Sample Petrographic Description
| Sample Number | LAP 02238 |
| Newsletter | 26,2 |
| Location | LaPaz Ice Field |
| Field Number | 15181 |
| Dimensions (cm) | 3.0 x 2.5 x 2.0 |
| Weight (g) | 26.55 |
| Original Classification | R Chondrite |
| Pairing | LAP 02238; LAP 03645 |
| Mineral Composition (%Fa & %Fs) | |
| Fayalite (mol%): 27-46;Ferrosilite (mol%): 18-36 | |
| Weathering | |
| B | |
| Fracturing | |
| A | |
| Macroscopic Description - Kathleen McBride | |
| 75% of the exterior has a shiny, black fusion crust. The bottom portion of the rock shows polygonal fractures. The exposed interior has weathered to a greenish-brown color. The interior is a gray matrix with white to light gray clasts 1-3 mm in length. Black clasts < 1 mm. This meteorite is moderately hard, with metal grains. Some rusty and oxidized areas are present. | |
| Thin Section Description (,4) - Tim McCoy, Linda Welzenbach | |
| The section consists of relatively few chondrules (up to 1 mm) and chondrule fragments in a fine-grained brecciated matrix, with very abundant iron sulfide and pentlandite and lesser abundances of oxides and graphite. Mineral compositions are olivine of Fa27-46 (most Fa38-40), orthopyroxene of Fs18-36Wo1-3 and augite Fs9-15Wo44-48. The olivine composition is similar to R chondrites, although graphite has not been previously reported in this group. | |
| Oxygen Isotopic Composition - T. K. Mayeda, Robert N. Clayton | |
| Our analysis for LAP 02238 gives: ? 18 O = +3.5 and ? 17 O = +4.5. This gives ? 17O of +2.7, in the range of R-chondrites, consistent with the very iron-rich olivine. The ? values are a little lower than the previous values seen in R chondrites (Y-75302). | |
| Antarctic Meteorite Images for Sample LAP 02238 | ||||
| Field Photo(s) : | ||||
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| Field photo image(s) courtesy of the ANSMET (ANtarctic Search for METeorites) Program, Case Western Reserve University and the University of Utah | ||||
| Antarctic Meteorite Images for Sample LAP 02238 | ||||
| Lab Photo(s) : | ||||
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| References for Sample LAP02238 | |
| Khan, R., Shirai, N., Ebihara, M., 2015, Chemical characteristic of R chondrites in the light of P, REEs, Th and U abundances. , Earth and Planetary Science Letters, 422 , 18-27 , http://dx.doi.org/10.1016/j.epsl.2015.04.008 . | |
| Isa, J., Rubin, A. E., Wasson, J. T., 2014, R-chondrite bulk-chemical compositions and diverse oxides: Implications for parent-body processes. , Geochimica et Cosmochimica Acta, 124 , 1-Jan-14 , 131-151 , ISSN 0016-7037 , http://dx.doi.org/10.1016/j.gca.2013.09.018 . | |
| Bischoff, A., Vogel, N., Roszjar, J., 2011, The Rumuruti chondrite group. , Chemie der Erde - Geochemistry, 71 Issue 2 , May-11 , 101-133 , ISSN 0009-2819 , http://dx.doi.org/10.1016/j.chemer.2011.02.005 . | |
| Rochette, P., Kohout, T., Pesonen, L., Quirico, E., Sagnotti, L., Skripnik, A., Gattacceca, J., Bonal, L., Bourot-Denise, M., Chevrier, V., Clerc, J. P., Consolmagno, G., Folco, L., Gounelle, M., 2008, Magnetic classification of stony meteorites: 2. Non-ordinary chondrites. , Meteoritics & Planetary Science, 43 , 959-980 , http://dx.doi.org/10.1111/j.1945-5100.2008.tb01092.x . | |
| Rubin, A. E., Huber, H., 2005, A weathering index for CK and R chondrites. , Meteoritics & Planetary Science, 40 , 1123-1130 , http://dx.doi.org/10.1111/j.1945-5100.2005.tb00178.x . | |
| Schultz, L., Weber, H. W., Franke, L., 2005, Rumuruti chondrites: Noble gases, exposure ages, pairing, and parent body history. , Meteoritics & Planetary Science, 40 , 557-571 , http://dx.doi.org/10.1111/j.1945-5100.2005.tb00963.x . | |
| Schultz, L., Franke, L., 2004, Helium, neon, and argon in meteorites: A data collection. , Meteoritics & Planetary Science, 39 , 1889-1890 , http://dx.doi.org/10.1111/j.1945-5100.2004.tb00083.x . | |
| RELAB, , Reflectance Experiment Lab , catalogue of samples, . | |