Accurately constraining the formation and evolution of the lunar magnesian suite is key to understanding the earliest periods of magmatic crustal building that followed accretion and primordial differentiation of the Moon. However, the origin and evolution of these unique rocks is highly debated. Here, we report on the microstructural characterization of a large (~250-μm) baddeleyite (monoclinic-ZrO2) grain in Apollo troctolite 76535 that preserves quantifiable crystallographic relationships indicative of reversion from a precursor cubic-ZrO2 phase. This observation places important constraints on the formation temperature of the grain (>2,300 °C), which endogenic processes alone fail to reconcile. We conclude that the troctolite crystallized directly from a large, differentiated impact melt sheet 4,328 ± 8 Myr ago. These results suggest that impact bombardment would have played a critical role in the evolution of the earliest planetary crusts.
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The authors declare that data supporting the findings in this study are available within the paper and its Supplementary Information files. All other data are available from the corresponding author upon request.
The code that was used for the U–Pb analysis is available from the corresponding author upon request.
Timms, N. E. et al. Cubic zirconia in >2370 °C impact melt records Earth’s hottest crust. Earth Planet. Sci. Lett. 477, 52–58 (2017).
Cayron, C., Douillard, T., Sibil, A., Fantozzi, G. & Sao-Jao, S. Reconstruction of the cubic and tetragonal parent grains from electron backscatter diffraction maps of monoclinic zirconia. J. Am. Ceram. Soc. 93, 2541–2544 (2010).
Sylvester, P., Crowley, J. & Schmitz, M. U–Pb zircon age of Mistastin Lake crater, Labrador, Canada—implications for high-precision dating of small impact melt sheets and the end Eocene extinction. Mineral. Mag. 77, 2295 (2013).
White, L. F. et al. Baddeleyite as a widespread and sensitive indicator of meteorite bombardment in planetary crusts. Geology 46, 719–722 (2018).
Hinthorne, J. R., Conrad, R. & Andersen, C. A. Lead–lead age and trace element abundances in lunar troctolite 76535. In Proc. Lunar and Planetary Science Conference Vol. 6, 373–375 (Lunar and Planetary Institute, 1975).
Elrado, S. M., McCubbin, F. M. & Shearer, C. K. Jr. Chromite symplectites in Mg-suite troctolite 76535 as evidence for infiltration metasomatism of a lunar layered intrusion. Geochim. Cosmochim. Acta 87, 154–177 (2012).
Borg, L. E., Connelly, J. N., Cassata, W. S., Gaffney, A. M. & Bizzarro, M. Chronological implications for slow cooling of troctolite 76535 and temporal relationships between the Mg-suite and the ferroan anorthosite suite. Geochim. Cosmochim. Acta 201, 377–391 (2017).
Gooley, R., Brett, R., Warner, J. & Smyth, J. A lunar rock of deep crustal origin: sample 76535. Geochim. Cosmochim. Acta 38, 1329–1339 (1974).
Garrick-Bethell, I. et al. Troctolite 76535: a sample of the Moon’s South Pole–Aitken basin? Icarus 338, 113430 (2020).
Rubin, A. E. Maskelynite in asteroidal, lunar and planetary basaltic meteorites: an indicator of shock pressure during impact ejection from their parent bodies. Icarus 257, 221–229 (2015).
Warren, P. H. A concise compilation of petrologic information on possibly pristine nonmare Moon rocks. Am. Mineral. 78, 360–376 (1993).
Day, J. M. D., Walker, R. J., James, O. B. & Puchtel, I. S. Osmium isotope and highly siderophile element systematics of the lunar crust. Earth Planet. Sci. Lett. 289, 595–605 (2010).
Elrado, S. M., Draper, D. S. & Shearer, C. K. Jr. Lunar Magma Ocean crystallization revisited: bulk composition, early cumulate mineralogy, and the source regions of the highlands Mg-suite. Geochim. Cosmochim. Acta 75, 3024–3045 (2011).
Shearer, C. K., Elrado, S. M., Petro, N. E., Borg, L. E. & McCubbin, F. M. Origin of the lunar highlands Mg-suite: an integrated petrology, geochemistry, chronology, and remote sensing perspective. Am. Mineral. 100, 294–325 (2015).
Taylor, S. R., Norman, M. D. & Esat, T. M. The Mg-suite and the highland crust: an unsolved enigma. In Proc. Lunar and Planetary Science Conference Vol. 24, 1413–1414 (Lunar and Planetary Institute, 1993).
Garrick-Bethell, I., Weiss, B. P., Shuster, D. L., Tikoo, S. M. & Tremblay, M. M. Further evidence for early lunar magnetism from troctolite 76535. J. Geophys. Res. Planets 121, 76–93 (2016).
Timms, N. E. et al. A pressure-temperature phase diagram for zircon at extreme conditions. Earth-Sci. Rev. 165, 185–202 (2017).
Cayron, C. ARPGE: a computer program to automatically reconstruct the parent grains from electron backscatter diffraction data. J. Appl. Crystallogr. 40, 1183–1188 (2007).
Swab, J. Role of Oxide Additives in Stabilizing Zirconia for Coating Applications (Army Research Laboratory, 2001).
Zhang, N., Parmentier, E. M. & Liang, Y. A 3-D numerical study of the thermal evolution of the Moon after cumulate mantle overturn: the importance of rheology and core solidification. J. Geophys. Res. Planets 118, 1789–1804 (2013).
Hurwitz, D. M. & Kring, D. A. Differentiation of the South Pole–Aitken basin impact melt sheet: implications for lunar exploration. J. Geophys. Res. Planets 119, 1110–1133 (2014).
Latypov, R., Chistyakova, S., Grieve, R. & Huhma, H. Evidence for igneous differentiation in Sudbury Igneous Complex and impact-driven evolution. Nat. Commun. 10, 508 (2019).
Canup, R. M. & Asphaug, E. Origin of the Moon in a giant impact near the end of the Earth’s formation. Nature 412, 708–712 (2001).
Jacobson, S. A. et al. Highly siderophile elements in the Earth’s mantle as a clock for the moon-forming impact. Nature 508, 84–87 (2014).
Herd, C. D. K. et al. in Microstructural Geochronology: Planetary Records Down to Atom Scale (eds Moser et al.) 137–165 (American Geophysical Union, 2018).
White, L. F. et al. Atomic-scale age resolution of planetary events. Nat. Commun. 8, 15597 (2017).
Darling, J. R. et al. Variable microstructural response of baddeleyite to shock metamorphism in young basaltic shergottite NWA 5298 and improved U–Pb dating of Solar System events. Earth Planet. Sci. Lett. 444, 1–12 (2016).
Crow, C. A., McKeegan, K. D. & Moser, D. E. Coordinated U–Pb geochronology, trace element, Ti-in-zircon thermometry and microstructural analysis of Apollo zircons. Geochim. Cosmochim. Acta 202, 264–284 (2017).
Borg, L. E., Connelly, J. N., Boyet, M. & Carlson, R. W. Chronological evidence that the Moon is either young or did not have a global magma ocean. Nature 477, 70–72 (2011).
Nemchin, A. et al. Timing of crystallization of the lunar magma ocean constrained by the oldest zircon. Nat. Geosci. 2, 133–136 (2009).
Petrus, J. A., Ames, D. E. & Kamber, B. S. On the track of the elusive Sudbury impact: geochemical evidence for a chondrite or comet bolide. Terra Nova 27, 9–20 (2015).
Borg, L. E., Gaffney, A. M. & Shearer, C. K. A review of lunar chronology revealing a preponderance of 4.34-4.37 Ga ages. Meteorit. Planet. Sci. 50, 715–732 (2015).
Hess, P. C. The petrogenesis of lunar troctolites. J. Geophys. Res. 99, 19083–19093 (1994).
O’Connell-Cooper, C. D. & Spray, J. G. Geochemistry of the impact-generated melt sheet at Manicouagan: evidence for fractional crystallization. J. Geophys. Res. Solid Earth 116, B06204 (2011).
Darling, K. R., Hawkesworth, C. J., Storey, C. D. & Lightfoot, P. C. Shallow impact: isotopic insights into crustal contributions to the Sudbury impact melt sheet. Geochim. Cosmochim. Acta 74, 5680–5696 (2010).
Snape, J. F. et al. Ancient volcanism on the Moon: insights from Pb isotopes in the MIL 13317 and Kalahari 009 lunar meteorites. Earth Planet. Sci. Lett. 502, 84–95 (2018).
Elkins-Tanton, L. T., Hager, B. H. & Grove, T. L. Magmatic effects of the lunar late heavy bombardment. Earth Planet. Sci. Lett. 222, 17–27 (2004).
Smith, D. K. & Newkirk, W. The crystal structure of baddeleyite (monoclinic ZrO2) and its relation to the polymorphism of ZrO2. Acta Crystallogr. 18, 983–991 (1965).
Cayron, C. GenOVa: a computer program to generate orientational variations. J. Appl. Crystallogr. 40, 1179–1182 (2007).
Whitehouse, M. J., Kamber, D. S., Fedo, C. M. & Lepland, A. The importance of combined Pb and S isotope data from early Archaean rocks, southwest Greenland, for the interpretation of S-isotope signatures. Chem. Geol. 222, 112–131 (2005).
Reischmann, T. Precise U/Pb age determination with baddeleyite (ZrO2), a case study from the Phalaborwa igneous complex, South Africa. S. Afr. J. Geol. 98, 1–4 (1995).
Steiger, R. H. & Jäger, E. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth Planet. Sci. Lett. 36, 359–362 (1977).
Park, J. et al. Newly determined Ar/Ar ages of lunar troctolite 76535. In Proc. Lunar and Planetary Science Conference Vol. 46, 2018 (Lunar and Planetary Institute, 2015).
Heaman, L. M. & LeCheminant, A. N. Paragenesis and U–Pb systematics of baddeleyite (ZrO2). Chem. Geol. 110, 95–126 (1993).
Marchi, S. et al. High-velocity collisions from the lunar cataclysm recorded in asteroidal meteorites. Nat. Geosci. 6, 303–307 (2013).
Hiesinger, H. et al. New crater counts of the South Pole–Aitken basin. In EGU General Assembly 8410 (European Geosciences Union, 2012).
L.F.W. and A.C. are funded by a Hatch postdoctoral fellowship. A.C. has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 704696 RESOLVE, and M.A.’s contribution to this work was partly funded by the UK Science and Technology Facilities Council (ST/L000776/1 and ST/P000657/1). The NordSIMS facility is supported by Swedish Research Council infrastructure grant 2017-00671 and the Swedish Museum of Natural History; this is NordSIMS publication 609. K.H.J. acknowledges STFC grant ST/M001253 and Royal Society grant UF140190. J.R.D. acknowledges STFC grant ST/S000291/1 and Royal Society Research Grant RG160237. We thank G. Long for conducting colloidal silica polishing of the thin section to facilitate EBSD analysis of the target grain. M.A. thanks NASA CAPTEM for the allocation of polished thin section 76535, 51.
The authors declare no competing interests.
Peer review information Nature Astronomy thanks Marc Norman and Jennifer Whitten for their contribution to the peer review of this work.
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White, L.F., Černok, A., Darling, J.R. et al. Evidence of extensive lunar crust formation in impact melt sheets 4,330 Myr ago. Nat Astron (2020). https://doi.org/10.1038/s41550-020-1092-5
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