Extraterrestrial data are not likely to provide quantitative values for the chemical composition of the upper mantle. Three groups of terrestrial materials, ultramafic rocks, olivine nodules from basalts, and garnet peridotite nodules from kimberlites, probably are directly derived from the upper mantle. Each group has a wide range of composition. However, the estimates for the composition of original or undepleted mantle derived independently from each source approach a common value. When this composition is recalculated as probable mineral assemblages, the pyroxene peridotite and garnet peridotite zones both contain about 65% of olivine. The range of composition of each group is consistent with compositional heterogeneity in the upper mantle.
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Harris et al. (1967) studied this question.
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