Northwest Africa 3144 (NWA 3144)

Northwest Africa

Purchased: 2004 Aug

Classification: Carbonaceous chondrite (CV3)

History: Purchased by Greg Hupé in August 2004 from a dealer in Rissani, Morocco.

Physical characteristics: Very fresh subspherical stone (1053 g) with complete black fusion crust. Relatively large chondrules and white to pale pink CAI are present in a very fine grained dark matrix.

Petrography: (A. Irving and S. Kuehner, UWS; J. Boesenberg, Brown U) Well-formed chondrules (mostly granular but also some BO, apparent diameter 880 ± 330 µm , N = 25), relatively abundant amoeboid to irregularly-shaped, very fine grained CAI and sparse olivine-rich aggregates are set in a fine grained matrix (~20 vol.%, sepia brown in thin section). Olivine-rich chondrules and olivine-rich aggregates consist mainly of forsterite with minor enstatite, taenite, Cr-bearing magnetite (commonly associated with metal), troilite, pentlandite and rare copper metal (containing Mo and Sn). One barred olivine chondrule is surrounded by an olivine aggregate rim with embedded chondrule fragments. Several large CAI appear to be fluffy type A with cores composed of Mg-Al spinel (with variable Fe contents), grossular garnet, perovskite, fassaitic clinopyroxene, anorthite, sodalite (some Ca-bearing), and minor anorthoclase, ilmenite and Ni-Zn metal. Wark-Lovering rims on CAI consist of gehlenite, anorthite, spinel, olivine (~Fa₆₀), andradite garnet, hedenbergite, diopside, kirchsteinite(?) and awaruite (with measurable Pt and Rh).

Geochemistry: (J. Boesenberg, Brown U) Olivine (Fa_22.9±19.3, range Fa_0.5-45.7, N = 8), enstatite (Fs_2.3±2.0Wo_2.6±1.4, rangeFs_1.1-4.6Wo_1.0-3.4, N = 3), subcalcic augite (Fs_4.5Wo_30.7), plagioclase (An_87.8-93.8Or_0.0, N = 4).

Classification: Carbonaceous chondrite (CV3).

Specimens: 20 g at AMNH; 1.6 g at PSF converted to a polished thin section; one polished thin section at UWB; remainder with Mr. G. Hupé.