Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances
In the last decades, palaeomagnetic research has provided important information about the past variation of the Earth's magnetic field (EMF) from its origin to the present day. However, questions regarding the origin and evolution of the EMF as well as the frequency and spatial distribution of its variations still remain open to debate. This Special Publication provides new insights into the study of the temporal and spatial evolution of the EMF presenting new data from palaeomagnetic and rock magnetic studies of archaeological materials, sediments and lavas. The papers presented cover a wide range of topics related to archaeology, stratigraphy and climate, including new data from several parts of the world, such as Europe, Africa, Australia, New Zealand, India and the Baltic Sea. This Special Publication aims to present an overview of the most recent secular variation studies and their use to disclose fundamental properties of the EMF evolution.
A 4500 year record of palaeomagnetic secular variation and relative palaeointensity from the Tyrrhenian Sea
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Published:September 23, 2020
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CiteCitation
Pontus Lurcock, Fabio Florindo, Sergio Bonomo, Antonio Cascella, Federico Di Rita, Luciana Ferraro, Donatella Domenica Insinga, Donatella Magri, Giulia Margaritelli, Nicola Pelosi, Paola Petrosino, Mattia Vallefuoco, Claudia Cosentino, Fabrizio Lirer, 2020. "A 4500 year record of palaeomagnetic secular variation and relative palaeointensity from the Tyrrhenian Sea", Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances, E. Tema, A. Di Chiara, E. Herrero-Bervera
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Abstract
A marine sediment core from the western Mediterranean provides a new high-resolution 4500 year record of palaeomagnetic secular variation and relative palaeointensity. In 2013, the 7.1 m C5 core was recovered from the Tyrrhenian Sea as part of the NextData climate data project. The coring site, 15 km offshore from the Volturno river mouth, is well located to record combined marine and terrestrial palaeoclimatic influences, and the fine-grained, rapidly deposited sediments are effective palaeomagnetic recorders. We investigate the palaeomagnetic field direction and strength recorded in the core, which provide a valuable high-resolution record of Holocene geomagnetic variation in the area. Using rock magnetic techniques, we constrain the magnetic mineralogy of the studied sediments and confirm their suitability for palaeomagnetic analysis. Palaeomagnetic declination and inclination records were determined by stepwise alternating-field demagnetization, and relative palaeointensity estimates were obtained based on normalization to anhysterestic and isothermal remanent magnetization and to magnetic susceptibility. The age of the core is well constrained with a tephra and biostratigraphic age model, and its magnetic records are compared with relevant core and model data for the region, demonstrating that our record is compatible with previous results from the area. An automated curve matching approach is applied to assess the compatibility of our data with the existing secular variation path for the Mediterranean area.
- alternating field demagnetization
- anhysteretic remanent magnetization
- Cenozoic
- cores
- demagnetization
- high-resolution methods
- Holocene
- isothermal remanent magnetization
- magnetic declination
- magnetic field
- magnetic inclination
- magnetic intensity
- magnetic minerals
- magnetic properties
- magnetic susceptibility
- magnetization
- marine environment
- marine sediments
- Mediterranean Sea
- paleoclimatology
- paleomagnetism
- Quaternary
- remanent magnetization
- sampling
- secular variations
- sediments
- temperature
- terrestrial environment
- Tyrrhenian Sea
- West Mediterranean
- Volturno River