Dhofar 733 & 1766
733 in the field
credit: anonymous finder)
very small block of Dhofar 733
credit: Randy Korotev)
1766 in the field
credit: anonymous finder)
faces of 2 slices of Dhofar 1766. Millimeter ticks for scale. The
lightest-colored regions are vesicles filled with terrestrial alteration
minerals like gypsum and celestite. Click on image for enlargement.
of a thick (100 µm, top) and thin (35µm, bottom) section of Dhofar 1766.
Maximum width: 12 mm.
Bulletin, No. 87, Meteoritics
& Planetary Science 38,
Found: 2002 November 12
Mass: 98 g
meteorite (anorthositic granulitic breccia)
brownish grey stone weighing 98 g was found in the Dhofar region of Oman.
and classification (S. Demidova, Vernad;
MNHV): fusion crust is absent; the rock contains relics of mineral and
lithic clasts and shows granoblastic or poikiloblastic textures;
anorthositic, troctolitic and gabbro-noritic lithologies are present.
compositions: feldspar, An89-96;
orthopyroxene, Wo4-5En73-76; clinopyroxene, Wo36-40En48-52;
olivine, Fo71-76 (Fe/Mn ~87 at). Accessory minerals are
armalcolite, ilmenite, Al-Chromite, Ca-phosphate, troilite, and FeNi metal
(31-43 wt% Ni; 1.3-1.7 wt% Co); lath-shaped armalcolite is most common; the
stone is moderately weathered; smectite, gypsum, and Fe hydroxides are
present. Dho 733 was found far away from other lunar stones collected in
the Dhofar region and has a distinctly different texture. It is probably
not paired with any other Dhofar lunar finds known so far.
type specimens of 20 g, and a thin section, Vernad;
main mass with anonymous finder.
The Meteoritical Bulletin, No.
Found: 2011 December 9
Mass: 292 g
Lunar meteorite (feldspathic breccia)
Found by a prospector in December 2011.
characteristics: Angular 5 × 4 × 3 cm stone (292 g) with
shiny, reddish exposure surface and bluish-grey basal surface. On surface
~5 mm rounded, knobby, yellowish-white to dark grey, partly melted clasts
are embedded in a flow-textured groundmass, which has abundant, sub-mm
Wittmann and P.Carpenter,
Melt rock with flow texture of aphanitic melt enclosing 5 to <0.5 mm
size clasts of feldspar-rich rocks. All clasts are recrystallized but
retain outlines of original textures of poikilitic to subhedral mafic
silicates in plagioclase-dominated groundmass. Groundmass plagioclase forms
dense masses of tabular, felty textured crystals
with <10 µm skeletal pyroxene crystals filling interstices. Olivine
occurs up to 50 µm, zoned, subhedral crystals in the melt groundmass, and in
partly assimilated clasts is overgrown with augite that poikilitically
encloses acicular plagioclase, silica-rich mesostasis and euhedral, up to
30 µm armalcolite crystals. Accessory troilite occurs in the melt
groundmass as round to oval, <10 µm crystals, some of which are
intergrown with minute taenite and tetratenite
grains; subhedral to granular, 30 to 250 µm
chromian spinel crystals exhibit variable ° of decomposition and
recrystallization. Abundant vesicles are hollow or occupied by secondary
gypsum, celestite, rare barite, and greenish-yellow, Mg-rich
phyllosilicates (talc?) that are rimmed by celestite.
N=21); olivine (Fa10-30, molar Fe/Mn=61-195; N=20); augite (Fs10-21Wo24-42,
molar Fe/Mn=34-40; N=3); armalcolite (up to 0.4 wt% ZrO2; n=6);
; n=3), troilite (up to 0.3 wt.% Ni; N=3), metal (36.5-45.5 wt% Ni, 1.3-1.4
wt% Co). Bulk
composition (R. Korotev, WUSL)
INAA of subsamples gave mean abundances of (in wt.%) FeO 2.9, Na2O
0.69, CaO 16, (in ppm) Sc 4.6, La 1.2, Sm 0.58, Eu 1.6, Yb 0.36, Th 0.08,
and 1.1 ppb Ir.
Lunar (feldspathic melt rock).
20.3 g of type material and one polished thin section are at UWB. The
remaining material is held by the anonymous finder.
Dhofar 733 and Dhofar 1766 are distinct in having concentrations of Na and
Eu about twice that typical of other feldspathic lunar meteorites as a result of more albitic plagioclase. Because they
are compositionally similar to each other and were
found in proximity to each other, I suspect that they are paired despite
the textural differences.
733 | 1766
Schematic Map of the Find Locations of the
Dhofar Lunar Meteorites
S. I., Nazarov M. A., Lorenz C. A., Kurat G., Brandstätter F., and Ntaflos Th. (2007) Chemical
composition of lunar meteorites and the lunar crust. Petrology 15
A. B., Korotev R. L., Jolliff B. L., and Zeigler R. A. (2008) Petrography
and geochemistry of Dhofar 733 – An unusually sodic, feldspathic lunar
meteorite (abstract). In Lunar
and Planetary Science XXXIX, abstract no. 1853, 39th Lunar and
Planetary Science Conference.
Korochantseva E. V., Buikin A. I., Hopp J., Korochantsev A. V., and Trieloff
M. (2016) 40Ar-39Ar results of lunar meteorites Dhofar
025, 280, 309, 730, 733, 1436, 1442, SaU 449, NWA 6888
(abstract). 79th Annual Meeting of the Meteoritical Society, abstract no.
R. L. (2005) Lunar
geochemistry as told by lunar meteorites. Chemie der Erde 65,
R. L. (2012) Lunar
meteorites from Oman. Meteoritics
& Planetary Science 47,
1365–1402. doi: 10.1111/j.1945-5100.2012.01393.x
Korotev R. L. (2017) Update (2012–2017) on lunar meteorites
from Oman. Meteoritics
& Planetary Science 52, 1251-1256.
data on Omanian lunar meteorites.
R. L. and Irving A. J. (2014) Keeping up
with the lunar meteorites — 2014 (abstract). 45th Lunar and Planetary
Science Conference, abstract no. 1405.
Y. A., Nazarov, M. A., Ott, U. (2004) Noble
gases in new lunar meteorites from Oman: Irradiation history, trapped
gases, and cosmic-ray exposure and K-Ar ages. Geochemistry
A., Korotev R. L., and Jolliff B. L. (2014) Third of a
kind — Impact melted lunar granulitic breccia meteorite Dhofar 1766
Lunar and Planetary Science Conference, abstract no. 1182.
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