Mount DeWitt 12007 (DEW 12007)
Transantarctic Mountains, Antarctica
History: A single unweathered stone was found on a blue ice patch during the XXVIII PNRA expedition, 2012-2013 (in collaboration with KOREAMET). Nine additional distinct meteorites were found in the same icefield.
Physical characteristics: Fresh, oblate (7 × 3 × 3 cm) stone of 94.2 g. 7% of the external surface is covered by a dark brown vesicular fusion crust. The remaining surface shows abundant mm-sized white and pale gray clasts embedded in a dark gray fine-grained matrix.
Petrography: (A. Collareta and L. Folco, DST-PI) Breccia consisting of numerous crystal fragments (pyroxene, plagioclase, olivine, silica polymorphs), plagioclase-rich clasts, gabbroic clasts, impact melt particles, rare basaltic and mingled breccia clasts. Clasts are embedded in a very fine crystal-rich matrix, which contains vesicular glassy veins and agglutinates. Main minerals are plagioclase, pyroxene (pigeonite and augite), olivine, Ti-bearing chromite, Cr-bearing ulvöspinel, ilmenite, troilite, minor silica polymorphs, baddeleyite, tranquillityite, and tiny FeNi-metal grains.
Geochemistry: (M. Gemelli, M. D’Orazio, A. Collareta, DST-PI) Pigeonite Fs42.3±10.7Wo13.5±3.5, Fe/Mn=63±11, n=19; augite Fs41.1±12.3Wo28.8±4.6, Fe/Mn=66±9, n=14, plagioclase An92.1±3.6Ab7.6±3.5Or0.3±0.1, n=13, fayalitic olivine Fa90.6±2.0, Fe/Mn=90±2, n=4, forsteritic olivine Fa41.5±6.0, Fe/Mn=94±2, n=3. All analyses by EPMA. Bulk Fe/Mn = 65 by HHXRF. Oxygen isotopes done by laser fluorination (A. Pack, UGött): d18O = 6.05, d17O = 3.13, Δ17O = -0.071 (all permil).
Classification: Lunar (mingled regolithic breccia)
Specimens: 47.5 g endcut (type specimen) at MNA-SI, 46.7 g endcut at KOPRI.
Mount DeWitt (DEW) 12007 is almost certainly launch paired with to QUE 94281 and Yamato 793274/981031 from Antarctica as well as NWA 4884 and the NWA 7611 clan from the Sahara and possibly EET 87521/96008 from Antarctica. See discussion at NWA 7611.
Meteoritical Bulletin Database
Choi J., Nagao K., Park J., Baek J. M., Lee J. I., Ebel D. S., and Weisberg M. K. (2019) In-situ noble gas analysis of Mount Dewitt 12007 lunar meteorite. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6281.
Collareta A., D’Orazio M., Gemelli M., Pack A., Folco L. (2014) The new lunar meteorite DEW 12007. 77th Annual Meeting of the Meteoritical Society, abstract no. 5104.
Collareta A., D’Orazio M., Gemelli M., Pack A., Folco L. (2016) High crustal diversity preserved in the lunar meteorite Mount DeWitt 12007 (Victoria Land, Antarctica). Meteoritics & Planetary Science 51, 351-371.
Korotev R. L. and Irving A. J. (2016) Not quite keeping up with the lunar meteorites – 2016. 47th Lunar and Planetary Science Conference, abstract no. 1358.
Nishiizumi K., Caffee M. W., and Jull A. J. T. (2016) Exposure history of Mount DeWitt 12007 and proposed launch-paired Northwest Africa 4884, 7611, and 8277 lunar meteorites. 79th Annual Meeting of the Meteoritical Society, abstract no. 6514.
Will P., Busemann H., Riebe M. E. I., and Maden C. (2019) Regolith history of six lunar regolith breccias derived from noble gas elemental and isotopic abundances. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6494.