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<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>L. D. White</dc:contributor>
  <dc:contributor>J. B. Rapp</dc:contributor>
  <dc:creator>William C. Evans</dc:creator>
  <dc:date>1988</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Five samples of hydrothermal fluids from two vent areas on the southern Juan de Fuca Ridge were analyzed for dissolved gases. Concentrations in the end-member hydrothermal fluid of H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(270–527 μmol/kg), CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(82–118 μmol/kg), and CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(3920–4460 μmol/kg) are well above values in ambient seawater and are similar to concentrations reported for other ridge crest hydrothermal systems. The carbon isotopic ratios of the CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(δ&lt;/span&gt;&lt;sup&gt;13&lt;/sup&gt;&lt;span&gt;C = −17.8 to −20.8) and CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(δ&lt;/span&gt;&lt;sup&gt;13&lt;/sup&gt;&lt;span&gt;C = −3.6 to −4.7) suggest that at least some of the CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;in the fluids is basalt-derived. The range of δ&lt;/span&gt;&lt;sup&gt;13&lt;/sup&gt;&lt;span&gt;C values for the basalt-derived CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;is −6.8 to −9.7, calculated by assuming conservation of recharge ΣCO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;during hydrothermal circulation. Apparent temperatures of equilibration between the CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and the basalt-derived CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;range from 640°C to 750°C. Small amounts of ethane (C&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;H&lt;/span&gt;&lt;sub&gt;6&lt;/sub&gt;&lt;span&gt;/CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;≅ 0.9 × 10&lt;/span&gt;&lt;sup&gt;−3&lt;/sup&gt;&lt;span&gt;−2.2 × 10&lt;/span&gt;&lt;sup&gt;−3&lt;/sup&gt;&lt;span&gt;), propane, and butane detected in the samples may also have formed in the basalt. One sample of almost pure (95.5%) hydrothermal fluid contained a significant fraction, up to 63% and 74%, respectively, of the recharge Ar and N&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;. This suggests that the fluid has not undergone extensive vapor-liquid phase separation.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/JB093iB12p15305</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>Geochemistry of some gases in hydrothermal fluids from the southern Juan de Fuca Ridge</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>