Lunar Meteorite: Dominion Range 18262 and pairs

Dominion Range, Transantarctic Mountains, Antarctica

The Dominion Range 18262 clan consists of 18242, 18244, 18262, 18509, 18543, 18666, & 18678

The 7 Dominion Range 18xxx stones. Photo credit: NASA/JSC

from The Meteoritical Bulletin, No. 108

Dominion Range (DOM) 18262, 18509, 18543, 18666, & 18678

Dominion Range, Antarctica
Found: 2018
Mass: 6.777g, 16.52 g, 13.59 g, 45.87 g, and 11.64 g (total: 94.40, 1 piece each)

Classification: lunar basaltic breccia

Mineral Composition: Fayalite (mol%): 71-95; Ferrosilite (mol%): 29-79

Weathering: A/B

Fracturing: A

Macroscopic Description – Cecilia Satterwhite (NASA-JSC). The exterior has black patches of fusion crust on a brown rusty exterior with some white specks visible. The fine grained black matrix has abundant white/tan inclusions with minor oxidation.

Thin Section Description (,2) – Cari Corrigan, Tim McCoy (National Museum of Natural History, Smithsonian Institution) These sections are similar enough that one description will suffice. These sections consist of a highly brecciated assemblage of mostly single mineral grains ranging up to 0.5 mm in size. Grains are dominated by pyroxene and plagioclase with rare large olivine fragments. Polymineralic igneous fragments/clasts include coarse grained gabbro and symplectites. Melt veins and pockets were observed in all sections. DOM 18262 contains a fine grained apparently anorthositic fragment (~2 mm in max dimension) and a few melt droplets (approx. 100 microns in diameter) were observed. Olivines are fayalitic (Fa90-99), although two grains of Fa56 and Fa71 were analyzed. Pyroxene is dominantly pigeonite with fine exsolution, with orthopyroxene of Fs27Wo3 and augite Fs50Wo40. Rare high-FeO pigeonite (up to Fs80) is observed associated with the symplectite. Fe/Mn of pyroxenes ranges from ~50-70. Plagioclase is calcic with An90-97Or0.1-0.7. These meteorites are lunar basaltic breccias, likely regolith breccias.

from The Meteoritical Bulletin, No. 109

Dominion Range (DOM) 18242

Dominion Range, Antarctica
Found: 2018
Mass: 15.12 g (1 piece)

Classification: lunar basaltic breccia

Mineral Composition: Ferrosilite (mol%): 31-52

Weathering: A/B

Fracturing: B

Macroscopic Description – Kellye Pando. Exterior is dark grey brown with some fracturing and small (0.5-1mm) white inclusions. There are also some light grey-brown inclusions that are up to 3mm in size. Fresh interior is grey matrix with inclusions that are white, light brown or grey and up to 3mm in size.

Thin Section Description (,2) – Cari Corrigan, Tim McCoy (National Museum of Natural History, Smithsonian Institution) These sections are similar enough that one description will suffice. They consist of a highly brecciated assemblage of mostly single mineral grains ranging up to 0.5 mm in size. Grains are dominated by pyroxene and plagioclase (no olivine grains were analyzed in these sections). Polymineralic igneous fragments/clasts include coarse grained gabbro and symplectites. Melt veins and pockets were observed in both sections. Pyroxene is dominantly pigeonite with fine exsolution, with orthopyroxene of Fs30Wo3 and augite Fs20-64Wo20-39. Fe/Mn of pyroxenes ranges from ~50-70. Plagioclase is calcic with An91-99Or0.1-0.3. These meteorites are lunar basaltic breccias, likely regolith breccias and are most certainly paired with DOM 18262 pairing group reported in the Fall 2019 newsletter.

from The Meteoritical Bulletin, No. 109

Dominion Range (DOM) 18244

Dominion Range, Antarctica
Found: 2018
Mass: 25.07 g (1 piece)

Classification: lunar basaltic breccia

Mineral Composition: Ferrosilite (mol%): 20-64

Weathering: A/B

Fracturing: A

Macroscopic Description – Curtis Calva. Exterior has a dark brown fusion crust that is rough with light spots less than 1 mm. Approximately 40% fusion crust on the exterior and it is slightly fractured. Exposed interior is dark gray to black with light colored inclusions. The interior is dark gray to black with light brown and white inclusions that are less than 2 mm.

Thin Section Description (,2) – Cari Corrigan, Tim McCoy (National Museum of Natural History, Smithsonian Institution) These sections are similar enough that one description will suffice. They consist of a highly brecciated assemblage of mostly single mineral grains ranging up to 0.5 mm in size. Grains are dominated by pyroxene and plagioclase (no olivine grains were analyzed in these sections). Polymineralic igneous fragments/clasts include coarse grained gabbro and symplectites. Melt veins and pockets were observed in both sections. Pyroxene is dominantly pigeonite with fine exsolution, with orthopyroxene of Fs30Wo3 and augite Fs20-64Wo20-39. Fe/Mn of pyroxenes ranges from ~50-70. Plagioclase is calcic with An91-99Or0.1-0.3. These meteorites are lunar basaltic breccias, likely regolith breccias and are most certainly paired with DOM 18262 pairing group reported in the Fall 2019 newsletter.

Randy Says…

I have not studied this one. Several people are working on it.

More Information

Meteoritical Bulletin Database

DOM 18242 | 18244 |18262 | 18509 | 18543 | 18666 | 18678

Map

ANSMET Location Map

References

Gross J., Eckley S., Zeigler R.A., and Vander Kaaden K. E. (2020) Treasure trove Antarctica: Petrology, geochemistry and pairing of lunar meteorites Dominion Range (DOM) 18509, 18543, and 18678. 51st Lunar and Planetary Science Conference, abstract no. 2555.

Hayden T. S., Barrett T. J., Zhao X., Degli-Alessandrini G., Anand M., Franchi I. A. (2021) Chlorine and hydrogen in brecciated lunar meteorites: Implications for lunar volatile history. 52nd Lunar and Planetary Science Conference, abstract no. 1550.

McLeod C. L., Shaulis B., Brum J. T., and Gawronska A. J., 1 (2020) More meteorites, more insights! Five new lunar basaltic meteorites from the Dominion Range. 51st Lunar and Planetary Science Conference, abstract no. 2634.

 

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