The Apollo 14 Regolith: Chemistiy of cores 14210/14211 and 14220 and soils 14141, 14148, and 14149

Abstract

Chemical data for 31 major, minor, and trace elements were obtained by instrumental neutron activation analysis (INAA) for bulk and size fractions of drive tubes 14210/11 (39 cm) and 14220 (16.5 cm) and soils 14141, 14148, and 14149. Both cores are KREEPy and homogeneous in chemical composition. The meteoritic component varies from 3 to 7% in both cores. The heterogeneous Ni profiles suggest little in situ mixing of the cores since their emplacements. The bulk soils on the average contain 20% low‐K‐Fra Mauro basalt (LKFM) (62295), 10 to 15% mare basalt ( 14072), 6%anorthosite‐norite‐troctolite (ANT) and 59% high‐K KREEP. There are no significant intrasite chemical variations at the Apollo 14 site. Among the grain sizes, the coarse 1000–90, 90–20, and 20–10 μm fractions are similar in chemistry, but quite different from the < 10 μm fine fractions. The < 10 μm fine fractions comprise 5 to 15%of the bulk soils and are consistently more feldspathic and enriched in incompatible (LIL) elements relative to the coarse fractions. In the mature soils, agglutinates dominate the chemistry of the coarser fractions, and the similarity of LIL contents between the 1000–90 μm fractions and the < 10 μm fine fractions strongly suggests that agglutinates are derived from the fine fraction, which supports the F3 model of Papike et al [1981] Relative to the bulk soil, the < 10 μm fine fraction is enriched in Al2O3, CaO, Na2O, K2O, Ba, Sr, La(REE), Eu, and Th and depleted in MgO, FeO, Mn, and Sc. The observed varying degrees of enrichments and depletions can largely be explained by simple comminution of inesostasis and feldspar and their preferential incorporation into the finest fraction. Lateral mixing over short distances, simple comminution, and vertical mixing of the regolith are the dominant soil‐forming processes.

The lunar exosphere: The sputtering contribution

“…These can be divided into the following categories: Highland, Ti-rich Mare, Ti-poor Mare and Kreep. These names reflect the dominant petrological component in these soils deduced using the same component analysis as Laul et al (1982) and are between them believed to be broadly representative of the lunar surface. To simplify model calculations we simply averaged the values in each category (see Table 2), effectively giving a fourcomponent model for the composition of lunar soils.…”

Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron concentration

“…We assume these enrichments to be the result terrestrial contamination in the form of fracture and void-filling precipitates from ground or surface water as these elements have been reported as contaminants in other kinds of hot-desert meteorites (Dreibus et al 2003). As noted in more detail below, nearly all of the hot-desert meteorites are also enriched in Sr and Ba for the Schnetzler and Nava (1971), Lindstrom et al (1972), Philpotts et al (1972), Rose et al (1972), Wänke et al (1972), Willis et al (1972), andLaul et al (1982). Mare: Mean of data for Apollo crystalline basalts with <5% TiO 2 from the Mare Basalt Reference Suite of the Basaltic Volcanism Study Project (1981; Tables 1.2.9.1 through 1.2.9.4).…”

The lunar regolith: Chemistry, mineralogy, and petrology

“…Figure 57shows a comparison of the < 10/am fraction with the bulk <1 mm soil for six Apollo soils. The varying elemental ratios and differing magnitudes of enrichments and depletions ledLaul et al [1982] to rule out the addition of a uniform KREEP component to account for the highly KREEPy nature of the <10 /am fines. Instead, the data suggest a more random and variable process.…”