Norman J. Hubbard

The composition and derivation of Apollo 12 soils

Abstract A feldspathic orthopyroxene rich rock, with abundant Ca phosphates and K-feldspar, and chemically comparable glass fragments are found in the Apollo 12 soil. This material is rich in K, Rb, P and rare-earth elements. Three Apollo 12 soils and at least one breccia are quantitatively matched by mixtures of this material (designated KREEP) and average Apollo 12 basalt. The dark material in 12013 is similar to KREEP, and Luny Rock I (Apollo 11) is probably identical. KREEP, or similar materials, can also be the “magic” or “cryptic” component of Apollo 11 soil.

Chemical composition of lunar anorthosites and their parent liquids

Abstract Two types of lunar anorthosites, associated anorthositic materials and parent non-mare basalts exist on the moon. One type is low in alkalies and trace elements and includes 15415 and Apollo 11 anorthositic materials and derives from low K non-mare basalts. The second type is high in alkalies and trace elements and derived from the KREEP type of non-mare basalts.

A chemical comparison of oceanic ridge, Hawaiian tholeiitic and Hawaiian alkalic basalts*

Abundance data (Al 2 O 3 , TiO 2 , Sr. Zr and REE) for two important groups of basalts (oceanic ridge and Hawaiian) are compared. The average concentrations of Al 2 O 3 , TiO 2 and Zr are quite different for the two groups but extensive overlap also occurs. TiO 2 and Zr are inversely covariant with Al 2 O 3 for oceanic ridge and Hawaiian basalts. The Al 2 O 3 and TiO 2 data are consistent with the experimental data of Green and Ringwood [5] and MacGregor [25] and suggest that the concentrations of Al 2 O 3 , TiO 2 and Zr in a wide range of basalt types are dependent on the depth of magma segregation. The two basaltic groups are almost completely different in their Sr concentration and REE abundance patterns. The concentrations of Sr and the REE abundance patterns are essentially independent of the concentrations of Al 2 O 3 , TiO 2 and Zr. The Sr and REE data can be qualitatively explained by assuming varying degrees of partial melting to form the different liquids observed at the surface.

Abundance of alkali metals, alkaline and rare earths, and strontium-87/ strontium-86 ratios in lunar samples.

The variation in trace element abundance patterns indicates that lunar igneous rocks are the product of extensive igneous fractionation. Variations in the Sr87/ Sr86 ratio indicate that these rocks crystallized 3.5�0.3 x 109 years ago.

The chemical composition of soil from the Apollo 16 and Luna 20 sites.

Abstract The concentrations of the rare earth elements (REE), K, Rb, Sr, Ba, U, Zr and Cr for the Luna 20 soil and four different Apollo 16 soils are reported. These trace element abundances imply: (1) that the lunar highlands consist of a mixture of rocks rich in large ion lithophile (LIL) elements and LIL-element impoverished anorthosites; or (2) that the bulk of the aluminum-rich crust did not originate by upward segregation of plagioclase in a primitive liquid shell. The Luna 20 soil is distinguished from the Apollo 16 soil by lower aluminum and LIL element abundances.

Rare earth, alkaline and alkali metal and 87/86Sr data for subsamples of lunar sample 12013

Abstract Four subsamples of lunar rock 12013 have been analyzed. A “whole rock” sample has high rare earth and very high Ba concentrations with the chondrite normalized abundance pattern showing a slight enrichment in Ba and Ce and the usual large negative Eu anomaly. The light and dark components of this rock have similar REE. The light colored materials are commonly quite enriched in radiogenic 87 Sr and the Rb-Sr system appears to have lost Rb.

RARE EARTH ABUNDANCES IN SOIL AND ROCKS FROM THE OCEAN OF STORMS.

Abstract The rare earth abundance patterns in Apollo 12 basalts have much lower concentrations and smaller Eu anomalies than Apollo 12 soil and all analyzed Apollo 11 samples. The rare earth abundance patterns of Apollo 12 basalts are similar to and overlap those of achondritic meteorites. A partial melting model can explain the rare earth data for lunar samples.

Chemistry of lunar basalts with very high alumina contents.

A chemically distinct group of lunar rocks with the trace element characteristics of basaltic lunar rocks is apparently ubiquitous on the lunar surface. Such rocks have been found at the Apollo 15, Apollo 16, and Luna 20 landing sites. They may be derived from the plains-forming material that has been designated Cayley Formation.

Chemical features of the Luna 16 regolith sample

Abstract The Luna 16 regolith sample differs from Apollo 11, 12 and 14 regolith and basalt samples by having smaller negative Eu and Sr anomalies and nearly chondritic Eu/Sm and Eu/Sr ratios although the overall REE, Ba, Sr and U concentrations are 25 to 45 times chondrites. Major element data, in particular FeO vs. Al 2 O 3 , show that the Luna 16 regolith sample is composed of materials that follow a quantitatively different Fe/Al variation than do Apollo 11, 12, 14 and 15 samples. The small Eu and Sr anomalies and the displaced Fe/Al variation are two chemical features unique to the Luna 16 regolith sample. The Luna 16 regolith sample can contain little if any of the rock types abundant at Apollo sites, thus indicating that the unique chemical features are typical of local or nearby materials and indicate a separate petrogenetic province for major component rock types of the Luna 16 regolith.