In the last decade, several studies have reported enrichments of the heavy isotopes of moderately volatile elements in lunar mare basalts. However, the mechanisms controlling the isotope fractionation are still debated and may differ for elements with variable geochemical behaviour. Here, we present a new comprehensive dataset of mass-dependent copper isotope compositions (delta 65Cu) of 30 mare basalts sampled during the Apollo missions. The new delta 65Cu data range from +0.14 %o to +1.28 %o (with the exception of two samples at 0.01 %o and -1.42 %o), significantly heavier than chondrites and the bulk silicate Earth. A comparison with mass fractions of major and trace elements and thermodynamic constraints reveals that Cu isotopic variations within different mare basalt suites are mostly unrelated to fractional crystallisation of silicates or oxides and late-stage magmatic degassing. Instead, we propose that the delta 65Cu average of each suite is representative of the composition of its respective mantle source. The observed differences across geographically and temporally distinct mare basalt suites, suggest that this variation relates to large-scale processes that formed isotopically distinct mantle sources. Based on a Cu isotope fractionation model during metal melt saturation in crystal mush zones of the lunar magma ocean, we propose that distinct delta 65Cu compositions and Cu abundances of mare basalt mantle sources reflect local metal melt-silicate melt equilibration and trapping of metal in mantle cumulates during lunar magma ocean solidification. Differences in delta 65Cu and mass fractions and ratios of siderophile elements between low- and high-Ti mare basalt sources reflect the evolving compositions of both metal and silicate melt during the late cooling stages of the lunar magma ocean.

Chang'E-5 samples provide unique insights into the composition of the lunar interior similar to 2 billion years ago, but geochemical models of their formation show a significant degree of discrepancy. Trace element abundance measurements in olivine grains in Chang'E-5 sub-sample CE5C0600YJFM002GP provide additional constraints on the basalt source. Geochemical modeling indicates that low-degree (4 %) batch melting of an olivine-pyroxenite lunar magma ocean cumulate, incorporating high levels of trapped lunar magma ocean liquid and plagioclase, can reproduce the rare earth element, Sr, Rb, Sc, Co and Ni abundances in our and previously reported Chang'E-5 samples, as well as observed Rb-Sr and Sm-Nd isotope systematics. Overall, these results strengthen the direct geochemical links between lunar magma ocean evolution and basaltic volcanism occurring similar to 2.5 billion years later. Additionally, Chang'E-5 high-Fo olivine is enriched in the volatile element Ge (1.38-3.94 mu g/g) by similar to 2 orders of magnitude compared to modeled results (< 0.02 mu g/g). As Ge is a mildly compatible element with bulk Ge partition coefficients close to 1, a Ge-depleted initial LMO proposed by previous research cannot yield a high-Ge mantle source for Chang'E-5 basalt, even when invoking assimilation of high-Ge LMO cumulates. The overabundance of Ge requires either a high-Ge, volatile rich initial bulk Moon with chondritic composition or a late Ge chloride vapor-phase metasomatism.

Due to the lack of rock samples directly from the deep part of the Moon, experiments and numerical simulation are effective methods to understand the early evolution of the Moon. Since the 1970s, the Lunar Magma Ocean (LMO) evolution model has been verified and modified by a large number of experimental petrology and geochemical work. However, the original composition of the Moon and the depth of its magma ocean, which are the two most critical parameters of LMO models remain controversial. The different lunar crust thickness estimated from lunar seismic data compared to that estimated from gravity data, the volatile content of lunar samples, and the widespread of Mg and Al-rich spinet (Cr (#) <5) discovered from interpreting the new remote sensing data affect our assessment on the starting composition and the depth of LMO, and the fractional crystallization process thereafter. In this paper, we review a series of high temperature and high pressure experimental petrology and experimental geochemistry results on the Moon's early evolution by focusing on: (1) The influence of refractory elements and volatile content of LMO's composition and its depth on the thickness of lunar crust and the Moon's mineral constitution formed through early differentiation. (2) The rationality of stability of high pressure mineral garnet deep inside lunar mantle and it effect on the distribution of trace elements during the evolution of lunar. (3) The petrogenesis of the Moon's special components, including volcanic glasses and Mg-suite, and their indication on the composition of the Moon's deep interior. (4) The constraint of lunar core composition on the Moon's material source, especially the abundance of trace elements. Based on the latest observation and the new analysis results of lunar samples, we evaluate the existing LMO evolution models and propose a LMO model with garnet as an important constituent mineral inside the Moon. We also discuss the necessary work need to be done to improve the new LMO model.

Volatile-bearing lunar surface and interior, giant magmatic-intrusion-laden near and far side, globally distributed layer of purest anorthosite (PAN) and discovery of Mg-Spinel anorthosite, a new rock type, represent just a sample of the brand new perspectives gained in lunar science in the last decade. An armada of missions sent by multiple nations and sophisticated analyses of the precious lunar samples have led to rapid evolution in the understanding of the Moon, leading to major new findings, including evidence for water in the lunar interior. Fundamental insights have been obtained about impact cratering, the crystallization of the lunar magma ocean and conditions during the origin of the Moon. The implications of this understanding go beyond the Moon and are therefore of key importance in solar system science. These new views of the Moon have challenged the previous understanding in multiple ways and are setting a new paradigm for lunar exploration in the coming decade both for science and resource exploration. Missions from India, China, Japan, South Korea, Russia and several private ventures promise continued exploration of the Moon in the coming years, which will further enrich the understanding of our closest neighbor. The Moon remains a key scientific destination, an active testbed for in-situ resource utilization (ISRU) activities, an outpost to study the universe and a future spaceport for supporting planetary missions.

Mineralogy of the Lunar surface provides important clues for understanding the composition and evolution of the primordial crust in the Earthe-Moon system. The primary rock forming minerals on the Moon such as pyroxene, olivine and plagioclase are potential tools to evaluate the Lunar Magma Ocean (LMO) hypothesis. Here we use the data from Moon Mineralogy Mapper (M-3) onboard the Chandrayaan-1 project of India, which provides Visible/Near Infra Red (NIR) spectral data (hyperspectral data) of the Lunar surface to gain insights on the surface mineralogy. Band shaping and spectral profiling methods are used for identifying minerals in five sites: the Moscoviense basin, Orientale basin, Apollo basin, Wegener crater-highland, and Hertzsprung basin. The common presence of plagioclase in these sites is in conformity with the anorthositic composition of the Lunar crust. Pyroxenes, olivine and Fe-Mg-spinel from the sample sites indicate the presence of gabbroic and basaltic components. The compositional difference in pyroxenes suggests magmatic differentiation on the Lunar surface. Olivine contains OH/H2O band, indicating hydrous phase in the primordial magmas. (C) 2016, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.