Iridium in some calcic and calc-alkalic batholithic rocks of the western United States

L. P. Greenland; D. Gottfried; R.I. Tilling

doi:10.1016/0009-2541(74)90101-6

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Iridium in some calcic and calc-alkalic batholithic rocks of the western United States

L. P. Greenland·D. Gottfried·R.I. Tilling

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Abstract

Neutron-activation determinations of Ir in rocks of the Southern California and Boulder (Montana) batholiths show that the Ir content is low and variable in both batholiths, extending over 1 to 2 orders of magnitude and having a combined median of 0.006 ppb Ir. The data suggest that the calc-alkalic Boulder batholith (0.002–0.5 ppb Ir, median 0.007) may be slightly enriched in Ir relative to the calcic Southern California batholith (< 0.001–0.12 ppb Ir, median 0.005). No conspicuous relationship between Ir content and differentiation parameters is evident; however, the Boulder batholith rocks do show a slight tendency to concentrate Ir in the more mafic rocks. Our results in conjunction with previous analyses of mafic rocks leads to a crustal-abundance estimate of 0.03 ppb Ir

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Chemical Geology Article

Source-reported bounding extent: 31.12819929911196° to 49.95121990866204° latitude; -126.73828125° to -103.0078125° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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L. P. Greenland, D. Gottfried, R.I. Tilling. 1974. Iridium in some calcic and calc-alkalic batholithic rocks of the western United States. https://doi.org/10.1016/0009-2541(74)90101-6

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