|
|
Lunar Meteorite: Dhofar 1442Oman |
  Both sides of a slice of Dhofar 1442 (millimeter ticks for scale) (Photos by Randy Korotev) |
|
from The
Meteoritical Bulletin, no. 95, Meteoritics & Planetary Science 44,
429-462 (2009).Dhofar 1442OmanFind: 2005 Lunar (KREEP-rich? impact melt breccia) History: This meteorite was found in the desert of Oman. Physical characteristics: Five brownish to dark green stones weighing 106.5 g in total, with no fusion crust were located within two meters of each other. Petrography (Ivanova M. A., Lorenz C. A., and Nazarov M. A., Vernad): This meteorite is an impact melt breccia containing lithic clasts, mineral fragments, glassy spherules, granulites and melt breccias embedded in a fine-grained melt matrix. The breccia is polymict; matrix/clasts ratio varies from sample to sample of the meteorite. The lithic clast population includes anorthosites, gabbros, olivine gabbronorites, gabbro-norites and norites. KREEPy and mare basalt clasts are present. The size range of the clasts is 0.02–8 mm; major minerals are pyroxene and feldspar; minor minerals are olivine, silica, chromite, ilmenite, Ca-phosphate, troilite and FeNi metal. Geochemistry (Ivanova M. A. and Kononkova N. N. (Vernad): Feldspar is 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: Lunar (KREEP-rich impact melt breccia) with minor weathering. Type specimens: A total of 21.8 g and two thin sections are on deposit at Vernad. An anonymous buyer holds the main mass of the meteorite. Author's note: This rock is described above as containing glassy spherules. By definition, the rock is therfore a regolith breccia, not an impact-melt breccia (Stöffler et al., 1980). |
|
||||||||
