Origin of lead from green glass of Apollo 15426: A search for primitive lunar lead.

Journal of Geophysical Research Solid Earth
By: , and 

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Abstract

A major obstacle in lunar U-Pb chronology is the elusiveness of the primary Pb isotopic composition and U/Pb ratio and therefore the Pb evolution for the early history of the moon. In an attempt to seek the primitive lunar Pb isotopic composition, green glass from lunar clod 15426,49 was studied for U-Th-Pb systematics because it is extremely Mg-rich and known to be the most primitive among sampled lunar volcanic rocks. Green glass and yellow impact glass were handpicked, washed with water, then washed in an acid mixture (0.3 N HBr + 0.2 N HF), and the washes and residues were analyzed. In contrast to the Pb from Apollo 17 orange glass, Pb from the surface of the green glass spherules is totally different from that of the spherule interior, but is similar to lunar surface lead. Data for the interior Pb yield a 207Pb/206Pb age of 3.41 Ga. Because of the low Pb concentration and high U/Pb ratio observed for the interior, the initial Pb was poorly defined. Nevertheless, the data indicate that lunar Pb evolved in an environment with 238U/204Pb = 19–55, which is considerably lower than those for mare basalts (around 300) but higher than values for the earth (6–8).

Publication type Article
Publication Subtype Journal Article
Title Origin of lead from green glass of Apollo 15426: A search for primitive lunar lead.
Series title Journal of Geophysical Research Solid Earth
DOI 10.1029/JB092iB04p0E361
Volume 92
Issue B4
Year Published 1987
Language English
Publisher American Geophysical Union
Description 11 p.
First page 361
Last page 371
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