Sample Petrographic Description
Sample Number | GRO 95602 |
Newsletter | 20,1 |
Location | Grosvenor Mountains |
Field Number | 7625 |
Dimensions (cm) | 4.3 x 3.6 x 1.0 |
Weight (g) | 51.50 |
Original Classification | Howardite |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 25;Ferrosilite (mol%): 17-49 | |
Weathering | |
A/B | |
Fracturing | |
A | |
Macroscopic Description - Cecilia Satterwhite | |
The exterior of this achondrite is covered with black fusion crust. The fusion crust is shiny on some surfaces, dull on others. A large black clast (1.2 cm) is present on the exterior. Smaller clasts are visible (0.5 cm). Areas devoid of fusion crust are gray with light and dark inclusions. Chipping revealed a fine grained gray interior, with abundant light and dark inclusions, ranging in size from 1 to 3 mm. Minor oxidation is visible in some areas. | |
Thin Section Description (,3) - Brian Mason | |
The section shows a groundmass of comminuted pyroxene and plagioclase (grains up to 0.3 mm) with a few larger plagioclase clasts (up to 2 mm). Microprobe analyses show that most of the pyroxene is hypersthene (Wo1-5, Fs22-36); one grain of augite, Wo42Fs32, was analyzed, and several grains of intermediate composition. Plagioclase composition is An86-91. One grain of olivine, Fa25, and one of an SiO2 polymorph were analyzed. The meteorite is a howardite, very similar to GRO95534, and 95535, and 95581, with which it is probably paired. | |
Notes | |
GRO 95602 was initially paired with four other GRO howardites – GRO 95534, GRO 95535, GRO 95574, and GRO 95581. The relations between these five howardites have been re-evaluated by Mittlefehldt et al. (2013), Cartwright et al. (2014) and Lunning et al. (2016). Based on petrography, mineralogy, petrology, and bulk composition, GRO 95534, GRO 95535, GRO 95574, and GRO 95581 are paired together; GRO 95602 has been removed from this pairing group and is unpaired. AMN 45, no. 2. |
Antarctic Meteorite Images for Sample GRO 95602 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample GRO 95602 | ||||
Thin Section Photo(s) : | ||||
References for Sample GRO95602 | |
Hahn, T. M., Lunning, N. G., McSween, H. Y., Bodnar, R. J., and Taylor, L. A., 2018, Mg-rich harzburgites from Vesta: Mantle residua or cumulates from planetary differentiation. Meteoritics & Planetary Science, 53, 514-546, doi: 10.111/maps.13036. | |
Moriarty, D. P., Pieters, C. M., 2016, Complexities in pyroxene compositions derived from absorption band centers: Examples from Apollo samples, HED meteorites, synthetic pure pyroxenes, and remote sensing data. Meteoritics & Planetary Science, 51(2), 207-234. | |
Lunning, N. G., Welten, K. C., McSween, H. Y., Caffee, M. W., Beck, A. W., 2016, Grosvenor Mountains 95 howardite pairing group: Insights into the surface regolith of asteroid 4 Vesta. Meteoritics & Planetary Science, 51(1), 167-194. | |
Mittlefehldt, D. W., 2015, Asteroid (4) Vesta: I. The howardite-eucrite-diogenite (HED) clan of meteorites. Chemie der Erde - Geochemistry, 75 Issue 2, Jun-15, 155-183, ISSN 0009-2819, http://dx.doi.org/10.1016/j.chemer.2014.08.002. | |
Cartwright, J. A., Ott, U., Mittlefehldt, D. W., 2014, The Quest for Regolithic Howardites Part 2: Surface Origins Highlighted by Noble Gases. Geochimica et Cosmochimica Acta, 140, 488-508. | |
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. | |
RELAB, , Reflectance Experiment Lab , catalogue of samples. |