Sample Petrographic Description
Sample Number | GRO 95645 |
Newsletter | 21,1 |
Location | Grosvenor Mountains |
Field Number | 9762 |
Dimensions (cm) | 1.0 x 1.0 x 1.5 |
Weight (g) | 2.42 |
Original Classification | C2 Chondrite |
Updated Classification | CM1 Chondrite |
Weathering | |
B/Ce | |
Fracturing | |
B | |
Macroscopic Description - Kathleen McBride | |
This carbonaceous chondrite has gray-black, fractured fusion crust. The fusion crust has a slight greenish cast under fluorescent lighting. Some areas are weathered and rusty. The interior reveals a black, fine-grained matrix with very little rust, but weathered evaporites. | |
Thin Section Description (,2) - Brian Mason | |
The section shows a close-packed aggregate of small chondrules (up to 0.2 mm across), chondrule fragments, and mineral grains with interstitial black matrix. The chondrules and mineral grains are made up of a fine-grained weakly birefringent material; microprobe analyses indicate that this material is probably an iron-rich serpentine. The meteorite is tentatively identified as a C2 chondrite. | |
Reclassification Notes (AMN 33,1) | |
Many carbonaceous chondrites were initially classified as C2 in early newsletters. Based on matrix properties, chondrule abundance and sizes, this sample has been reclassified more specifically here as CM1, because it exhibits more evidence for aqueous alteration than typical CM2s. |
Antarctic Meteorite Images for Sample GRO 95645 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample GRO 95645 | ||||
Thin Section Photo(s) : | ||||
References for Sample GRO95645 | |
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. |