<?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>M. A. Lanphere</dc:contributor>
  <dc:contributor>Richard C. Erd</dc:contributor>
  <dc:contributor>M.C. Blake Jr.</dc:contributor>
  <dc:creator>G.K. Czamanske</dc:creator>
  <dc:date>1978</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;K-Ar ages have been determined for sulfide minerals for the first time. The occurrence of adequate amounts of potassium-bearing sulfides with ideal compositions K&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;Fe&lt;/span&gt;&lt;sub&gt;10&lt;/sub&gt;&lt;span&gt;S&lt;/span&gt;&lt;sub&gt;14&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(∼10 wt.% K) and KFe&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;S&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(∼16 wt.% K) in samples from a mafic alkalic diatreme at Coyote Peak, California, prompted an attempt to date these materials. K&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;Fe&lt;/span&gt;&lt;sub&gt;10&lt;/sub&gt;&lt;span&gt;S&lt;/span&gt;&lt;sub&gt;14&lt;/sub&gt;&lt;span&gt;, a massive mineral with conchoidal fracture, gives an age of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;29.4 ± 0.5m.y.(&lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar)&lt;/i&gt;&lt;span&gt;, indistinguishable from the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;28.3 ± 0.4m.y.(&lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar)&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;30.2 ± 1.0m.y.&lt;/i&gt;&lt;span&gt;8 (conventional K-Ar) ages obtained for associated phlogopite (8.7 wt.% K). KFe&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;S&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;, a bladed, fibrous sulfide, gives a younger age,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;26.5 ± 0.5m.y.(&lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar)&lt;/i&gt;&lt;span&gt;, presumably owing to Ar loss.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0012-821X(78)90079-1</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Age measurements of potassium-bearing sulfide minerals by the 40Ar/39Ar technique</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>