Sample Petrographic Description
Sample Number | EET 87511 |
Newsletter | 11,2 |
Location | Elephant Moraine |
Field Number | 4814 |
Dimensions (cm) | 4.5 x 5.0 x 2.5 |
Weight (g) | 65.13 |
Original Classification | Ureilite |
Updated Classification | Ureilite (Aug-Bearing) |
Pairing | EET 87511; EET 87523; EET 87717; EET 96262; EET 96322; EET 96328; |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 15;Ferrosilite (mol%): 12 | |
Weathering | |
B | |
Fracturing | |
A | |
Macroscopic Description - Roberta Score and René Martinez | |
Two small patches of dull black fusion crust remain on EET87511. The exterior surface is greenish in color due to weathering. The interior is black with abundant platy minerals and some plagioclase. Oxidation occurs between the minerals. EET87523 is fairly coarse grained with a high proportion of mafic minerals. There is heavy oxidation in some areas but rust is absent in others. A few small patches of fusion crust remain. The same description applies to EET87717. | |
Thin Section Description (,2) - Brian Mason | |
Thin Section (EET87511,2; 87523,5; 87717,4) Description: Brian Mason EET87511,2 shows an aggregate of subhedral to anhedral grains (0.2-2.5 mm) of olivine with minor amounts of pyroxene. The grains are rimmed with black carbonaceous material containing a little nickel-iron and troilite. Microprobe analyses of EET87511 give the following compositions: olivine, Fa14; pyroxene, Wo5Fs12 ; one grain of augite, Wo36Fs9 with 4.7% Al2O3 was analyzed. The meteorite is relatively unshocked. EET87523,5 and EET87717,4 are very similar in texture and mineral compositions to EET87511. These meteorites are ureilites and are probably paired. | |
Reclassification Notes (AMN 17,1) | |
Thin sections of all ureilites were re-examined for AMN 17, no. 1 by P. Warren, in consultation with JM. Prinz and J. Jones. This sample was re-classified to augite-bearing ureilite because it contains significant augite. | |
Notes | |
This sample is now paired with a total of 5 others (EET 87511 group; in 2020 by K. Righter) based on field locations, textural similarities, and olivine minor and major element compositions (Goodrich, 2001, LPSC abstract, #1300; Downes et al., 2008, Geochim. Cosmochim. Acta 72(19), 4825-4844). |
Antarctic Meteorite Images for Sample EET 87511 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample EET 87511 | ||||
Thin Section Photo(s) : | ||||
References for Sample EET87511 | |
Beard, S. P., & Swindle, T. D. , 2017, Search for evidence of source event grouping among ureilites. . Meteoritics & Planetary Science, 52, 2343-2352, doi:10.1111/maps.12939. | |
Rochette, P., Gattacceca, J., Bourot-Denise, M., Consolmagno, G., Folco, L., Kohout, T., Pesonen, L., Sagnotti, L., 2009, Magnetic classification of stony meteorites: 3. Achondrites. Meteoritics & Planetary Science, 44, 405-427, http://dx.doi.org/10.1111/j.1945-5100.2009.tb00741.x. | |
Warren, P. H., Ulff-Møller, F., Huber, H., Kallemeyn, G. W., 2006, Siderophile geochemistry of ureilites: A record of early stages of planetesimal core formation. Geochimica et Cosmochimica Acta, 70 Issue 8, 15-Apr-06, 2104-2126, ISSN 0016-7037, http://dx.doi.org/10.1016/j.gca.2005.12.026. | |
Benoit, P. H., Sears, D. W. G., Akridge, J. M. C., Bland, P. A., Berry, F. J., Pillinger, C. T., 2000, The non-trivial problem of meteorite pairing. Meteoritics & Planetary Science, 35, 393-417. | |
Clayton, R. N., Mayeda, T. K., 1996, Oxygen isotope studies of achondrites. Geochimica et Cosmochimica Acta, 60 Issue 11, Jun-96, 1999-2017, ISSN 0016-7037, http://dx.doi.org/10.1016/0016-7037(96)00074-9. | |
Sandford, S. A., 1993, The mid-infrared transmission spectra of Antarctic ureilites. Meteoritics, 28, 579-585. | |
Goodrich, C. A., 1992, Ureilites: A critical review. Meteoritics, 27, 327-352. | |
Burns, R. G., Martinez, S. L., 1991, M”ssbauer spectra of olivine-rich achondrites-evidence for preterrestrial REDOX reactions. Proceedings Lunar and Planetary Science Conference, 21, 331-340. | |
Takeda, H., 1991, Comparisons of Antarctic and non-Antarctic achondrites and possible origin of the differences. Geochimica et Cosmochimica Acta, 55 Issue 1, Jan-91, 35-47, ISSN 0016-7037, http://dx.doi.org/10.1016/0016-7037(91)90397-N. | |
RELAB, , Reflectance Experiment Lab , catalogue of samples. |