Description
WriteupWriteup from MB 91:
Northwest Africa 2965
Algeria
Find: August 2004
Enstatite chondrite (EL6/7)
History and physical characteristics: Hundreds of fragments that weigh >100 kg were collected in the Algerian desert in 2004. Small fragments (~100 g) are commonly weathered to a dark brown with very dark weathering veins. Large pieces may retain portions of weathered fusion crust with only moderate to lightly weathered interiors.
Petrography: (T. Bunch and J. Wittke, NAU) A completely recrystallized enstatite chondrite with polygonal to irregular grain outlines. The grain size varies from 0.02 to 0.7 mm. Round, curved, blocky objects contain coarser-grained orthopyroxene than in the matrix. No relict chondrules were observed in ~32 cm2 that were analyzed. Metal, daubreelite, and tiny, vermicular grains of graphite are also present and constitute <3 vol%.
Mineral compositions: Orthopyroxene (Fs98.4±0.02 [sic]), plagioclase (An17.8Or4.4), troilite with Ti = 0.91, Cr = 1.10, Zn = 0.6 (all wt%).
Classification: Enstatite chondrite (EL6/7); minimal shock, variable weathering (W2–W5). It has absolutely no evidence of chondrules.
Type specimen: A 24 g sample is on deposit at NAU. Turecki and Reed hold the main mass.
