Lunar KREEP impact melt breccia - Dhofar 1442 alkali-rich
Find 2005; TkW: 120 g in total. Fusion crust absent.
Note: The mineralogy of this lunaite shows by far the highest Na2O value (appr. twice as high as all other lunaites) as well as K2O content (K2O: 0.76) of all known lunar meteorites. Most Lunaites have a K2O value of a seventh or less (of that of o 1442. Only Calcalong Creek and NWA 773 have a higher K2O value than the other lunars but still only a third of that of Dho 1442
Petrography: (Ivanova M.A., Lorenz C.A., and Nazarov M.A., Vernad.) Meteorite is a impact melt breccia containing lithic clasts, mineral fragments, glassy spherules, granulites and melt breccias embedded in a fine-grained melt matrix. It is a polymict breccia although the matrix/clasts ratio is varying from sample to sample of the meteorite. The lithic clasts population is presented by anorthosites, gabbroes, olivine gabbro-norites, gabbro-norites and norites. KREEPy and mare basalt clasts are present. The size of the clasts ranges from 0.02-8 mm; the main minerals are pyroxene and feldspar; minor - olivine, silica, chromite, ilmenite, Ca-phosphate, troilite and FeNi metal.
Geochemistry: (Ivanova M.A. and Kononkova N.N. (Vernad.) Chemical compositions of mineral phases are: feldspar An73-96Ab3.7-24.8; clinopyroxene En2.6-69.5Wo5.6-42.8 (Fe/Mn = 64 at.), orthopyroxene En60.8-77.1Wo1.2-4.1 (Fe/Mn = 69 at.), olivine Fo39.9-72.2 (Fe/Mn = 93 at.); ilmenite (MgO 5.5 wt%); FeNi metal (Ni 8.0 wt%; Co 0.6 wt%). Average glassy matrix composition (wt%): SiO2 49.6; TiO2 1.76; Al2O3 17.4; Cr2O3 0.20; FeO 10.7; MnO 0.15; MgO 7.16; CaO 11.1; Na2O 0.88; K2O 0.76; P2O5 0.84.
Classification: Achondrite (lunar KREEP impact melt breccia with minor features of weathering.
Specimens: A total of 21.8 g of sample and two thin sections are on deposit at Vernad. An anonymous buyer holds the main mass of the meteorite.
