jordens magnetfält har förändrats genom tiden. En av dessa förändringar är polomkastningar, där magnetfältets nordpol och sydpol byter plats. Om vi inte studerar dessa förändringar skulle det innebära katastrof för mänskligheten.
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author
Rydh, Alexander LU
supervisor
organization
course
GEOL02 20241
year
type
M2 - Bachelor Degree
subject
keywords
Cosmic rays · Cosmogenic Radionuclides · Paleomagnetism · Laschamps excursion · 10Be
publication/series
Dissertations in Geology at Lund University
report number
686
language
English
id
9163247
date added to LUP
2024-06-13 16:00:35
date last changed
2024-06-13 16:00:35
@misc{9163247,
  abstract     = {{Extreme geomagnetic variations such as excursions where the magnetic poles shift, and return are not fully understood. 10Be, used as a proxy for the magnetic field studies has been proposed as a compliment to paleomagnetic models, allowing adjustments. LSMOD.2 is a sediment and volcanic based magnetic model encompassing the Laschamps excursion ~41 000 years ago. LSMOD.2 is limited due to lacking data from the high latitudes and the southern hemisphere, creating uncertainties in the model. To investigate the usefulness of 10Be data, corrections must be made for climate variability, affecting the transport and deposition of 10Be, as well as filtering for solar activity, occurring as millennial and centennial variations. In this study, 10Be flux data shows good agreement with LSMOD.2 between 40.5 to 41.2 ka. After 41.2 ka the Greenland and Antarctica data diverge in 10Be production rates with LSMOD.2. Comparing 10Be data with other magnetic field reconstructions shows that LSMOD.2 has the best agreement over a period ca. 700 years. However, while LSMOD.2 does show the best agreement with 10Be data, none of the investigated magnetic field models show an overall good agreement with 10Be data or each other, thus 10Be data is limited to uses for local models e.g. northern hemisphere.}},
  author       = {{Rydh, Alexander}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Dissertations in Geology at Lund University}},
  title        = {{Unraveling Magnetic Anomalies: A study of Earth´s Field Asymmetries during the Laschamps Excursion}},
  year         = {{2024}},
}