Abstract
Fragments of aluminous enstatite from lunar meteorites of highland origin were investigated. It was found that such fragments usually occur in impact breccias of troctolitic composition. The aluminous enstatite contains up to 12 wt % Al2O3 and shows low CaO (<1 wt %) and almost constant high Mg/(Mg + Fe) ratio (89.5 ± 1.4 at %) identical to that of the Earth’s mantle. With respect to these parameters, the aluminous enstatites are distinctly different from common orthopyroxene of lunar rocks. The aluminous enstatite associates with spinel (pleonaste), olivine, anorthite (clinopyroxene was never found), and accessory minerals: rutile, Ti-Zr oxides, troilite, and Fe-Ni metal. The same assemblage was described in rare fragments of spinel cataclasites from the samples of the Apollo missions. Thermobarometry and the analysis of phase equilibria showed that the rocks hosting aluminous enstatite are of deep origin and occurred at depths from 25 km to 130–200 km at T from 800 to 1300°C, i.e., at least in the lower crust and, possibly, in the upper mantle of the Moon. These rocks could form individual plutons or dominate the composition of the lower crust. The most probable source of aluminous enstatite is troctolitic magnesian rocks and, especially, spinel troctolites with low Ca/Al and Ca/Si ratios. The decompression of such rocks must produce cordierite-bearing assemblages. The almost complete absence of such assemblages in the surficial rocks of lunar highlands implies that vertical tectonic movements were practically absent in the lunar crust. The transport of deep-seated materials to the lunar surface was probably related to impact events during the intense meteorite bombardments >3.9 Ga ago.
Similar content being viewed by others
References
Anderson, A.T., The Texture and Mineralogy of Lunar Peridotite, 15445.10, J. Geol., 1973, vol. 81, pp. 219–226.
Baker, M.B. and Herzberg, C.T., Spinel Cataclasites in 15445 and 72435: Petrology and Criteria for Equilibrium, Proc. 11th Lunar Planet. Sci. Conf. 1980, pp. 535–553.
Bence, A.E., Delano, J.W., Papike, J.J., and Cameron, K.L., Petrology of the Highlands Massif at Taurus-Littrow: An Analysis of the 2–4 Mm Soil Fraction, Proc. 5th Lunar Sci. Conf, 1974, pp. 785–827.
Berman, R.G. and Aranovich, L.Y., Optimized Standard State and Solution Properties of Minerals: I. Model Calibration for Olivine, Orthopyroxene, Cordierite, Garnet, and Ilmenite in the System FeO-MgO-CaO-Al2O3-TiO2-SiO2, Contrib. Mineral. Petrol., 1996, vol. 126, pp. 1–22.
Berman, R.G., Thermobarometry Using Multi-Equilibrium Calculations — a New Technique, with Petrological Applications, Can. Mineral., 1991, vol. 29, pp. 833–855.
de Capitani, C., Gleichgewichts-Phasendiagramme: Theorie Und Software. Berichte Der Deutschen Mineralogischen Gesellschaft, Beiheft Zum, Eur. J. Mineral, 1994, vol. 6, p. 48.
Demidova, S., Nazarov, M., Taylor, L., and Patchen, A., Dhofar 304, 305, 306 and 307: New Lunar Highland Meteorites from Oman, Proc. 34th Conf. Lunar Planet. Sci., 2003b, #1285.pdf.
Demidova, S.I., Nazarov, M.A., Kurat, G., et al., Lunar Meteorite Dhofar 310: A Polymict Breccia with Deep-Seated Lunar Crustal Material, Meteorit. Planet. Sci., 2003a, vol. 38, p. A30.
Demidova, S.I., Nazarov, M.A., Lorents, K.A., et al., Chemical Composition of Lunar Meteorites and the Lunar Crust, Petrologiya, 2007, vol. 16, no. 4, pp. 416–437 [Petrology (Engl. Transl.), vol. 15, no. 4, pp. 386–407].
Dymek, R.F., Albee, A.L., and Chodos, A.A., Petrology and Origin of Boulders #2 and #3, Apollo 17 Station 2, Proc. 7th Lunar Sci. Conf., 1976, pp. 2335–2378.
Gasparik, T., An Internally Consistent Thermodynamic Model for the System CaO-MgO-Al2O3-SiO2 Derived Primarily from Phase Equilibrium Data, J. Geol., 2000, vol. 108, pp. 103–119.
Gooley, R., Brett, R., Warner, J., and Smyth, J.R., A Lunar Rock of Deep Crustal Origin: Sample 76535, Geochim. Cosmochim. Acta, 1974, vol. 38, pp. 1329–1339.
Gros, J., Takahashi, H., Hertogen, J., et al., Composition of the Projectiles That Bombarded the Lunar Highlands, Proc. 7th Lunar Sci. Conf., 1976, pp. 2403–2425.
Hammond, N.P., Nimmo, F., and Korycansky, D., Hydrocode Modeling of the South Pole Aitken Basin-Forming Impact, Proc. 40th Lunar Planet. Sci. Conf., 2009, #1455.pdf.
Herzberg, C.T. and Baker, M.B., The Cordierite-To Spinel-Cataclasite Transition: Structure of the Lunar Crust, Proc. Conf. on the Lunar Highland Crust, 1980, pp. 113–132.
Herzberg, C.T., The Bearing of Spinel Cataclasites on the Crust-Mantle Structure of the Moon, Proc. 9th Lunar Sci. Conf., 1978, pp. 319–336.
Kosyakova, N.A., Aranovich, L.Ya., and Podlesskii, K.K., Equilibria of Aluminous Spinel with Orthopyroxene in the System FeO-MgO-Al2O3-SiO2: New Experimental Data and Thermodynamic Assessment, Dokl. Akad. Nauk, 2005, vol. 400, no. 1, pp. 78–82 [Dokl. Earth Sci. (Engl. Transl.), vol. 400, no. 1, pp. 57–61].
Kuskov, O.L. and Kronrod, V.A., The Moon: Chemical Composition and Internal Structure, Astron. Vestn., 1999, vol. 33, no. 5, pp. 437–446 [Solar Syst. Res., vol. 33, pp. 382–391].
Liermann, H.P. and Ganguly, J., Fe2+-Mg Fractionation between Orthopyroxene and Spinel: Experimental Calibration in the System FeO-MgO-Al2O3-Cr2O3-SiO2, and Applications, Contrib. Mineral. Petrol., 2003, vol. 145, pp. 217–227.
Ma, M.-S., Schmitt, R.A., Taylor, G.J., et al., Chemical and Petrographic Study of Spinel Troctolite in 67435: Iimplications for the Origin of Mg-Rich Plutonic Rocks, Proc. 12th Lunar Planet. Sci. Conf., 1981, pp. 640–642.
Marvin, U.B., Carey, J.W., and Lindstrom, M.M., Cordierite-Spinel Troctolite, a New Magnesium-Rich Lithology from the Lunar Highlands, Science, 1989, vol. 243, pp. 925–928.
McCallum, I.S. and Schwartz, J.M., Lunar Mg Suite: Thermobarometry and Petrogenesis of Parental Magmas, J. Geophys. Res., 2001, vol. 106, no. E11, pp. 27969–27983.
Mercier, J-C.C. and Nicolas, A., Textures and Fabrics of Upper-Mantle Peridotites As Illustrated by Xenoliths from Basalts, J. Petrol., 1975, vol. 16, no. 2, pp. 454–487.
Mercier, J-C.C., Single-Pyroxene Geothermometry and Geobarometry, Am. Mineral., 1976, vol. 61, pp. 603–615.
Nazarov, M., Demidova, S., and Taylor, L., Trace Element Chemistry of Lunar Highland Meteorites from Oman, Proc. 34th Lunar Planet. Sci. Conf., 2003, #1636.pdf.
Nazarov, M., Demidova, S.I., Patchen, A., and Taylor, L.A., Dhofar 311, 730 and 731: New Lunar Meteorites from Oman, Proc. 33rd Lunar Planet. Sci. Conf., 2002, #1293.pdf.
Nazarov, M.A., Badyukov, D.D., Lorents, K.A., and Demidova, S.I., The Flux of Lunar Meteorites onto the Earth, Astron. Vestn., 2003, vol. 37, no. 6, pp. 1–10 [Solar. Syst. Res., vol. 38, pp. 49–58].
Nazarov, M.A., Demidova, S.I., Brandstaetter, F., et al., Deep-Seated Crustal Material in Dhofar Lunar Meteorites: Evidence from Pyroxene Chemistry, Proc. 36th Lunar Planet. Sci., 2005, #1063.pdf.
Nazarov, M.A., Demidova, S.I., Patchen, A., and Taylor, L.A., Dhofar 311, 730 and 731: Three New Lunar Highland Meteorites from Oman, Proc. 35th Lunar. Planet. Sci. Conf., 2004, #1233.pdf.
Nazarov, M.A., Ntaflos, Th., Brandstaetter, F., and Kurat, G., FeO/MnO Ratios of Lunar Meteorite Minerals, Proc. 40th Lunar Planet. Sci. Conf., 2009, #1059.pdf.
Pieters, C.M., Boardman, J., Burratti, B., et al., Identificationb of a New Spinel-Rich Lunar Rock Type by the Moon Mineralogy Mapper (M3), Proc. 41st Lunar Planet. Sci. Conf., 2010, #1854. pdf.
Ridley, W.I., Hubbard, N.J., Rhodes, J.M., et al., The Petrology of Lunar Breccia 15445 and Petrogenetic Implications, J. Geol., 1973, vol. 81, pp. 621–631.
Taylor, S.R., Planetary Science: A Lunar Perspective, Houston, Texas: Lunar and Planetary Institute, 1982.
Taylor, S.R., Taylor, G.J., and Taylor, L.A., The Moon: A Taylor Perspective, Geochim. Cosmochim. Acta, 2006, vol. 70, pp. 5904–5918.
Toksöz, M.N. and Johnston, D.H., The Evolution of the Moon and the Terrestrial Planets, Soviet-American Conf. “Cosmochemistry of the Moon and Planets”, 1977, pp. 295–328.
Walker, D., Grove, T.L., Longhi, J., et al., Origin of Lunar Feldspathic Rocks, Earth Planet. Sci. Lett., 1973, vol. 20, pp. 325–336.
Warner, R.D., Taylor, G.J., Mansker, W.L., and Keil, K., Clast Assemblages of Possible Deep-Seated (77517) and Immiscible-Melt (77538) Origins in Apollo 17 Breccias, Proc. 9th Lunar Planet. Sci. Conf., 1978, pp. 941–958.
Warren, P.H., “New” Lunar Meteorites: Implications for Composition of the Global Lunar Surface, Lunar Crust, and the Bulk Moon, Meteorit. Planet. Sci., 2005, vol. 40, pp. 477–506.
Wieczorek, M.A., Jolliff, B.L., Khan, A., et al., The Constitution and Structure of the Lunar Interior, Rev. Mineral. Geochemi, 2006, vol. 60, pp. 221–364.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © M.A. Nazarov, L.Ya. Aranovich, S.I. Demidova, T. Ntaflos, F. Brandstätter, 2011, published in Petrologiya, 2011, vol. 19, No. 1, pp. 14–26.
Rights and permissions
About this article
Cite this article
Nazarov, M.A., Aranovich, L.Y., Demidova, S.I. et al. Aluminous enstatites of lunar meteorites and deep-seated lunar rocks. Petrology 19, 13–25 (2011). https://doi.org/10.1134/S0869591111010061
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0869591111010061