Sample Petrographic Description
Sample Number | MET 00428 |
Newsletter | 24,2 |
Location | Meteorite Hills |
Field Number | 13040 |
Dimensions (cm) | 3.5 x 2.5 x 1.5 |
Weight (g) | 45.77 |
Original Classification | Iron-Ungrouped |
Pairing | MET 00428; MET 001038; |
Weathering | |
B | |
Fracturing | |
A | |
Macroscopic Description - Kathleen McBride | |
This 45.8 g ellipsoidal specimen has a frothy exterior. One end of the specimen exhibits a rounded depression. The end of the mass appears as if it may have been torn from another piece during atmospheric passage. | |
Thin Section Description - Tim McCoy | |
The section is dominated by Fe, Ni metal with 10-20 vol.% of rounded, elongate and ellipsoidal troilite inclusions that range in size from 200 microns to 2 mm in maximum dimension, with most less than 1 mm. The section is bounded by an α2 structure produced during atmospheric heating that extends up to 2 mm into the interior of the meteorite. Rare fusion crust is present. The frothy exterior resulted from a combination of atmospheric ablation and terrestrial weathering of the troilite inclusions. The troilite inclusions exhibit multiple twinning from deformation. No silicate or chromite inclusions were observed. Swathing kamacite surrounds the troilite inclusions. In areas of relatively few troilite inclusions, a weak Widmanstätten pattern is observed, with very thin kamacite lamellae (100-120 microns wide). Kamacite exhibits numerous Neumann bands and these bands are subsequently bent or, in many cases, sheared by subsequent microfaults. Large areas between kamacite bands are dominated by net or finger plessite. The classification of this meteorite is uncertain. Most other troilite-rich meteorites (e.g., Mundrabilla, LEW 86211, Soroti) differ significantly. The closest relative may be the fine octahedrite Mont Dieu, which is a member of group IIE. |
Antarctic Meteorite Images for Sample MET 00428 | ||||
Lab Photo(s) : | ||||
References for Sample MET00428 | |
Rubin, A.E., 2022, IIE irons: Origin, relationship to ordinary chondrites, and evidence for siderophile-element fractionation caused by chondrule formation, Meteoritics & Planetary Science, 57 (2), 163-184, doi: 10.1111/maps.13693. | |
Wasson, J. T. , 2017, Formation of non-magmatic iron-meteorite group IIE. . Geochimica et Cosmochimica Acta, 197, 396-416, http://dx.doi.org/10.1016/j.gca.2016.09.043. | |
Schrader, D. L., Lauretta, D. S., Connolly Jr., H. C., Goreva, Y. S., Hill, D. H., Domanik, K. J., Berger, E. L., Yang, H., Downs, R. T., 2010, Sulfide-rich metallic impact melts from chondritic parent bodies. Meteoritics & Planetary Science, 45, 743-758, http://dx.doi.org/10.1111/j.1945-5100.2010.01053.x. |