thumbnail

Isotopic composition of lead in oceanic basalt and its implication to mantle evolution

Earth and Planetary Science Letters
By:
https://doi.org/10.1016/0012-821X(78)90126-7

Links

Abstract

New data are given in this report for (1) Pb isotopic compositions and U, Th, and Pb concentrations of basalts from the island of Hawaii; (2) redetermined Pb isotopic compositions of some abyssal tholeiites; and (3) U, Th, and Pb concentrations of altered and fresh abyssal basalts, and basalt genesis and mantle evolution are discussed. The Th/U ratios of abyssal and Japanese tholeiites are distinctly lower than those of tholeiites and alkali basalts from other areas. It is thought that these low values reflect a part of the mantle depleted in large ionic lithophile elements. Thus a mantle evolution model is presented, in which Th/U ratios of the depleted zone in the mantle have decreased to ∼2, and U/Pb ratios have increased, showing an apparent ∼1.5-b.y. isochron trend in the 207Pb/204Pb vs. 206Pb/204Pb plot. The Pb isotopic compositions of basalts from the island of Hawaii are distinct for each of the five volcanoes, and within each volcano, Pb's of tholeiites and alkali basalts are similar. An interaction between partially melted material (hot plume?) of the asthenosphere and the lithosphere is suggested to explain the trend in the Pb isotopic compositions of Hawaiian basalts.

    Publication type Article
    Publication Subtype Journal Article
    Title Isotopic composition of lead in oceanic basalt and its implication to mantle evolution
    Series title Earth and Planetary Science Letters
    DOI 10.1016/0012-821X(78)90126-7
    Volume 38
    Issue 1
    Year Published 1978
    Language English
    Publisher Elsevier
    Description 25 p.
    First page 63
    Last page 87
    Google Analytic Metrics Metrics page
    Additional publication details