A.E. Fallick J. Hutchinson W. Hildreth A. N. Halliday 1984 <div id="abstracts" class="Abstracts u-font-serif text-s"><div id="ab1" class="abstract author" lang="en"><div id="aep-abstract-sec-id5"><p>The Bishop Tuff represents a single eruption of chemically zoned rhyolitic magma. Six whole rock samples spanning the compositional and temperature range yield initial<i>⁸⁷Sr/⁸⁶Sr</i><span>&nbsp;</span>of 0.7060–0.7092 and<i>δ¹⁸O</i><span>&nbsp;</span>of 5.9–10.3‰. Six constituent sanidines yield smaller ranges of initial<i>⁸⁷Sr/⁸⁶Sr</i><span>&nbsp;</span>of 0.7061–0.7069 and<i>δ¹⁸O</i><span>&nbsp;</span>of 6.7–7.9. In contrast<i>¹⁴³Nd/¹⁴⁴Nd</i><span>&nbsp;</span>ratios for the six whole rocks and two constituent magnetites exhibit negligible variation with a mean of<i>0.51258 ± 1</i>. These data are used to show that the phenocrysts were precipitated from an already chemically zoned liquid, that the zoning process involved negligible assimilation of, or exchange with, country rocks and that the extreme Sr and O isotopic disequilibria are probably the result of post-eruptive interaction with meteoric water. The parent magma had<i>ɛNd = −0.9, ɛSr = +23</i><span>&nbsp;</span>and<i>δ¹⁸O = 7‰</i><span>&nbsp;</span>and was formed from mantle-derived magmas and/or melts of lower crustal rocks isotopically similar to parts of the Sierra Nevada Batholith.</p></div></div></div><ul id="issue-navigation" class="issue-navigation u-margin-s-bottom u-bg-grey1"></ul> application/pdf 10.1016/0012-821X(84)90123-7 en Elsevier A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California article