Northwest Africa 2644
Northwest Africa
Purchased 2004
Achondrite (howardite)
A 216 g dark, crusted stone was purchased in Erfoud,
Morocco in August 2004. Description and classification (T.
Bunch and J. Wittke, NAU): composed of typical cumulate
and basaltic eucrite clasts and large (up to 2.8 mm in
diameter), very dark shock-melt and breccia clasts of glass,
quench crystals, and shocked diogenite and eucrite fragments,
all set in a very light-colored and fine-grained matrix. In
addition, irregular to sub-rounded metal grains up to 3 mm in
diameter are present within the shocked clasts and randomly
distributed in the matrix. Diogenite orthopyroxene, Fs21.3?29
Wo0.8?3.1 (FeO/MnO = 24.5?32.4); shocked clast pigeonite,
Fs29.1?31.8Wo3.4?6.1 (FeO/MnO = 30.2=33.4); cumulate
pyroxene, Fs51.4?56.4Wo2.9?3.8; large plagioclase fragments,
An90?94.2; metal, Ni = 4.4?18.3 wt%. Low-grade weathering
and low level shock; shock-melt/breccia clasts experienced
high shock levels. Specimens: type specimen, 22.0 g NAU;
WJM
Szukaj a znajdziesz! W.J.Makocki