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Results for “rare-earth elements”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1972

The lunar interior

The compressional velocities are estimated for materials thought to be important in the lunar interior and compared with lunar seismic results. The lower lunar crust has velocities appropriate for basalts or anorthosites. Anorthosite is preferred if lunar basalts result from a small degree of partial melting. The high velocities associated with the uppermost mantle imply high densities and a change to a lighter assemblage at depths of the order of 120 km. Ca- and Al-rich minerals are important components of both the lower crust and the upper mantle. Most of the moon may have accreted from refractory material rich in Ca, Al, U, and the rare-earth elements. The important mineral of the upper mantle is garnet; possible accessory minerals are kyanite, spinel and rutile. If the seismic results stand up, the high-velocity layer in the moon is more likely to be a high-pressure form of anorthosite than eclogite, pyroxenite, or dunite.

Anderson, D. L.↗
NASA NTRS1971

Geochemical aspects of some Japanese lavas.

K, Rb, Sr, Ba and rare-earth concentrations in some Japanese lavas have been determined by mass-spectrometric stable-isotope dilution. The samples fall into three rare-earth groups corresponding to tholeiitic, high alumina and alkali basalts. Japanese tholeiites have trace element characteristics similar to those of oceanic ridge tholeiites except for distinctly higher relative concentrations of Ba. Japanese lavas may result from various degrees of partial fusion of amphibole eclogite.

Philpotts, J. A.↗
NASA NTRS1972

Luna 16 - Some Li, K, Rb, Sr, Ba, rare-earth, Zr, and Hf concentrations.

Concentrations of Li, K, Rb, Sr, Na, rare-earths, Zr and Hf have been determined for some Luna 16 core materials by mass-spectrometric isotope-dilution. Two regolith fines samples from different depths in the core, and four rock-chips, including both igneous rocks and breccias, have similar trace-element concentrations. The Luna 16 materials have general lunar trace-element characteristics but differ from other returned lunar samples in a manner that suggests the presence of excess feldspar. Unless the Luna 16 igneous rocks are fused soils, they appear to represent either partial plagioclase cumulates or the least differentiated igneous material yet returned from the moon. The similarity in trace-element concentrations of the igneous rocks and the fines would then suggest largely local derivation of the Luna 16 regolith.

Philpotts, J. A.↗