Magnetic Classification of Antarctic Achondrites

• Main Author: Nagata, Takesi
• Language: English
• Published: 1980
• Subjects: Antarctic; Antarc*; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/record/1102/files/KJ00000011628.pdf

P(論文) The magnetic hysteresis curves and the thermomagnetic curves of 17 Antarctic achondrites are measured. The saturation magnetization (I_s) of 3 ureilites ranges 2.2-6.4emu/gm while I_s is smaller than 0.53emu/gm for 7 diogenites, 6 eucrites and 1 howardite. By the thermomagnetic analysis, the I_s value of each achondrite is resolved into the saturation magnetization of kamacite, I_s (α), that of plessite, I_s (α+γ), that of taenite I_s (γ), and that of shreibersite, I_s (Ph). Results show that I_s (α)/I_s ≲ 0.40 for diogenites, whereas 1 ≳ I_s (α)/I_s ≳ 0.79 for eucrites and howardites, which indicate that Ni-content in metallic nickel-irons in diogenites is definitely larger than that in eucrites and howardites. On an I_s (α)/I_s versus I_s diagram, therefore, the three groups of achondrite are well separately grouped, just as so in the magnetic classification of chondrites. departmental bulletin paper