<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Donald C. Noble</dc:contributor>
  <dc:creator>Carl E. Hedge</dc:creator>
  <dc:date>1971</dc:date>
  <dc:description>&lt;div class="article-section-wrapper js-article-section js-content-section  "&gt;&lt;p&gt;Upper Cenozoic basalts from southwestern Nevada and east-central California are unusually rich in both strontium (~ 1,200 ppm) and Sr&lt;sup&gt;87&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(initial Sr&lt;sup&gt;87&lt;/sup&gt;/Sr&lt;sup&gt;86&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;~ 0.707). The average Rb/Sr ratio of these basalts is too low to have generated the observed Sr&lt;sup&gt;87&lt;/sup&gt;/Sr&lt;sup&gt;86&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;ratio during the 4.6 b.y. of the Earth's existence, and the high strontium contents and low Rb/Sr ratios effectively rule out introduction to the basalts of the high Sr&lt;sup&gt;87&lt;/sup&gt;/Sr&lt;sup&gt;86&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;values through contamination by more radiogenic material during ascent through the crust. Instead, the basalts must have been derived from unusual mantle material in which an originally high Rb/Sr ratio was markedly lowered during an earlier phase of magmatic activity.&lt;/p&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1130/0016-7606(1971)82[3503:UCBWHS]2.0.CO;2</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Geological Society of America</dc:publisher>
  <dc:title>Upper Cenozoic basalts with high Sr87/Sr86 and Sr/Rb ratios, southern Great Basin, western United States</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>