Advances in magneto-optical imaging applied to rock magnetism and paleomagnetism

作者：Uehara Minoru^*; van der Beek Cornelis Jacominus; Gattacceca Jerome; Skidanov Vladimir A; Quesnel Yoann

来源：Geochemistry Geophysics Geosystems, 2010, 11: Q05Y09.

DOI：10.1029/2009GC002653

• rock magnetism
• paleomagnetism
• magnetic microscopy
• magneto-optical imaging
• meteorite

We present results of the magneto-optical imaging technique applied to rock samples. This technique measures the magnetic flux threading a magneto-optically active film, which rotates the polarization direction of transmitted light (Faraday rotation) and is directly placed on the sample. Through the analyzer of a reflected light microscope, the vertical component of the surface magnetic field of the sample is observed and can be quantified through a specific calibration procedure. Owing to the thin magneto-optically active film (5 mu m) and the small sample-to-film distance (similar to 1 mu m), stray fields produced by magnetic grains in rocks carrying saturation isothermal remanent magnetization are successfully imaged with a spatial resolution of 10 mu m. We can also image the surface field distribution of rocks carrying natural remanent magnetizations by modulating the analyzer angle. In addition to its high spatial resolution, this technique offers a direct comparison between magnetic and reflected light images. Therefore, this new technique appears to be a powerful tool to map and identify the carriers of magnetic remanence in rock samples.

• 出版日期2010-5-12
• 单位中国地震局