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| Open AccessEarly Cambrian renewal of the geodynamo and the origin of inner core structure
New single crystal paleointensity data show that the geomagnetic field was renewed in the early Cambrian after near collapse in the Ediacaran Period. This implies that the innermost/outermost structure of the inner core formed 450 million yrs. ago.
- Tinghong Zhou
- , John A. Tarduno
- & Frank Padgett III
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| Open AccessStalagmite paleomagnetic record of a quiet mid-to-late Holocene field activity in central South America
The South Atlantic Anomaly has the lowest intensity of the geomagnetic field. A stalagmite, from Brazil shows through its magnetic remanence that in mid-to-late Holocene this anomaly, was not being expressed or recurrent at surface in millennial scale.
- Plinio Jaqueto
- , Ricardo I. F. Trindade
- & R. Lawrence Edwards
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| Open AccessLong-term exposure to a hypomagnetic field attenuates adult hippocampal neurogenesis and cognition
Exposure to a hypomagnetic field (HMF) influences the cognitive processes of various animals, from insects to human beings. The authors show that in mice exposed to HMF, adult hippocampal neurogenesis and hippocampusdependent learning are impaired and could be rescued by restoring ROS levels.
- Bingfang Zhang
- , Lei Wang
- & Yongxin Pan
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| Open AccessQuantitative estimates of average geomagnetic axial dipole dominance in deep geological time
This study describes how the geomagnetic axial dipole dominance of Earth’s magnetic field remained stable through large parts of the geological time. Since other characteristics of the geomagnetic field have changed substantially on the same timescales, this new observation provides a challenge for future core modeling studies.
- Andrew J. Biggin
- , Richard K. Bono
- & Pavel V. Doubrovine
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| Open AccessRapid geomagnetic changes inferred from Earth observations and numerical simulations
The authors here use numerical simulations combined with a time-dependent model of Earth’s magnetic field spanning the last 100 kyrs. They identify field directional changes to be 10 times faster than previously thought.
- Christopher J. Davies
- & Catherine G. Constable
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| Open AccessElectrical conductivity and magnetic dynamos in magma oceans of Super-Earths
With the discovery of large rocky exoplanets called Super-Earths, questions have arisen regarding the properties of their interiors and their ability to produce a magnetic field. Here, the authors show that under high pressure, molten silicates are semi-metallic and that magma oceans would host a dynamo process.
- François Soubiran
- & Burkhard Militzer
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| Open AccessMulti-scale magnetic mapping of serpentinite carbonation
Peridotite carbonation plays an important role in the carbon cycle. Here, the authors present a geophysical characterization of serpentinite carbonation from km to mm scale and confirm that the abundance of magnetic minerals provides a strong correlation with the overall carbonation reaction process.
- Masako Tominaga
- , Andreas Beinlich
- & Yumiko Harigane
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| Open AccessVolcanism in slab tear faults is larger than in island-arcs and back-arcs
The volcanism of subduction settings concentrates in island-arcs and back-arc basins. Here, the authors show that the lithospheric tear faults bounding roll-backing slabs may focus huge volcanism with a volume of the erupted products exceeding that of the island-arcs edifices and back-arcs spreading centres.
- Luca Cocchi
- , Salvatore Passaro
- & Guido Ventura
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| Open AccessGeomagnetic spikes on the core-mantle boundary
Rapid and spatially localized geomagnetic field variations around 1000 BC are hard to reconcile with expected field behaviour arising from the core dynamo. Here, the authors show that the intensity spike is consistent with an intense flux patch on the core-mantle boundary (8–22°) located under Saudi Arabia.
- Christopher Davies
- & Catherine Constable
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| Open AccessVisualized effect of oxidation on magnetic recording fidelity in pseudo-single-domain magnetite particles
Magnetite provides a valuable record of the Earth's geomagnetic history. Here, Almeida et al. combine electron microscopy and energy-loss spectroscopy to study the effects of in situoxidation on the magnetization fidelity and crystalline phase of pseudo-single domain magnetite grains.
- Trevor P. Almeida
- , Takeshi Kasama
- & Rafal E. Dunin-Borkowski
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Magnetic force microscopy reveals meta-stable magnetic domain states that prevent reliable absolute palaeointensity experiments
Obtaining reliable estimates of the absolute palaeointensity of the Earth’s magnetic field is difficult and many methods induce alteration. de Groot et al.present a means to see and explain changes in magnetization in unreliable samples, explaining why some samples systematically fail paleointensity experiments.
- Lennart V. de Groot
- , Karl Fabian
- & Mark J. Dekkers
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| Open AccessAn electromagnetic field disrupts negative geotaxis in Drosophila via a CRY-dependent pathway
The earth’s electromagnetic field has a modest effect on the behaviour of Drosophila melanogaster. Here, Fedele et al. use an assessment of climbing behaviour to describe how the blue-light circadian photoreceptor cryptochrome mediates a negative movement response to gravity in flies.
- Giorgio Fedele
- , Edward W. Green
- & Charalambos P. Kyriacou
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| Open AccessRapid regional perturbations to the recent global geomagnetic decay revealed by a new Hawaiian record
The Earth’s geomagnetic field has weakened in recent centuries, leading to calls for historic reconstructions; however, records are sparse and unevenly distributed. de Groot et al.provide a new, high-quality record from Hawaiian lavas, revealing crucial insights into past geomagnetic field fluctuations.
- L. V. de Groot
- , A. J. Biggin
- & E. Herrero-Bervera