M. Tatsumoto J.N. Rosholt R. J. Knight B.L.K. Somayajulu 1966 <div id="abstracts" class="Abstracts u-font-serif"><div id="ab1" class="abstract author" lang="en"><div id="aep-abstract-sec-id7"><p>Radioisotope analyses of basalt samples from Hawaii, Japan, and Iwo Jima show that: (1)²³⁴U and²³⁸U are virtually in radioactive equilibrium, (2)²³⁰Th exceeds equilibrium values in all these samples, (3)²¹⁰Pb concentrations range from 10–200% of the equilibrium values and average 30% deficient, and (4)²²⁶Ra is probably not in equilibrium with²³⁴U.</p><p>The source regions of the basalts or magma forming processes are open systems, chemically. The enrichment of some of the uranium-daughter nuclides is insufficient to account for the excess²⁰⁶Pb in volcanic rocks.</p><p>The isotopic composition of lead and specific activity of²¹⁰Pb in sublimates from Showa-shinzan, Japan are also reported.</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(66)90032-X en Elsevier Disequilibrium of the 238U series in basalt article