Sample Petrographic Description
| Sample Number | RBT 04133 |
| Newsletter | 31,1 |
| Location | Roberts Massif |
| Field Number | 16216 |
| Dimensions | 7.1 x 6.2 x 5.8 |
| Weight | 459.400 |
| Original Classification | CR2 Chondrite |
| Updated Classification | CV3 Chondrite (Reduced) |
| Mineral Composition (%Fa & %Fs) | |
| Fayalite (mol%): 1-12;Ferrosilite (mol%): 1-2 | |
| Weathering | |
| B/C | |
| Fracturing | |
| A/B | |
| Macroscopic Description - Cecilia Satterwhite | |
| Black fusion crust covers 40% of the meteorite’s exterior surface. Abundant white inclusions (some very large) are visible on the exterior. Other smaller inclusions are gray and some are weathered. Areas without fusion crust are grayish black with brown weathered areas. Fractures penetrate the surface. The interior is a coarse grained matrix, weathered a rusty brown with some gray areas visible. Abundant white, gray and rusty inclusions/chondrules are visible on the interior. | |
| Thin Section Description (,2) - Tim McCoy, Linda Welzenbach, Cari Corrigan | |
| The section exhibits large (up to 2 mm), well-defined chondrules and CAI’s in a dark matrix of FeO-rich phyllosilicate. Metal is present in only modest abundances. Weathering is moderate. Silicates are unequilibrated; olivines range from Fa1-12, with many Fa0-2, and pyroxenes from Fs1-2. The meteorite is a CR2 chondrite. | |
| Reclassification Notes (AMN 38,2) | |
| RBT 04133 was classified as a CR2 in the February 2008 (Vol.31 No. 1) newsletter. More detailed information has led to a better understanding of this sample, which we here re-classify to CV3 (reduced), based on the study of Davidson et al. (2014) Meteoritics and Planetary Science 49, No. 12, 2133–2151. Quoting from their paper: “Data presented here conflict with its initial classification as a CR2. Petrographically, RBT 04133 appears to be a CV3red, based on the presence of large CAIs and chondrules, the apparent lack of magnetite, and a matrix composition of Fa59–60. This is in agreement with its whole-rock C, N, and O-isotope compositions, and the Raman spectral characteristics of its IOM.” | |
| Antarctic Meteorite Images for Sample RBT 04133 | ||||
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| References for Sample RBT04133 | |
| Deng, Z., Moynier, F., van Zuilen, K., Sossi, P. A., Pringle, E. A., & Chaussidon, M., 2018, Lack of resolvable titanium stable isotopic variations in bulk chondrites. , Geochimica et Cosmochimica Acta, 239 , 409-419 . | |
| Garenne, A., Beck, P., Montes-Hernandez, G., Brissaud, O., Schmitt, B., Quirico, E., Howard, K. T., 2016, Bidirectional reflectance spectroscopy of carbonaceous chondrites: Implications for water quantification and primary composition. , Icarus, 264 , 172-183 , https://doi.org/10.1016/j.icarus.2015.09.005 . | |
| Bonal, L., Quirico, E., Flandinet, L., Montagnac, G., 2016, Thermal history of type 3 chondrites from the Antarctic meteorite collection determined by Raman spectroscopy of their polyaromatic carbonaceous matter. , Geochimica et Cosmochimica Acta, 189 , 312-337 . | |
| Davidson, J., Verchovsky, A., Schrader, D. L., Alexander, C. M. O'D., Lauretta, D. S., Busemann, H., Franchi, I. A., Greenwood, R. C., Connolly, H. C., Domanik, K. J., 2014, Petrography, stable isotope compositions, microRaman spectroscopy, and presolar components of Roberts Massif 04133: A reduced CV3 carbonaceous chondrite. , Meteoritics & Planetary Science, 49 , 2133-2151 . | |
| Valdes, M. C., Moreira, M., Foriel, J., Moynier, F., 2014, The nature of Earth's building blocks as revealed by calcium isotopes. , Earth and Planetary Science Letters, 394 , 135-145 . | |
| Beck, P., Garenne, A., Quirico, E., Bonal, L., Montes-Hernandez, G., Moynier, F., Schmitt, B., 2014, Transmission infrared spectra (2-25 µm) of carbonaceous chondrites (CI, CM, CV-CK, CR, C2 ungrouped): Mineralogy, water, and asteroidal processes , Icarus, 229 , Feb-14 , 263-277 , ISSN 0019-1035 , http://dx.doi.org/10.1016/j.icarus.2013.10.019 . | |
| Garenne, A., Beck, P., Montes-Hernandez, G., Chiriac, R., Toche, F., Quirico, E., Bonal, L., Schmitt, B., 2014, The abundance and stability of "water" in type 1 and 2 carbonaceous chondrites (CI, CM and CR) , Geochimica et Cosmochimica Acta, 137 , 15-Jul-14 , 93-112 , ISSN 0016-7037 , http://dx.doi.org/10.1016/j.gca.2014.03.034 . | |