Sample Petrographic Description
Sample Number | GRO 95545 |
Newsletter | 19,2 |
Location | Grosvenor Mountains |
Field Number | 9797 |
Dimensions (cm) | 7.0 x 5.0 x 3.0 |
Weight (g) | 142.05 |
Original Classification | L3.5 Chondrite |
Updated Classification | L3.2 Chondrite |
Pairing | GRO 95502; GRO 95504; GRO 95505; GRO 95512; GRO 95539; GRO 95542; GRO 95544; GRO 95545; GRO 95546; GRO 95550; |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 1-20;Ferrosilite (mol%): 4-28 | |
Weathering | |
B | |
Fracturing | |
A | |
Macroscopic Description - Kathleen McBride | |
The exterior of these meteorites have thin, patchy fusion crust. In some areas fusion crust has been weathered away. The interior is dark brown with numerous chondrules. Chondrules are white to yellow in color and measure 1 to 4 mm in size. Some appear rusty. Metal grains are present and samples are very coherent and difficult to break. | |
Thin Section Description (,4) - Brian Mason | |
The sections are so similar that a single description will suffice; the meteorites are probably paired. The sections show numerous chondrules and chondrule fragments, up to 2.4 mm across, in a black matrix containing small amounts of nickel-iron and troilite. The chondrules are mainly granular and porphyritic olivine and olivine-pyroxene, with a few radiating and crytocrystalline pyroxene. Microprobe analyses show olivine and pyroxene of variable composition: olivine, Fa1-20, mean Fa14; pyroxene, Fs1-28. The meteorites are classified as L3 chondrites (estimated L3.5). | |
Reclassification Notes (AMN 44,2) | |
Reclassified as an L3.2 Chondrite based on Cr contents of Type II chondrule olivine. Pairing groups adjusted based on olivine composition and recovery location. Righter, K., Schutt, J., Lunning, N., Harvey, R., & Karner, J. (2021a) Identification and pairing reassessment of unequilibrated ordinary chondrites from four Antarctic dense collection areas. Meteoritics & Planetary Science 56, 1556-1578. | |
Notes | |
Righter et al. (2021) propose that GRO 95502, GRO 95504, GRO 95505, GRO 95512, GRO 95539, GRO 95542, GRO 95544, GRO 95545, GRO 95546, and GRO 95550 are all paired and type L3.2. |
Antarctic Meteorite Images for Sample GRO 95545 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample GRO 95545 | ||||
Thin Section Photo(s) : | ||||
References for Sample GRO95545 | |
Righter, K., Schutt, J., Lunning, N., Harvey, R, and Karner, J., 2021, Identification and pairing reassessment of unequilibrated ordinary chondrites from four Antarctic dense collection areas. Meteoritics & Planetary Science, 56, 1556-1573, doi: 10.1111/maps.13707. | |
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. | |
Quirico, E., Montagnac, G., Rouzaud, J. N., Bonal, L., Bourot-Denise, M., Duber, S., Reynard, B., 2009, Precursor and metamorphic condition effects on Raman spectra of poorly ordered carbonaceous matter in chondrites and coals. Earth and Planetary Science Letters, 287 Issues 1-2, 30-Sep-09, 185-193, ISSN 0012-821X, http://dx.doi.org/10.1016/j.epsl.2009.07.041. | |
Benoit, P. H., Akridge, G. A., Ninagawa, K., Sears, D. W. G., 2002, Thermoluminescence sensitivity and thermal history of type 3 ordinary chondrites: Eleven new type 3.0-3.1 chondrites and possible explanations for differences among H, L, and LL chondrites. Meteoritics & Planetary Science, 37, 793-805. |