The Moon’s Earth-facing hemisphere hosts a geochemically anomalous region, the Procellarum KREEP Terrane, which is widely thought to have provided radiogenic heat for mantle melting from ~3.9 to ~1 billion years ago. However, there is no agreement on such a link between this region and the earliest pulse of post-differentiation crust-building magmatism on the Moon at ~4.37 billion years ago; whether this early magmatism was global or regional has been debated. Here we present results of high-temperature experiments that show the nearside geochemical anomaly may have caused asymmetric early crust building via mantle melting-point depression. Our results demonstrate that the anomalous enrichment in incompatible elements of this nearside reservoir dramatically lowers the melting temperature of the source rock for these magmas and may have resulted in 4 to 13 times more magma production under the nearside crust, even without any contribution from radioactivity. From thermal numerical modelling, we show that radiogenic heating compounds this effect and may have resulted in an asymmetric concentration of post-magma-ocean crust building on the lunar nearside. Our findings suggest that the nearside geochemical anomaly has influenced the thermal and magmatic evolution of the Moon over its entire post-differentiation history.
Subscribe to Journal
Get full journal access for 1 year
only $4.92 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data supporting the findings of this study are available within the article and its Supplementary Information files.
The code used for the thermal evolution calculations presented here is available from M.L. upon request. Email: email@example.com.
Elkins-Tanton, L. T. Magma oceans in the inner Solar System. Annu. Rev. Earth Planet. Sci. 40, 113–139 (2012).
Wasson, J. T. & Warren, P. H. Contribution of the mantle to the lunar asymmetry. Icarus 44, 752–771 (1980).
Loper, D. E. & Werner, C. L. On lunar asymmetries 1. Tilted convection and crustal asymmetry. J. Geophys. Res. Planets 107, 5046 (2002).
Ohtake, M. et al. Asymmetric crustal growth on the Moon indicated by primitive farside highland materials. Nat. Geosci. 5, 384–388 (2012).
Quillen, A. C., Martini, L. & Nakajima, M. Near/far side asymmetry in the tidally heated Moon. Icarus 329, 182–196 (2019).
Wieczorek, M. A. et al. The crust of the Moon as seen by GRAIL. Science 339, 671–675 (2013).
Zuber, M. T., Smith, D. E., Lemoine, F. G. & Neumann, G. A. The shape and internal structure of the Moon from the Clementine mission. Science 266, 1839–1843 (1994).
Jolliff, B. L., Gillis, J. J., Haskin, L. A., Korotev, R. L. & Wieczorek, M. A. Major lunar crustal terranes: surface expressions and crust–mantle origins. J. Geophys. Res. 105, 4197–4216 (2000).
Lawrence, D. J. et al. Global elemental maps of the Moon: the Lunar Prospector gamma-ray spectrometer. Science 281, 1484–1489 (1998).
Head, J. W. Lunar volcanism in space and time. Rev. Geophys. 14, 265–300 (1976).
Metzger, A., Haines, E., Parker, R. & Radocinski, R. Thorium concentrations in the lunar surface I: regional values and crustal content. In Proc. 8th Lunar Science Conference 949–999 (Pergamon, 1977).
Laneuville, M., Wieczorek, M. A., Breuer, D. & Tosi, N. Asymmetric thermal evolution of the Moon. J. Geophys. Res. Planets 118, 1435–1452 (2013).
Wieczorek, M. A. & Phillips, R. J. The “Procellarum KREEP Terrane”: implications for mare volcanism and lunar evolution. J. Geophys. Res. Planets 105, 20417–20430 (2000).
Hess, P. C. & Parmentier, E. M. Thermal evolution of a thicker KREEP liquid layer. J. Geophys. Res. Planets 106, 28023–28032 (2001).
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).
Carlson, R. W., Borg, L. E., Gaffney, A. M. & Boyet, M. Rb–Sr, Sm–Nd and Lu–Hf isotope systematics of the lunar Mg-suite: the age of the lunar crust and its relation to the time of Moon formation. Philos. Trans. R. Soc. A 372, 20130246 (2014).
Borg, L. E., Connelly, J. N., Cassata, W. S., Gaffney, A. M. & Bizzarro, M. Chronologic 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).
Gaffney, A. M. & Borg, L. E. A young solidification age for the lunar magma ocean. Geochim. Cosmochim. Acta 140, 227–240 (2014).
Shearer, C. K., Elardo, 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).
Elardo, S. M., Draper, D. S. & Shearer, C. K. 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).
Hess, P. C. Petrogenesis of lunar troctolites. J. Geophys. Res. Planets 99, 19083–19093 (1994).
Prissel, T. C., Parman, S. W. & Head, J. W. Formation of the lunar highlands Mg-suite as told by spinel. Am. Mineral. 101, 1624–1635 (2016).
Warren, P. H. The origin of pristine KREEP: effects of mixing between urKREEP and the magmas parental to the Mg-rich cumulates. In Proc. 18th Lunar and Planetary Science Conference 233–241 (Cambridge Univ. Press/Lunar and Planetary Institute, 1988).
Shearer, C. K. & Papike, J. J. Early crustal building processes on the Moon: models for the petrogenesis of the magnesian suite. Geochim. Cosmochim. Acta 69, 3445–3461 (2005).
Shervais, J. W. & McGee, J. J. Ion and electron microprobe study of troctolites, norite, and anorthosites from Apollo 14: evidence for urKREEP assimilation during petrogenesis of Apollo 14 Mg-suite rocks. Geochim. Cosmochim. Acta 62, 3009–3023 (1998).
Korotev, R. L. The great lunar hot spot and the composition and origin of the Apollo mafic (“LKFM”) impact-melt breccias. J. Geophys. Res. Planets 105, 4317–4345 (2000).
Pieters, C. M. et al. The distribution of Mg-spinel across the Moon and constraints on crustal origin. Am. Mineral. 99, 1893–1910 (2014).
Prissel, T. C. et al. Pink Moon: the petrogenesis of pink spinel anorthosites and implications concerning Mg-suite magmatism. Earth Planet. Sci. Lett. 403, 144–156 (2014).
Dhingra, D. et al. Compositional diversity at Theophilus Crater: understanding the geological context of Mg-spinel bearing central peaks. Geophys. Res. Lett. 38, L11201 (2011).
Jackson, C. R. et al. Visible-infrared spectral properties of iron-bearing aluminate spinel under lunar-like redox conditions. Am. Mineral. 99, 1821–1833 (2014).
Williams, K. B. et al. Reflectance spectroscopy of chromium-bearing spinel with application to recent orbital data from the Moon. Am. Mineral. 101, 726–734 (2016).
Treiman, A. H. & Gross, J. A rock fragment related to the magnesian suite in lunar meteorite Allan Hills (ALHA) 81005. Am. Mineral. 100, 414–426 (2015).
Warren, P. H. in Workshop on Moon in Transition: Apollo 14, KREEP, and Evolved Lunar Rocks Technical Report No. 89-03 (eds Taylor, G. J. & Warren, P. H.) 149–153 (LPI, 1989).
Hess, P. C. & Parmentier, E. M. A model for the thermal and chemical evolution of the Moon’s interior: implications for the onset of mare volcanism. Earth Planet. Sci. Lett. 134, 501–514 (1995).
Elkins Tanton, L. T., Van Orman, J. A., Hager, B. H. & Grove, T. L. Re-examination of the lunar magma ocean cumulate overturn hypothesis: melting or mixing is required. Earth Planet. Sci. Lett. 196, 239–249 (2002).
Boukaré, C.-E., Parmentier, E. & Parman, S. Timing of mantle overturn during magma ocean solidification. Earth Planet. Sci. Lett. 491, 216–225 (2018).
Nakamura, N., Masuda, A., Tanaka, T. & Kurasawa, H. Chemical compositions and rare-earth features of four Apollo 16 samples. In Proc. 4th Lunar Science Conference Vol. 2, 1407–1414 (Pergamon, 1973).
Laneuville, M., Taylor, J. & Wieczorek, M. A. Distribution of radioactive heat sources and thermal history of the Moon. J. Geophys. Res. Planets 123, 3144–3166 (2018).
Papike, J. J., Fowler, G. W., Shearer, C. K. & Layne, G. D. Ion microprobe investigation of plagioclase and orthopyroxene from lunar Mg-suite norites: implications for calculating parental melt REE concentrations and for assessing postcrystallization REE redistribution. Geochim. Cosmochim. Acta 60, 3967–3978 (1996).
Papike, J. J., Fowler, G. W. & Shearer, C. K. Orthopyroxene as a recorder of lunar crust evolution: an ion microprobe investigation of Mg-suite norites. Am. Mineral. 79, 796–800 (1994).
Connelly, J. N. & Bizzarro, M. Lead isotope evidence for a young formation age of the Earth–Moon system. Earth Planet. Sci. Lett. 452, 36–43 (2016).
Charlier, B., Grove, T. L., Namur, O. & Holtz, F. Crystallization of the lunar magma ocean and the primordial mantle–crust differentiation of the Moon. Geochim. Cosmochim. Acta 234, 50–69 (2018).
Rapp, J. F. & Draper, D. S. Fractional crystallization of the lunar magma ocean: updating the dominant paradigm. Meteorit. Planet. Sci. 53, 1432–1455 (2018).
Treiman, A. H., Kulis, M. E. J. & Glazner, A. F. Spinel-anorthosites on the Moon: impact melt origins suggested by enthalpy constraints. Am. Mineral. 104, 370–384 (2019).
Smith, P. M. & Asimow, P. D. Adiabat_1ph: a new public front-end to the MELTS, pMELTS, and pHMELTS models. Geochem. Geophys. Geosyst. 6, Q02004 (2005).
Asimow, P. D. & Ghiorso, M. S. Algorithmic modifications extending MELTS to calculate subsolidus phase relations. Am. Mineral. 83, 1127–1132 (1998).
Ghiorso, M. S., Hirschmann, M. M., Reiners, P. W. & Kress, V. C. The pMELTS: a revision of MELTS for improved calculation of phase relations and major element partitioning related to partial melting of the mantle to 3 GPa. Geochem. Geophys. Geosyst. 3, https://doi.org/10.1029/2001GC000217 (2002).
Elkins-Tanton, L. T., Burgess, S. & Yin, Q. Z. The lunar magma ocean: reconciling the solidification process with lunar petrology and geochronology. Earth Planet. Sci. Lett. 304, 326–336 (2011).
Morison, A., Labrosse, S., Deguen, R. & Alboussiere, T. Timescale of overturn in a magma ocean cumulate. Earth Planet. Sci. Lett. 516, 25–36 (2019).
O’Neill, H. S. C. & Pownceby, M. I. Thermodynamic data from redox reactions at high-temperatures 1: an experimental and theoretical assessment of the electrochemical ethod using stabilized zirconia electrolytes, with revised values for the Fe–FeO, Co–CoO, Ni–NiO and Cu–Cu2O oxygen buffers, and new data for the W–WO2 buffer. Contrib. Mineral. Petrol. 114, 296–314 (1993).
Dixon, J. E. & Stolper, E. M. An experimental study of water and carbon dioxide solubilities in mid-ocean ridge basaltic liquids: part II, applications to degassing. J. Petrol. 36, 1633–1646 (1995).
Yoder, H. Jr Diopside–anorthite–water at five and ten kilobars and its bearing on explosive volcanism. Year B Carnegie Inst. Wash. 64, 82–89 (1965).
Kushiro, I. The system forsterite–diopside–silica with and without water at high pressures. Am. J. Sci. 267, 269–294 (1969).
McCubbin, F. M. et al. Magmatic volatiles (H, C, N, F, S, Cl) in the lunar mantle, crust, and regolith: abundances, distributions, processes, and reservoirs. Am. Mineral. 100, 1668–1707 (2015).
Merrill, R. B. & Williams, R. J. The system anorthite–forsterite–fayalite–silica to 2 kbar with lunar petrologic applications. In Proc. 6th Lunar Science Conference 959–971 (Pergamon Press, 1975).
Breuer, D. in Solar System (ed. Trümper, J. E.) 323–344 (Springer, 2009).
We are grateful to A. Shahar (Carnegie) and the Carnegie Institution for Science for access to the experimental facilities there, E. Bullock (Carnegie) for assistance with EMP analyses and K. Donaldson Hanna (UCF) for kindly providing us an aliquot of Miyake-jima anorthite. This work was funded by a NASA Solar System Workings grant (NNX16AQ17G/80NSSC19K0752) to S.M.E.
The authors declare no competing interests.
Peer review information Primary Handling Editor: Stefan Lachowycz.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary discussion and Figs. 1–3.
Compositions of source components and experimental analogues.
Compositions of starting materials.
Summary of experimental conditions and results.
Compositional data for mineral and melt phases.
Parameters used in thermal evolution calculations.
About this article
Cite this article
Elardo, S.M., Laneuville, M., McCubbin, F.M. et al. Early crust building enhanced on the Moon’s nearside by mantle melting-point depression. Nat. Geosci. 13, 339–343 (2020). https://doi.org/10.1038/s41561-020-0559-4
Journal of Geophysical Research: Planets (2021)
The formation and evolution of the Moon’s crust inferred from the Sm-Nd isotopic systematics of highlands rocks
Geochimica et Cosmochimica Acta (2020)