from The
Meteoritical Bulletin, no. 89, Meteoritics & Planetary Science
40, A201-A263 (2005)
Northeast Africa 001
Sudan
Found 2002 April
Lunar meteorite (anorthositic regolith breccia)
A brownish grey stone weighing 262 g was found by a prospector in northern
Sudan near the Libya/Egypt/Sudan boundary in 2002 April. Fusion crust is
absent, fresh surface is grey to dark
grey, and terrestrial alteration products are present at the meteorite edges
and in penetrating cracks and veins. Classification and mineralogy (J. Haloda
and P. Tycova, PCU): a clast-rich anorthositic regolith breccia
containing numerous mineral fragments and lithic clasts embedded in a well-consolidated
microcrystalline impact melt matrix. Lithic clasts (up to 1 cm in size)
are
mainly of anorthositic lithologies; impact-melt breccias of anorthositic
composition are abundant and show commonly breccia-in-breccia textures.
Fragments of primary igneous rocks of anorthositic to gabbroic composition
are common, containing plagioclase, An95.1-97.2, low-Ca pyroxene,
En46-65 Wo2.1-5, high-Ca pyroxene, En35-48Wo37-44,
and rare olivine, Fo79.4. Sparse clasts of mare basalts (consisting
of pigeonite plus anorthite plus accessory ilmenite), and glass fragments
and spherules are present. Mineral fragments are of various composition:
feldspar, An92-99; orthopyroxene, Wo2-4En49-80;
clinopyroxene, Wo9-39En50-87; olivine, Fo48-82
(Fe/Mn 93-100 atom%); accessory minerals are Mg-Al spinel, chromite, ilmenite
(2-5 wt% MgO), troilite, FeNi metal and silica. Several pyroxene grains
have marginal symplectitic intergrowths of fayalite+ hedenbergite+silica
after former pyroxferroite. Composition of the impact-melt matrix is (wt%):
SiO2 = 45.7, Al2O3 = 24.1, FeO = 7.2, MgO
= 7.4, CaO = 14.6, Na2O = 0.5, TiO2 = 0.5. Secondary
calcite, barite, gypsum and Fe hydroxides occur in cracks. Specimens: type
specimen, 20 g, and one polished thin section, PCU; 5.8 g, and
one polished thin section, UWS; 59.66 g, ROM; 60 g, Hupé;
9.7 g, Gregory; main mass with finder. |
