Paleomagnetism and rock-magnetism by Micro-Magnetic Tomography

Descrizione del progetto

La tomografia all’avanguardia fornisce istantanee più chiare del mutevole magnetismo terrestre

Il campo magnetico terrestre forma una bolla protettiva che protegge la terra dalle radiazioni provenienti dal sole. Nel corso degli anni, sono stati registrati cambiamenti nel campo magnetico terrestre da minerali ricchi in ferro interessati da influenze magnetiche. Quando i minerali rimangono intrappolati sul posto, diventano come istantanee nel tempo del mutevole campo magnetico terrestre. Tuttavia, le «istantanee» possono essere sfocate qualora siano presenti piccole quantità di minerali che non sono buoni registratori. Utilizzando una tomografia micro-magnetica non distruttiva all’avanguardia, il progetto MIMATOM prevede di ingrandire i singoli minerali anziché la massa, fornendo così un quadro più chiaro dei cambiamenti del campo magnetico nel tempo. La loro comprensione ci consentirà di prevedere con maggiore precisione il futuro della nostra bolla magnetica.

Obiettivo

Our knowledge on the past behavior of the Earth’s magnetic field critically depends on our ability to obtain and interpret magnetic signals from geological materials such as lavas. These materials contain mixtures of different magnetic minerals, some of which are good recorders of the Earth’s magnetic field, others are not. Even the presence of a small amount of minerals with adverse magnetic properties obscures the signal of good recorders, resulting in >80% of measurements of the past Earth’s magnetic field strength being flawed. Understanding the Earth’s magnetic field is pivotal for predicting the future of its shielding capacity against the Sun’s electromagnetically charged particles, which globally weakened by >20% over the last millennium.

With MIMATOM, I aim to establish an entirely new way to obtain paleomagnetic and rock-magnetic information from geological materials. I will go beyond measuring magnetizations of bulk samples by determining the magnetic moments of individual minerals embedded in these samples in a non-destructive way. Starting from my recent proof-of-concept of Micro-Magnetic Tomography (MMT), I will develop a radically new technique to assess magnetizations of individual minerals inside geological materials. This will enable understanding which minerals are reliable recorders of the Earth’s magnetic field by characterizing their magnetic behavior as function of their grain size, shape, and chemistry. Then I will use MMT to obtain paleomagnetic information from selections of minerals that I identified as good recorders and unlock information on the past state of the Earth’s magnetic field from even the most challenging and magnetically complex geological materials, such as lavas.

My revolutionary new technique will open archives of the past behavior of the Earth’s magnetic field that currently are inaccessible. Moreover, it will pave the way for radically new venues in paleomagnetic and rock-magnetic research, at mineral level.