Compositions and taxonomy of 15 unusual carbonaceous chondrites

Spectral reflectance properties of carbonaceous chondrites: 8. “Other” carbonaceous chondrites: CH, ungrouped, polymict, xenolithic inclusions, and R chondrites

“…Clayton and Mayeda (1999) determined that GRO 95566 appears to be a CM2 chondrite, but has exceptional oxygen isotope composition. In comparison to CM2 chondrites, GRO 95566 is less altered (Choe et al, 2010). The spectrum of GRO 95566 is consistent with a carbonaceous meteorite containing Fe-poor mafic silicates (Fig.…”

“…Olivine compositions are Fa 1-39 , with many Fa 0-3 ; the matrix consists predominantly of an Fe-rich serpentine, and it was classified initially as a CM2 chondrite (McBride et al, 2001). It is an aqueously altered chondrite, but differs from CMs because its chondrules are larger; they are closer to CR chondrules in size (Huber et al, 2006;Choe et al, 2010). However, unlike CR chondrites, QUE 99038 contains little metal.…”

“…Some chondrules are rusty; it contains numerous small chondrules, some irregular aggregates, and many small silicate grains in a black matrix; trace amounts of metal and troilite are present as minute grains (McBride and Mason, 1997b). The silicate grains are almost entirely olivine near Fa 0 , with a few more Fe-rich grains up to Fa 35 (Choe et al, 2010); a little pyroxene of Fs 2-4 is also present (Choe et al, 2010), and the matrix appears to consist largely of Fe-rich serpentine (McBride and Mason, 1997b). Chondrule mesostatis has been altered to phyllosilicates (Choe et al, 2010).…”

“…The silicate grains are almost entirely olivine near Fa 0 , with a few more Fe-rich grains up to Fa 35 (Choe et al, 2010); a little pyroxene of Fs 2-4 is also present (Choe et al, 2010), and the matrix appears to consist largely of Fe-rich serpentine (McBride and Mason, 1997b). Chondrule mesostatis has been altered to phyllosilicates (Choe et al, 2010). Clayton and Mayeda (1999) determined that GRO 95566 appears to be a CM2 chondrite, but has exceptional oxygen isotope composition.…”

Shock effects in “EH6” enstatite chondrites and implications for collisional heating of the EH and EL parent asteroids

“…For standards we used the Allende meteorite (Jarosewich et al, 1987), the USGS international reference materials GSP-1 and BHVO-1 (Govindaraju, 1994), and the North Chile (Filomena) IIAB iron meteorite. Analyses were carried out following a protocol similar to that described in Kallemeyn et al (1989) and Choe et al (2010). …”