Antarctic Search for Meteorites (ANSMET) Search this
Place:
Antarctica
Collection Date:
2009
Notes:
# NASA data for MIL 090723 Weathering: B Fracturing: B Pairing: MIL 07099 Fa: 0-55 mol %
The exteriors of these carbonaceous chondrites all have black/brown fusion crust exhibiting various forms of fracturing. Some of these meteorites have polygonal fractures, while others have penetrating cracks. All have areas of rusty brown oxidation. The interiors consist of uniform fine grained, black matrix with oxidation and light specks of white irregular inclusions/chondrules.
These meteorites are so similar that a single description suffices. The sections consist of abundant small (up to 1 mm) chondrules, chondrule fragments, and mineral grains in a dark matrix. Metal and sulfide occur within and rimming the chondrules. Glass within chondrules appears to be very clear/fresh. CAIs are abundant in many sections (mostly Type A), and range in size up to 1 mm, many containing blue hibonite grains. At least one compound CAI was found. AOAs up to 1 mm are present, as well. Olivine ranges in composition from Fa₀₋₆₅. Pyroxene analyses range from Fs₁₋₃₂ (most from Fs₁₋₇) Wo0.5-4. These meteorites are somewhat terrestrially altered. These are CO3 chondrites (likely type 3.0-3.2) and are probably members of the MIL 07099 pairing group.
