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Early crust building enhanced on the Moon’s nearside by mantle melting-point depression


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.

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Fig. 1: The effects of KREEP on melt production in Mg-suite sources.
Fig. 2: The composition of experimental olivine compared with Apollo Mg-suite samples.
Fig. 3: Calculated REE abundances in experimental melts compared with Mg-suite parental melts.
Fig. 4: The ΔT of Mg-suite source regions due to radiogenic heating.

Data availability

The data supporting the findings of this study are available within the article and its Supplementary Information files.

Code availability

The code used for the thermal evolution calculations presented here is available from M.L. upon request. Email:


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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.

Author information




S.M.E., F.M.M. and C.K.S. developed the concept of this study. S.M.E. conducted all experiments and analyses. M.L. conducted all heat production calculations. All authors contributed to data interpretation and preparation of the manuscript.

Corresponding author

Correspondence to Stephen M. Elardo.

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Supplementary information

Supplementary Information

Supplementary discussion and Figs. 1–3.

Supplementary Table 1

Compositions of source components and experimental analogues.

Supplementary Table 2

Compositions of starting materials.

Supplementary Table 3

Summary of experimental conditions and results.

Supplementary Table 4

Compositional data for mineral and melt phases.

Supplementary Table 5

Parameters used in thermal evolution calculations.

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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).

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