Dust from Mars Martian meteorite (Nakhlite) - 1 g - (1)

Hassi Messaoud 001 31°51.11’N, 6°58.59’E

Ouargla, Algeria

Find: 2020 Mar 11

Classification: Martian meteorite (Nakhlite)

Physical characteristics: Specimen is grayish-brown and displays a slightly weathered, minor fusion crust.

Petrography: (D. Sheikh, FSU) Specimen displays a cumulate texture (~1.1 mm grainsize) consisting primarily of compositionally zoned, prismatic or blocky (sometimes twinned) augite (displaying Fs-rich rims), ferroan olivine, and plagioclase; modal abundances: 75% augite, 15% plagioclase, 5% olivine. Accessory phases (modal abundance: 5%) are primarily found either in the mesostasis or within melt inclusions in augite or olivine grains; these phases include ferropigeonite, low-ca pyroxene, titanomagnetite, Si-Al-Na-Fe-K-rich glass, and fluorapatite.

Geochemistry: Olivine (Fa73.3±1.0, range Fa72.6-74.5, Fe/Mn = 50±1, n=3), Augite (Fs30.1±4.7Wo38.4±1.4, range Fs22.8-37.9Wo34.9-40.3, Fe/Mn = 32±4, n=47), Pigeonite (Fs58.6±4.9 Wo9.9±3.8, range Fs53.3-62.9 Wo6.6-14.0, Fe/Mn = 31±2, n=5), Low-Ca Pyroxene (Fs64.5±4.1Wo3.1±0.9, range Fs61.1-70.2Wo3.0-5.3, Fe/Mn = 35±2, n=8), Plagioclase (An37.2±1.3Or2.9±0.5, range An35.3-39.4Or2.0-4.0, n=27).

Classification: Martian (nakhlite). Sample is a martian meteorite due to the Fe/Mn ratios of olivine and pyroxene, and due to the plagioclase composition. Sample is a nakhlite due to the high modal abundance of augite and cumulate texture observed.

Specimens: 15.2 g at UCLA, main mass with Matthew Stream.