Sample Petrographic Description
Sample Number | EET 87510 |
Newsletter | 11,2 |
Location | Elephant Moraine |
Field Number | 2632 |
Dimensions (cm) | 8.0 x 6.0 x 4.0 |
Weight (g) | 250.30 |
Original Classification | Howardite |
Pairing | EET 87509; EET 83376; EET 87510; EET 87518; EET 87531; EET 87532; EET 92022; EET 99400; EET 99408; |
Mineral Composition (%Fa & %Fs) | |
Ferrosilite (mol%): 21-54 | |
Weathering | |
B | |
Fracturing | |
B | |
Macroscopic Description - | |
All of these specimens retain at least a patch of fusion crust. EET 87513 is completely covered. All have a light gray matrix hosting a variety of angular clasts: fine-grained monomineralic clasts, coarse-grained feldspathic clasts, and aphanitic black clasts ranging from sub-mm to 2 cm in size. | |
Thin Section Description - | |
EET87503 ,2 shows a groundmass of comminuted pyroxene (orthopyroxene and pigeonite) and plagioclase (grains up to 0.3 mm) with a few larger mineral grains and rare polymineralic clasts up to 2.5 mm across. Opaques are present in small amounts. Microprobe analyses show a wide range in pyroxene composition: Wo1-22, Fs20-56, En24-76, but with orthopyroxene clustered around Wo2Fs23 and pigeonite around Wo12Fs50. Plagioclase composition is An88-95. In the field 87509, 87510, 87518, 87531 were noted as possibly paired. These, and EET 87513 closely resemble EET87503 ,2 and the same description applies to them. EET 87512 ,8 contains a clast, 9 x 3 mm, consisting of subequal amounts of plagioclase (An78-93) and pyroxene (slightly variable, average Wo7Fs33). These meteorites are howardites and are all very similar. | |
Notes | |
An initially defined pairing group (e.g., AMN 11, 2) consisting of EET 87503, EET 87509, EET 87510, EET 87512, EET 87518, and EET 87531 has been re-evaluated by Mittlefehldt et al. (2013). Based on petrography, mineralogy, petrology, bulk composition, and find locations, EET 87503 was removed from this group (and instead paired with EET 87513), and EET 87512 was removed from this group to be unpaired. The original group also gained EET 92002, EET 83376 (previously unpaired), EET 87532 (previously unpaired), and two from 1999 field season EET 99400 and EET 99408. Thus, the newly revised pairing groups are EET 87503 (503 and 513) and EET 87509 (EET 87509, EET 87510, EET 87518, and EET 87531, EET 87532, EET 83376, EET 92022, EET 99400 and EET 99408). EET 87512 is unpaired. |
Antarctic Meteorite Images for Sample EET 87510 | ||||
Thin Section Photo(s) : | ||||
References for Sample EET87510 | |
Mittlefehldt, D. W., Herrin, J. S., Quinn, J. E., Mertzman, S. A., Cartwright, J. A., Mertzman, K. R., Peng, Z. X., 2013, Composition and petrology of HED polymict breccias: The regolith of (4) Vesta. Meteoritics & Planetary Science, 48, 2105-2134, http://dx.doi.org/10.1111/maps.12182. | |
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. | |
Sears, D. W. G., Benoit, P. H., Sears, H., Batchelor, J. D., Symes, S., 1991, The natural thermoluminescence of meteorites: III. lunar and basaltic meteorites. Geochimica et Cosmochimica Acta, 55 Issue 11, Nov-91, 3167-3180, ISSN 0016-7037, http://dx.doi.org/10.1016/0016-7037(91)90481-J. |