ArticlesAge Measurements

Rubidium-Strontium Chronology and Chemistry of Lunar Material

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Science  30 Jan 1970:
Vol. 167, Issue 3918, pp. 474-476
DOI: 10.1126/science.167.3918.474


Igneous lunar rocks divide into two chemical types, probably representing two rock units. They form separate close groups on the isochron diagram; no total rock age is valid unless the rocks are cogenetic. Mineral isochrons prove that one type has an age of 3.80 ±0.11 billion years, equal to the line joining total-rock groups, and the initial ratio of strontium-87 to strontium-86 of both types is close to 0.6994. Soil and breccias chemically resemble a mixture of the two igneous types, with a superimposed variation of mineral components, plus a small transferred component rich in nickel, copper, zinc, and possibly stron-tium-87

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