Sample Petrographic Description
Sample Number | ALH 83018 |
Newsletter | 10,2 |
Location | Allan Hills |
Field Number | 2139 |
Dimensions (cm) | 2.5 x 1.7 x 4.0 |
Weight (g) | 3.70 |
Original Classification | E6 Chondrite |
Updated Classification | EL6 Chondrite |
Pairing | ALH 81021; ALH 81260; ALH 83018; |
Mineral Composition (%Fa & %Fs) | |
Ferrosilite (mol%): 0 | |
Weathering | |
B/C | |
Fracturing | |
A | |
Macroscopic Description - Carol Schwarz | |
This flat meteorite fragment has weathered fusion crust on the top and a weathered fracture surface on the bottom. The interior is dark and weathered. Metal is abundant | |
Thin Section Description (,2) - Brian Mason | |
Chondritic structure is barely discernable in the section, which consists largely of granular and prismatic enstatite (grains averaging 0.15 mm), with considerable nickel-iron, minor troilite and plagioclase, and traces of sinoite (Si2N2O, recognized by its high birefringence). Considerable weathering is indicated by areas of brown limonite and limonitic staining throughout the section. Fusion crust is present along one edge. Microprobe analyses show that the enstatite is almost pure MgSiO3 (FeO 0.1-0.2, CaO 0.7-0.8%); plagioclase is An14Or4; the nickel-iron contains 1.2% Si. The meteorite is an E6 chondrite, very similar to ALH81021 in all respects. | |
Reclassification Notes (AMN 17,1) | |
Re-classified based on information presented by Keil, K., 1989, Enstatite meteorites and their parent bodies, Meteoritics, 24, 195-208. |
Antarctic Meteorite Images for Sample ALH 83018 | ||||
Thin Section Photo(s) : | ||||
References for Sample ALH83018 | |
Rochette, P., Kohout, T., Pesonen, L., Quirico, E., Sagnotti, L., Skripnik, A., Gattacceca, J., Bonal, L., Bourot-Denise, M., Chevrier, V., Clerc, J. P., Consolmagno, G., Folco, L., Gounelle, M., 2008, Magnetic classification of stony meteorites: 2. Non-ordinary chondrites. Meteoritics & Planetary Science, 43, 959-980, http://dx.doi.org/10.1111/j.1945-5100.2008.tb01092.x. | |
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. | |
Keil, K., 1989, Enstatite meteorites and their parent bodies. Meteoritics, 24, 195-208. |