Sample Petrographic Description
| Sample Number | LAP 031275 |
| Newsletter | 29,2 |
| Location | LaPaz Ice Field |
| Field Number | 16190 |
| Dimensions (cm) | 2.75 x 1.25 x 1.25 |
| Weight (g) | 6.15 |
| Original Classification | R Chondrite |
| Updated Classification | R5 Chondrite |
| Mineral Composition (%Fa & %Fs) | |
| Fayalite (mol%): 17-42;Ferrosilite (mol%): 24 | |
| Weathering | |
| B/C | |
| Fracturing | |
| A | |
| Macroscopic Description - Kathleen McBride | |
| Brown/black fusion crust with oxidation halos covers 100% of this meteorite’s exterior surface. The interior has a gray matrix with rust and small black inclusions. | |
| Thin Section Description (,2) - Tim McCoy | |
| The section consist of rare, well-defined, chondrules (up to 1 mm) set in a recrystallized matrix of silicates and sulfides (both troilite and pentlandite). Olivines are nearly homogeneous (Fa38-42, with a small tail of analyses down to Fa17) and a singe pyroxene is Fs24. The meteorite is an R chondrite of type 5. | |
| Reclassification Notes (AMN 31,1) | |
| Reclassified as R5 Chondrite in AMN 31,1. | |
| Antarctic Meteorite Images for Sample LAP 031275 | ||||
| Field Photo(s) : | ||||
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| Field photo image(s) courtesy of the ANSMET (ANtarctic Search for METeorites) Program, Case Western Reserve University and the University of Utah | ||||
| References for Sample LAP031275 | |
| Schrader, D.L., Davidson, J., McCoy, T.J., Zega, T.J., Russell, S.S., Domanik, K.J., and King, A.J., 2021, The Fe/S ratio of pyrrhotite group sulfides in chondrites: An indicator of oxidation and implications for return samples from asteroids Ryugu and Bennu. , Geochimica et Cosmochimica Acta, 303 , 66–91 , https://doi.org/10.1016/j.gca.2021.03.019 . | |
| Lunning, N. G., Bischoff, A., Gross, J., Patzek, M., Corrigan, C. M., and McCoy, T. J., 2020, Insights into the formation of silica-rich achondrites from impact melts in Rumuruti-type chondrites. , Meteoritics & Planetary Science, 55 , 130-148 , doi: 10.1111/maps.13430. | |
| Schrader, D. L., Davidson, J., McCoy, T.J., 2016, Widespread evidence for high-temperature formation of pentlandite in chondrites. , Geochimica et Cosmochimica Acta, 189 , 2016 , 359–376 . | |
| Bischoff, A., Vogel, N., Roszjar, J., 2011, The Rumuruti chondrite group. , Chemie der Erde - Geochemistry, 71 Issue 2 , May-11 , 101-133 , ISSN 0009-2819 , http://dx.doi.org/10.1016/j.chemer.2011.02.005 . | |
| RELAB, , Reflectance Experiment Lab , catalogue of samples, . | |