Isotopic Composition of Strontium in Volcanic Rocks from Oahu

Abstract

Analysis of several well-documented specimens from each of the three volcanic series on Oahu gives the following mean ratios of Sr⁸⁷ to Sr⁸⁶: the Waianae series, 0.7030 ± 0.00010 (σ); the Koolau series, 0.70385± 0.00009 (σ); and the Honolulu series, 0.7029 +± 0.00006 ( σ). The mean ratio of Sr⁸⁷ to Sr⁸⁶ of the Koolau series specimens is significantly higher than the means of the other two series. With one exception, significant differences in Sr⁸⁷/ Sr⁸⁶ within a series were not found, even though some large compositional differences existed.