Sample Petrographic Description
Sample Number | MCY 05231 |
Newsletter | 29,2 |
Location | MacKay Glacier |
Field Number | 17332 |
Dimensions (cm) | 3.0 x 1.0 x 1.25 |
Weight (g) | 6.16 |
Original Classification | CM1/2 Chondrite |
Updated Classification | CM2 Chondrite |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 0-33;Ferrosilite (mol%): 1-40 | |
Weathering | |
B | |
Fracturing | |
A/B | |
Macroscopic Description - Kathleen McBride | |
The exteriors have some purplish black fusion crust with polygonal fractures. The interiors have a soft black matrix with light colored chondrules/inclusions. | |
Thin Section Description (,2) - Tim McCoy, Emma Bullock | |
The sections consist of rare small chondrules and individual silicates in a highly-altered matrix. Olivine compositions are Fa0-33, pyroxene is Fs1-40. The matrix consists pre-dominantly of an Fe-rich serpentine. The meteorites are CM1-2 chondrites. | |
Reclassification Notes (AMN 46,2) | |
MCY 05231 was classified as a CM1/2 in AMN vol.29, no. 2, and paired with MCY 05234. Since then, King et al. (2017) and Greenwood et al. (2019) have shown that MCY 05231 is actually a CM2, based on its lower phyllosilicate content than expected for CM1/2 and more similar oxygen to other CM2. | |
Notes | |
MCY 05231 was classified as a CM1/2 in AMN vol.29, no. 2, and paired with MCY 05234. Since then, King et al. (2017) and Greenwood et al. (2019) have shown that MCY 05231 is actually a CM2, based on its lower phyllosilicate content than expected for CM1/2 and more similar oxygen to other CM2. It is likely instead paired with other CM2 recovered in the South Mackay Glacier Icefields MCY 92500, 92502, MCY 05230, and MCY 05251 and well as CM2 recovered in South Mackay Glacier by PNRA in 2014 - MCY 14001, MCY 14004, and MCY 14014 samples. |
Antarctic Meteorite Images for Sample MCY 05231 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample MCY 05231 | ||||
Thin Section Photo(s) : | ||||
References for Sample MCY05231 | |
Sridhar, S., Bryson, J. F, King, A. J., & Harrison, R. J., 2021, Constraints on the ice composition of carbonaceous chondrites from their magnetic mineralogy. Earth and Planetary Science Letters, 576, 117243. | |
Bates, H.C., King, A.J., Donaldson Hanna, K.L., Bowles, N.E., Russell, SS., 2020, Linking mineralogy and spectroscopy of highly aqueously altered CM and CI carbonaceous chondrites in preparation for primitive asteroid sample return. Meteoritics & Planetary Science, 55, 77–101, doi: 10.1111/maps.13411. | |
King, A. J., Schofield, P. F., & Russell, S. S. , 2017, Type 1 aqueous alteration in CM carbonaceous chondrites: Implications for the evolution of water?rich asteroids. . Meteoritics & Planetary Science, 52, 1197-1215, doi: 10.1111/maps.12872. |