Magnetic classification of stony meteorites: 2. Non-ordinary chondrites

Abstract

A database of magnetic susceptibility (Chi) measurements on different non-ordinary chondrites (C, E, R, and ungrouped) populations is presented and compared to our previous similar work on ordinary chondrites. It provides an exhaustive study of the amount of iron-nickel magnetic phases (essentially metal and magnetite) in these meteorites. In contrast with all the other classes, CM and C show a wide range of magnetic material content, with a two orders of magnitude variation of Chi. Whether this is due to primary parent body differences, metamorphism or alteration, remains unclear. C3-4 and C2 yield similar Chi values to the ones shown by CK and CM, respectively. By order of increasing Chi, the classes with well-grouped Chi are: R << CO < CK is approximately equal to CI < Kak < CR < E is approximately equal to CH < CB. Based on magnetism, EH and EL classes have indistinguishable metal content. Outliers that we suggest may need to have their classifications reconsidered are Acfer 202 (CO), Elephant Moraine (EET) 96026 (C4-5), Meteorite Hills (MET) 01149, and Northwest Africa (NWA) 521 (CK), Asuka (A(+)-88198, LaPaz Icefield (LAP) 031156, and Sahara 98248 (R). Chi values can also be used to define affinities of ungrouped chondrites, and propose pairing, particularly in the case of CM and CV meteorites.