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Published January 1972 | public
Journal Article

U-Th-Pb analyses of soil from the Sea of Fertility

Abstract

The isotopic composition of lead was determined on soil samples from two levels of the Luna 16 core. The lead was distinctly radiogenic and yielded ²⁰⁷Pb/²⁰⁶Pb model ages of 4.8 AE. This is interpreted as reflecting early lunar differentiation processes. The most reliable value of ²⁰⁸Pb/²⁰⁴Pb = 111 shows that the Luna 16 soils are significantly less radiogenic than found for other lunar soils. The elemental concentrations are Pb ∼ 0.9 ppm, U ∼ 0.3 ppm and Th ∼ 1.2 ppm with a Th/U ratio of 3.8. The U concentration is the lowest so far found for lunar soils. These data indicate that only a very small amount of magic component kreeputh into the Luna 16 soil.

Additional Information

We are grateful to the Soviet Academy of Sciences and The National Aeronautics and Space Administration for arranging the exchange of lunar examples. We thank the Lunar Sample Analysis Planning Team for entrusting the Lunatic Asylum with part of these samples. We are indebted to Lily Ray whose skillful and enthusiastic support helped us meet the deadline. Her efficient and intelligent aid was critical to many phases of this work. This work was supported by NASA under NAS-9-8074.

Additional details

Created:
August 22, 2023
Modified:
October 24, 2023