Sample Petrographic Description
Sample Number | ALH 78165 |
Newsletter | 2,2 |
Location | Allan Hills |
Field Number | 469 |
Dimensions (cm) | ~3.5 x 3.0 x 1.5 |
Weight (g) | 20.86 |
Original Classification | Eucrite or Howardite |
Updated Classification | Eucrite (Polymict) |
Pairing | ALH 76005; ALH 77302; ALH 78040; ALH 78132; ALH 78158; ALH 78165; ALH 79017; ALH 80102; ALH 81006; ALH 81007; ALH 81008; ALH 81009; ALH 81010; ALH 81012; |
Mineral Composition (%Fa & %Fs) | |
Ferrosilite (mol%): 37-61 | |
Weathering | |
A | |
Fracturing | |
A | |
Macroscopic Description - | |
This is not a complete specimen. Shiny, black fusion crust covers only one surface. The other surfaces are fracture surfaces which have a medium gray matrix with <1 mm white clasts. A few of these clasts are weathered and yellow in color. When this stone was cleaved in half, a dark gray clast (~.5 cm) was exposed. This meteorite looks very similar in appearance to ALHA78158. | |
Thin Section Description - Brian Mason | |
Most of the section is an ophitic intergrowth of plagioclase-pigeonite breccia, with clasts up to 0.3 mm across. Fusion crust rims a considerable part of the section. Microprobe analyses of the ophitic portion shows pigeonite of fairly uniform composition, averaging Wo11Fs53En36, with a little ferroaugite (Wo38Fs32En30), and plagioclase ranging An83-90, average An86. Pyroxene in the breccia is pigeonite ranging from Wo8Fs37En55 to Wo8Fs61En31; one grain of ferroaugite, Wo44Fs29En27, was analyzed. The meteorite is a polymict pyroxene-plagioclase achondrite. | |
Reclassification Notes (AMN 3,2) | |
Re-classified as a polymict eucrite in AMN 3, no. 2. |
Antarctic Meteorite Images for Sample ALH 78165 | ||||
Lab Photo(s) : | ||||
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Antarctic Meteorite Images for Sample ALH 78165 | ||||
Thin Section Photo(s) : | ||||
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References for Sample ALH78165 | |
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. | |
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. | |
Marvin, U. B., MacPherson, G. J., 1989, Field and Laboratory Investigations of Meteorites from Victoria Land and the Thiel Mountains Region, Antarctica 1982-1983 and 1983-1984. Smithsonian Contributions to the Earth Sciences Number, 28, 146. | |
Scott, E. R. D., 1984, Pairing of meteorites found in Victoria Land, Antarctica. Memoirs of National Institute of Polar Research., Special issue 35, 102-125, http://ci.nii.ac.jp/naid/110000009967/en/. | |
Delaney, J. S., Prinz, M., Takeda, H., 1984, The polymict eucrites. Journal of Geophysical Research: Solid Earth, 89, C251-C288, http://dx.doi.org/10.1029/JB089iS01p0C251. | |
Delaney, J. S., Prinz, M., Takeda, H., 1983, Model comparison of Yamato and Allan Hills polymict eucrites. Memoirs of National Institute of Polar Research., Special Issue 30, 206-223, http://ci.nii.ac.jp/naid/110000009829/en/. | |
Hiroshi, T., Wooden, J. L., Mori, H., Delaney, J. S., Prinz, M., Nyquist, L. E., 1983, Comparison of Yamato and Victoria Land polymict eucrites: A view from mineralogical and isotopic studies. Journal of Geophysical Research: Solid Earth, 88, B245-B256, http://dx.doi.org/10.1029/JB088iS01p0B245. | |
Delaney, J. S., Takeda, H., Prinz, M., Nehru, C. E., Harlow, G. E., 1983, THE NOMENCLATURE OF POLYMICT BASALTIC ACHONDRITES. Meteoritics, 18, 103-111. | |
Marvin, U. B., Mason, B., 1982, Catalog of Meteorites from Victoria Land, Antarctica 1978-1980. Smithsonian Contributions to the Earth Sciences, 24, 97. |