Lunar Meteorite: Dhofar 733 & 1766

paired stones

Dhofar 733 in the field. Photo credit: anonymous finder
Dhofar 1766 in the field. Photo credit: anonymous finder
Two small samples of Dhofar 733. Photo credits: Randy Korotev (left) and Norbert Classen (right)
Sawn faces of 2 slices of Dhofar 1766. Millimeter ticks for scale. The lightest-colored regions are vesicles filled with terrestrial alteration minerals gypsum and celestine. Photo credit: Randy Korotev
Images of a thick (100 µm, top) and thin (35µm, bottom) section of Dhofar 1766. Maximum width: 12 mm. Photo credit: Randy Korotev
False-color image of a ~2-mm piece of Dhofar 733. Red = plagioclase, green = olivine, and blue = pyroxene. The brownish areas are void spaces. Image credit: Ryan Zeigler.
from The Meteoritical Bulletin, No. 87

Dhofar 733

Oman
Found: 2002 November 12
Mass: 98 g (1 piece)

Classification: Lunar meteorite (anorthositic granulitic breccia)

History: A brownish grey stone weighing 98 g was found in the Dhofar region of Oman.

Mineralogy and classification (S. Demidova, Vernad; G. Kurat, 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.

Mineral compositions: feldspar, An89-96; orthopyroxene, Wo4-5E73-76; clinopyroxene, Wo36-40, En48-52; 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.

Specimens: type specimens of 20 g, and a thin section, Vernad; main mass with anonymous finder.
from The Meteoritical Bulletin, No. 102

Dhofar 1766

Zufar, Oman
found: 2011 December 9
Mass: 292 g (1 piece)

Classification: Lunar meteorite (feldspathic breccia)

History: Found by a prospector in December 2011.

Physical 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 vesicles.

Petrography: (A. Wittmann and P. Carpenter, WUSL) 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 tetrataenite 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.

Geochemistry: (A. Wittmann, WUSL): Plagioclase (An77-96Ab13.9-3.4Or0-0.7; 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); spinel (Mg3.65–4.84Al6.48–12.77Fe3.24–4.57Ti0.37–0.65Cr2.57–8.44O32 ; 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.

Classification: Lunar (feldspathic melt rock).


Specimens: 20.3 g of type material and one polished thin section are at UWB. The remaining material is held by the anonymous finder.

Randy Says…

Compositionally, 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.

More Information

Meteoritical Bulletin Database

Dhofar 733 | 1766

Map

Schematic Map of  Find Locations of  Lunar Meteorite from Oman

References

Anand M., Taylor L. A., Patchen A., Cahill J., and Nazarov M. A. (2002) New minerals from a new lunar meteorite, Dhofar 280Lunar and Planetary Science XXXIII, abstract no. 1653.

Anand M., Taylor L. A., Nazarov M. A., Shu J., Mao H.-K., and Hemley R. J. (2004) Space weathering on airless planetary bodies: clues from the lunar mineral hapkeiteProceedings of the National Academy of Sciences 101, abstract no. 18, 6847-6851.

Bischoff A. (2001) Fantastic new chondrites, achondrites, and lunar meteorites as the result of recent meteorite search expeditions in hot and cold desertsEarth, Moon and Planets 85-86, 87-97.

Cahill J.T., Taylor L.A., Anand M., Patchen A., and Nazarov M.A. (2002) Mineralogy, petrography, and geochemistry of lunar meteorite Dhofar 081: New developmentsLunar and Planetary Science XXXIII, abstract no. 1351.

Cahill J. T., Floss C., Anand M., Taylor L. A., Nazarov M. A., and Cohen B. A. (2004) Petrogenesis of lunar highlands meteorites: Dhofar 025, Dhofar 081, Dar al Gani 262, and Dar al Gani 400Meteoritics & Planetary Science 39, 503-530.

Cohen B. A. (2005) More impact-melt clasts in feldspathic lunar meteorites. 68th Annual Meeting of the Meteoritical Society, abstract no. 5314.

Cohen B. A. (2008) Lunar meteorite impact melt clasts and lessons learned for lunar surface samplingLunar and Planetary Science XXXIX, abstract no. 2532, 39th Lunar and Planetary Science Conference.

Consolmagno G. J., Russell S. S., and Jeffries T. E. (2004) An in-situ study of REE abundances in three anorthositic impact melt lunar highland meteoritesLunar and Planetary Science XXXV, abstract no. 1370.

Demidova S. I., Nazarov M. A., Lorenz C. A., Kurat G., Brandstätter F., and Ntaflos Th. (2007) Chemical composition of lunar meteorites and the lunar crustPetrology 15 (4), 386-407. Fernandes V. A., Anand M., Burgess R., and Taylor L. A. (2004) Ar-Ar studies of Dhofar clast-rich feldspathic highland meteorites: 025, 026, 280, 303Lunar and Planetary Science XXXV, abstract no. 1514.

Fritz J. (2012) Impact ejection of lunar meteorites and the age of Giordano BrunoIcarus 221, 1183-1186.

Greshake A., Schmitt R. T., Stöffler D., Pätsch M., and Schultz L. (2001) Dhofar 081: A new lunar highland meteoriteMeteoritics & Planetary Science 36, 459-470.

Korochantseva E. V., Buikin A. I., Hopp J., Korochantsev A. V., and Trieloff M. (2015) Thermal history of lunar meteorite Dhofar 280. 46th Lunar and Planetary Science Conference, abstract no. 2136.

Korochantseva E. V., Buikin A. I., Hopp J., Korochantsev A. V., Ott U. and Trieloff M. (2015) Irradiation history of lunar meteorite Dhofar 280. 46th Lunar and Planetary Science Conference, abstract no. 2158.

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. 79th Annual Meeting of the Meteoritical Society, abstract no. 6317.

Korotev R. L. (2005) Lunar geochemistry as told by lunar meteoritesChemie der Erde 65, 297-346.

Korotev R. L. (2006) New geochemical data for a some poorly characterized lunar meteoritesLunar and Planetary Science XXVII, abstract no. 1404.

Korotev R. L. (2012) Lunar meteorites from OmanMeteoritics & Planetary Science 47, 1365-1402.

Korotev R. L. (2013) Siderophile elements in brecciated lunar meteorites44th Lunar and Planetary Science Conference, abstract no. 1028.

Korotev R. L. (2017) Update (2012–2017) on lunar meteorites from OmanMeteoritics & Planetary Science 52, 1251-1256. All Korotev data on Omani lunar meteorites.

Korotev R. L., Irving A. J., and Bunch T. E. (2008) Keeping up with the lunar meteorites – 2008Lunar and Planetary Science XXXIX, abstract no. 1209.

Lorenzetti S., Busemann H., and Eugster O. (2005) Regolith history of lunar meteoritesMeteoritics & Planetary Science 40, 315-327.

Macke R. J., Kiefer W. S., Britt D. T., Irving A. J., and Consolmagno G. J. (2011) Densities, porosities and magnetic susceptibilities of meteoritic lunar samples: Early results42nd Lunar and Planetary Science Conference, abstract no. 1986.

Macke R. J., Britt D. T., and Consolmagno G. J. (2011) Density, porosity and magnetic susceptibility of achondritic meteoritesMeteoritics & Planetary Science 46, 311-326.

Nazarov M. A., Badyukov D. D., Lorents K.A., Demidova. S. I. (2004) The flux of lunar meteorites onto the EarthSolar System Research 38, 49-58.

Nazarov M. A., Demidova S. I., Ntaflos Th., and Brandstaetter F. (2014) Origin of native silicon and Fe-silicides in lunar rocks. 45th Lunar and Planetary Science Conference, abstract no. 1090.

Nishiizumi K. (2003) Exposure histories of lunar meteorites. Evolution of Solar System Materials: A New Perspective from Antarctic Meteorites, 104.

Nishiizumi K. and Caffee M. W. (2006) Constraining the number of lunar and martian meteorite falls. 69th Annual Meeting of the Meteoritical Society, abstract no. 5368.

Nishiizumi K., Hillegonds D. J., McHargue L. R., and Jull A. J. T. (2004) Exposure and terrestrial histories of new lunar and martian meteorites, In Lunar and Planetary Science XXXV, abstract no. 1130.

Rochette P., Gattacceca J., Ivanov A. V., Nazarov M. A., and Bezaeva N. S. (2010) Magnetic properties of lunar materials: Meteorites, Luna and Apollo returned samplesEarth and Planetary Science Letters 292, 383-391.

Russell S. S., Joy K. H., Jeffries T. E., Consolmagno G. J., and Kearsley A. (2014) Heterogeneity in lunar anorthosite meteorites: implications for the lunar magma ocean modelPhilosophical Transactions of the Royal Society A 372: 20130241. http://dx.doi.org/10.1098/rsta.2013.0241

Shukolyukov Y. A., Nazarov M. A., Pätsch M., and Schultz L. (2001) Noble gases in three lunar meteorites from OmanLunar and Planetary Science XXXII, abstract no. 1502.

Shukolyukov Y. A., Nazarov M. A., and Ott U. (2004) Noble gases in new lunar meteorites from Oman: Irradiation history, trapped gases, and cosmic-ray exposure and K-Ar ages. Geochemistry International 42, 1001-1017.

Warren P. H., Taylor L. A., Kallemeyn G., Cohen B. A., Nazarov M. A. (2001) Bulk-compositional study of three lunar meteorites: Enigmatic siderophile element results for Dhofar 026Lunar and Planetary Science XXXII, abstract no. 2197.

Warren P. H., Ulff-Møller F., and Kallemeyn G. W. (2005) “New” lunar meteorites: Impact melt and regolith breccias and large-scale heterogeneities of the upper lunar crustMeteoritics & Planetary Science 40, 989-1014.