The proposal by Hubbard et al. (1) that "Very High Alumina basalt" ("VHA basalt") may represent an important primary lunar magma type neglects consideration of certain well-characterized high-magnesium highland rocks, among them spinel troctolite from Luna 20 (2) and Apollo 16 samples (3) and dunite from Apollo 17 samples (4), and the possibility that "VHA basalt" may in fact have originated by...

Introduction: Lunar mare basalts are products of partial melting of the lunar interior, thus are keys to understand the chemical compositions of the source mantle. However, the iron-enrichment of the mare basalt samples returned by Apollo and Luna missions, compared to the terrestrial basalts, have led to an inference that the mare basalt hand specimen do not represent the primary magma composi...

Cratonic mantle eclogite xenoliths occur with diamond-bearing kimberlite. The modes and mineral compositions of eclogite contain important information on their origin, physical-chemical conditions of formation, and their geophysical properties. We have used the pseudosection option of the program PERPLEX to explore how mineral assemblage, abundance, and composition vary with bulk composition, t...

Introduction: Only 5 meteorites were classified into unbrecciated lunar mare basalt so far, although there are about 40 lunar meteorites known to date. NWA 032 and its paired meteorite NWA 479 (NWA) are such crystalline mare basalts, and show a porphy-ritic texture composed of euhedral olivine and pyrox-ene grains with dendritic mesostasis of pyroxene, pla-gioclase and accessory minerals (ilmen...

Introduction: Assimilation has been called upon in numerous occasions to explain various petrologic and geochemical observations of the igneous rocks on the Moon. A well known example is the assimilation of ilmenite-bearing late cumulates (and KREEP) to the low Ti primary magmas at shallow levels, that has been used to explain the high Ti magmas observed on the lunar surface [1]-[3]. An alterna...

We report new high-precision laser fluorination three-isotope oxygen data for lunar materials. Terrestrial silicates with a range of δO values (−0.5 to 22.9‰) were analyzed to independently determine the slope of the terrestrial fractionation line (TFL; λ=0.5259±0.0008; 95% confidence level). This new TFL determination allows direct comparison of lunar oxygen isotope systematics with those of E...

Lunar sample 15474,4 is a tiny fragment of olivine-augite vitrophyre that is a mare basalt. Although petrographically distinct from all other Apollo 15 samples, it has been ignored since its first brief description. Our new petrographic and mineral chemical data show that the olivines and pyroxenes are distinct from those in other basalts. The basalt cooled and solidified extremely rapidly; som...

The boundary between ice and basalt on Earth is an analogue for some near-surface environments of Mars. We investigated neutrophilic iron-oxidizing microorganisms from the basalt-ice interface in a lava tube from the Oregon Cascades with perennial ice. One of the isolates (Pseudomonas sp. HerB) can use ferrous iron Fe(II) from the igneous mineral olivine as an electron donor and O(2) as an elec...

The study of volcanic geochemistry is one of the main gateways for investigating the Earth’s mantle. One important topic in the field is that of nickel (Ni) in the mineral olivine. While Ni is a compatible element in olivine, its high concentration at a given MgO content is not well understood. A variety of hypotheses have been proposed, including attributing presence of Ni to pyroxenite source...