Dhofar 925 et al. - Lunar Meteorites

Lunar Meteorites: Dhofar 925, 960, & 961 (paired stones, reportedly)

Oman


A slice of Dhofar 961. Tick marks are spaces at 1 mm. (Photo by Randy Korotev. Click on image for enlargement) Sawn face of Dhofar 961. (Photo courtesy of Tony Irving. Thanks to Don Edwards for loan of the stone.) Exterior of Dhofar 961

Two sides of a slice of Dhofar 925. Tick marks are spaces at 1 mm. Despite the textural similarity between our samples of Dhofar 925 and Dhofar 961, Dhofar 961 is much more mafic and richer in incompatible elements. (Photo by Randy Korotev. Click on image for enlargement)
Slice and chips of Dhofar 960. (Thanks to Norbert Classen for the sample.)
End piece of Dhofar 960. 1 cm cube for scale. (Photograph courtesy of Michael Blood Meteorites)

Compositionally and texturally, our samples of Dhofar 925 and Dhofar 960 are just like SaU 449, allegedly collected ~210 km to the north. That's probably too far apart for the stones to be paired, unless the stones have or have been moved since they fell.

Our samples of Dhofar 925/960 and Dhofar 961 are different. Either the stones are not paired or the meteorite is very heterogeneous.

On the basis of composition and mineralogy, if we have a lunar meteorite from the giant South Pole-Aitken impact basin on the farside of the Moon, Dhofar 961 is the most likely candidate.

from The Meteoritical Bulletin, No. 88, Meteoritics & Planetary Science 39, A215-A272 (2004)

Dhofar 925

19°23.8' N, 54°33.8' E

Oman
2003 February 6
Lunar meteorite (VLT basalt-bearing feldspathic impact melt breccia)

A grey stone weighing 49 g was found in the Dhofar region of Oman. Mineralogy and classification (S. Demidova, M. Nazarov, Vernad., G. Kurat, NHMV): fusion crust is absent. The meteorite is an impact melt breccia; abundant mineral fragments and lithic clasts are set within a fine-grained impact melt matrix; the lithic clast population is dominated by impact melt breccias and granulitic rocks of anorthositic, troctolitic, noritic, and gabbronoritic compositions; the presence of VLT mare basalt clasts and rare KREEPy and granitic fragments is a characteristic feature of this meteorite; glass veins and fragments are common; feldspar, An_2-98Or_0-85; orthopyroxene, Wo_2-5En_49-90; clinopyroxene; Wo_5-47En_0.1-79, olivine, Fo_0.5-93 (Fe/Mn ~ 87 at); accessory minerals are ulvöspinel, Ti-rich chromite, pleonaste, ilmenite (0.4-7.4 wt % MgO), silica, troilite, and abundant FeNi metal (0.6-24 wt% Ni; 0.1-1.5 wt% Co); K-Ba feldspar, whitlockite, Cl-apatite, baddeleyite, zircon, Zr-armalcolite, monazite, tranquillityite, and zirconolite occur in granitic clasts. One fragment of tschermakitic amphibole was found. The stone is moderately weathered; calcite, gypsum, celestite, barite, smectite and Fe hydroxides are present. The meteorite was found close to Dho 489 but the stones are very different in composition. Dho 489 does not contain any mare basalt material. Specimens: type specimens of 10.1 g, and 2 thin sections, Vernad.; main mass with anonymous finder.

from The Meteoritical Bulletin, no. 89, Meteoritics & Planetary Science 40, A201-A263 (2005)

Dhofar 960

19°23.8' N, 54°33.5' E
Oman
Found 2003 November 16

Lunar meteorite (feldspathic impact melt breccia)

A grey stone weighing 35.4 g was found in the Dhofar region of Oman. Mineralogy and classification (S. Demidova, Vernad., F. Brandstätter, NHMV): Fusion crust is absent. The meteorite is an impact melt breccia with abundant mineral fragments and lithic clasts set within a fine-grained impact melt matrix. The lithic clasts are impact melt breccias and granulitic rocks of anorthositic, gabbro-noritic, troctolitic, and noritic compositions. A presence of VLT mare basalt clasts, KREEPy and rare granitic fragments is a characteristic feature of the meteorite. Glass veins and fragments are common. Mineral compositions are as follows; plagioclase, An_57-98Or_0-6; orthopyroxene, Wo₃-₅En_66-78; clinopyroxene; Wo_5-43En_0.4-73; olivine, Fo_4-90 (Fe/Mn ~= 92 at); accessory minerals are ulvöspinel, Cr-rich ulvöspinel, Ti-rich chromite, Al-rich chromite, pleonaste, ilmenite (0.7-7.4 wt.% MgO), silica, troilite, FeNi metal (5-21 wt.% Ni; 0.3-0.7 wt.% Co); K-Ba feldspar, pyroxferroite, whitlockite, apatite, baddeleyite, Zr-armalcolite and Zr-rich phases. The stone is moderately weathered; calcite, gypsum, celestite, smectite and Fe hydroxides are present. The meteorite was found close to Dho 925 and they are similar in texture, petrography and mineral chemistry. The stones may be paired. Specimens: type specimens of 7.4 g and 2 thin sections deposited at Vernad. The main mass is held by an anonymous finder.

from The Meteoritical Bulletin, no. 89, Meteoritics & Planetary Science 40, A201-A263 (2005)

Dhofar 961

19°23.9' N, 54°33.8' E
Oman
Found 2003 November 12

Lunar meteorite (feldspathic impact melt breccia)

A grey stone weighing 21.6 g was found nearby to the Dho 925 and 960 lunar meteorites in the Dhofar region of Oman. Mineralogy and classification (S. Demidova, Vernad, F. Brandstätter, NHMV): the meteorite is similar to Dho 925 and 960 in texture, mineralogy and mineral chemistry and the stones may be paired. Specimens: type specimens of 4.8 g and a thin section on deposit at Vernad. The main mass is held by an anonymous finder.

More Information

References

Demidova S. I., Nazarov M. A., Kurat G., Brandstätter F., and Ntaflos T. (2005) New lunar meteorites from Oman: Dhofar 925, 960 and 961, In Lunar and Planetary Science 36, abstract no. 1607, Lunar and Planetary Institute, Houston.

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 crust. Petrology 15 (4), 386-407.

Jolliff B. L., Zeigler R. A., Korotev R. L., and Carpenter P. K. (2007) Lunar meteorite Dhofar 961, mafic impact-melt breccia: Petrographic components and possible provenance (abstract). 70th Annual Meeting of the Meteoritical Society, abstract no. 5311. Lunar and Planetary Institute, Houston.

Jolliff B. L., Zeigler R. A., Korotev R. L., Carpenter P. K., Vicenzi E. P., and Davis J. M. (2008) Mafic impact-melt components in lunar meteorite Dhofar 961 (abstract). In Lunar and Planetary Science XXXIX, abstract no. 2519, 39th Lunar and Planetary Science Conference, Houston.

Jolliff B. L., Korotev R. L., Zeigler R. A., and Prettyman T. H. (2009) Connecting lunar meteorite Dhofar 961 to the South Pole-Aitken Basin through Lunar Prospector gamma-ray data (abstract). In Lunar and Planetary Science XL, abstract no. 2555, 40th Lunar and Planetary Science Conference, Houston.

Korotev R. L. (2005) Lunar geochemistry as told by lunar meteorites. Chemie der Erde 65, 297–346.

Korotev R. L. (2006) New geochemical data for a some poorly characterized lunar meteorites (abstract). In Lunar and Planetary Science XXVII, number 1404, Lunar and Planetary Institute, Houston.

Korotev R. L. and Zeigler R. A. (2007) Keeping up with the lunar meteorites (abstract). In Lunar and Planetary Science XXXVIII, abstract no. 1340, Lunar and Planetary Institute, Houston.

Korotev R. L., Zeigler R. A., and Jolliff B. L. (2007) Do we have a meteorite from the South Pole-Aitken basin of the Moon? (abstract). 70th Annual Meeting of the Meteoritical Society, abstract no. 5257. Lunar and Planetary Institute, Houston.

Korotev R. L., Zeigler R. A., Irving A. J., and Bunch T. E. (2009) Keeping up with the Lunar Meteorites — 2009 (abstract). In Lunar and Planetary Science XL, abstract no. 1137, 40th Lunar and Planetary Science Conference, Houston.

Korotev R. L, Zeigler R. A., Jolliff B. L., Irving A. J., and Bunch T. E. (2009) Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron composition. Meteoritics & Planetary Science 44, 1287–1322.

Chemical Classification

Overview | Dhofar 925 et al.

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Prepared by:

Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you’ve found until you read this and this.

e-mail: korotev@wustl.edu

Last revised: 03-Nov-2009