... band as well as the calculated Raman spectral curvature. Estimated temperatures appear to correlate well with the assigned petrologic types. We have calculated higher peak metamorphic temperatures for the CV3 chondrites than for the considered CO3 chondrites and further showed that the peak metamorphic...

...Figure 1. Representative BSE images of CO3 chondrites (upper part) and their corresponding combined X-ray maps (lower part). All scale bars are 250 µm. Colors for opaque minerals in X-ray maps: green-yellow refers to kamacite; bluish green refers to magnetite; blue refers to pyrrhotite; orange...

... on location (primarily latitude) while the magnitude of the weathering is dependent on many factors, with some meteorites (e.g., highly reduced enstatite chondrites and the matrix-rich CO3s) particularly susceptible to such effects. Figure 2. Schematic plot of ranges of oxygen isotopic compositions...

... by reaction with C-H-O fluids. In the CO3 chondrite Allan Hills 77307, cohenite occurs as grains <30 μm in kamacite ( Shibata 1996 ). PC cohenite contains up to ~4 wt% Ni ( Scott and Jones 1990 ). PC haxonite containing up to ~5 wt% Ni occurs with PC cohenite in the carbide-magnetite assemblages...

... )—an alteration that Berger et al. (2016) determined occurs in an aqueous environment at T < 135 °C; and it replaces troilite in chondrules in CO3 chondrites ( Scott and Jones 1990 ). In CV chondrites, secondary pentlandite is found in Fremdlinge ( El Goresy et al. 1978 ); it is the dominant sulfide in so...

... observations of magnetite plaquettes in carbonaceous chondrites (CC) that were made with scanning electron microscopy and synchrotron X-ray computed microtomography (SXRCT). We obtained the crystal orientation of the plaquettes using electron backscatter diffraction (EBSD) analysis. SXRCT permits visualization...

... are commonly metamorphosed). Even the CO3 and CV3 groups have commonly been subjected to temperatures of several hundred degrees Celsius, which can destroy or transform primitive matrix mineralogy. A debate has raged among those studying CR chondrites about the extent of alteration in this class, but many...

... is an unshocked iron ( Buchwald 1975 ) and graphite was not observed in the section. Iron carbides have also been observed in other meteorites: e.g., ureilites ( Goodrich et al. 2013 , 2014 ), type-3 ordinary chondrites ( Taylor et al. 1981 ; Krot et al. 1997 ; Keller 1998 ) and CO3 chondrites ( Scott...

... chondrites (solid line), CV3 chondrites (dashed line), and CO3 chondrites (dotted line) are also shown. Note that a large number of Type II particles contain UOC-related, high-MnO and low-Cr 2 O 3 olivines. Fields are derived from Brearley and Jones (1998) and references therein. ...

.... –5.8‰) and δ 13 C = 0 to –0.4‰ (ave. –0.2‰), relative to PDB. Chondrite-normalized REE (rare earth element) patterns from homogeneous dull and irregularly luminescent dolomites are very similar. They show negative Ce and Eu anomalies and light REE enrichment, which are similar to chondrite-normalized...

..., they represent extremely Si-undersaturated lithologies. Apart from its rare findings in the terrestrial environment, hibonite is known in meteorites and interplanetary dust. It is rather common in Ca,Al-rich inclusions and microspherules in chondrites ( e.g., Keil & Fuchs, 1971 ; Bischoff et al...

.... ( B ) IOM residue from the aqueously altered (CR2) chondrite Elephant Moraine (EET) 92042. Several solid and hollow nanoglobules (white arrows) are visible against a background of IOM mesoparticles. ( C ) A hollow nanoglobule (white arrow) in IOM from the heated (CO3) chondrite Dominion Range (DOM...

... olivine inclusions in CO3 chondrites: Relationship to parent-body aqueous alteration. Meteoritics and Planetary Science , 37 , 1781 –1796. Deer, W.A., Howie, R.A., and Zussman, J. ( 1978 ) Rock-forming Minerals, Volume 2A—Single-chain Silicates, 668 p. Wiley, New York. Devaraju, T.C...