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

Chemical Geology
By: , and 

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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. ?? 1974.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Iridium in some calcic and calc-alkalic batholithic rocks of the western United States
Series title Chemical Geology
DOI 10.1016/0009-2541(74)90101-6
Volume 14
Issue 1-2
Year Published 1974
Language English
Publisher Elsevier
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Chemical Geology
First page 117
Last page 122