Micromagnetic Tomography for Paleomagnetism and Rock-Magnetism

Area of Science:

• Geophysics
• Paleomagnetism
• Rock Magnetism

Background:

• Earth's past geomagnetic field is studied using magnetic signals in geological materials like volcanic rocks.
• Bulk rock samples contain diverse magnetic grains, some unreliable, potentially obscuring crucial paleomagnetic data.
• Existing methods struggle with samples containing a small fraction of poorly behaved magnetic grains.

Purpose of the Study:

• To establish and validate the Micromagnetic Tomography (MMT) technique for analyzing individual magnetic grains.
• To demonstrate MMT's applicability to both synthetic and natural geological samples.
• To enable more accurate paleomagnetic and rock-magnetic research by analyzing individual grain magnetizations.

Main Methods:

• Combining X-ray computed tomography with magnetic surface scanning measurements.
• Developing the Micromagnetic Tomography (MMT) technique for non-destructive analysis.
• Applying MMT to synthetic samples for controlled validation and natural volcanic samples for real-world application.

Main Results:

• Reliable magnetic directions were obtained from selected subsets of grains in a synthetic sample.
• Individual grain-level rock-magnetic information was successfully acquired from a volcanic sample.
• Demonstrated MMT's capability to analyze magnetization at the individual grain level.

Conclusions:

• Micromagnetic Tomography (MMT) offers a novel approach to paleomagnetic and rock-magnetic research.
• MMT allows for systematic analysis of how geological materials record geomagnetic field information.
• The technique can potentially recover paleomagnetic data from complex samples currently inaccessible to traditional methods.