Saturation Magnetization Measurements of Carbonaceous Chondrites

The saturation magnetization of some carbonaceous chondrites was studied using a Faraday balance. The Faraday balance was shown to be an accurate (± 3%), reliable technique for measuring saturation magnetization by comparison with vibrating‐sample magnetometer measurements on the same samples. Hyman and Rowe (1983) previously used these saturation magnetization measurements to measure the magnetite content of the five CI chondrites. Here, we present measurements on the magnetite contents of some CM2, CV3 and a CV5 chondrites. The method was also used to measure the content of metallic nickel‐iron in Ornans, 3.4 ± 0.3%. Of the CM2 chondrites examined, only Bells, Essebi and Haripura had magnetite contents over about 1% by weight. A number of CV chondrites have magnetite between 2.3 and 13%, with little or no metallic iron. Leoville and Vigarano contain both magnetite and metallic iron, complicating the saturation magnetization results. Arch and Allende have very little metallic iron or magnetite, probably < 1% of either. This technique measures only ferrimagnetic magnetite; superparamagnetic magnetite with particle size < 300Å is ignored.