<?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>S.L. Brantley</dc:contributor>
  <dc:contributor>J. M. Thompson</dc:contributor>
  <dc:contributor>G.L. Rowe</dc:contributor>
  <dc:contributor>A.A. Nyblade</dc:contributor>
  <dc:contributor>C. Moshy</dc:contributor>
  <dc:creator>K.W. Koepenick</dc:creator>
  <dc:date>1996</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;As a comparison to airborne infrared (IR) flux measurements, ground-based sampling of fumarole and soil gases was used to characterize the quiescent degassing of CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;from Oldoinyo Lengai volcano. Aerial and ground-based measurements are in good agreement: ∼75% of the aerially measured CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;flux at Lengai (0.05–0.06 × 10&lt;/span&gt;&lt;sup&gt;12&lt;/sup&gt;&lt;span&gt;&amp;nbsp;mol yr&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;or 6000–7200 tonnes CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;d&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;) can be attributed to seven large crater vents. In contrast to Etna and Vulcano Island, where 15–50% of the total CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;flux emanates diffusely through the volcanic flanks, diffuse emissions were measured only within 500 m of the crater rim at Lengai, contributing &amp;lt;2% of the total flux. The lack of extensive flank emissions may reflect the dimensions of the magma chamber and/or the lack of a shallow fluid flow system. Thermodynamic restoration of fumarole analyses shows that gases are the most CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;-rich and H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;O-poor reported for any volcano, containing 64–74% CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, 24–34% H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;O, 0.88–1.0% H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, 0.1–0.4% CO and &amp;lt;0.1% H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;S, HCl, HF, and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;. Volatile emissions of S, Cl, and F at Oldoiyno Lengai are estimated as 4.5, 1.5, and 1.0 × 10&lt;/span&gt;&lt;sup&gt;7&lt;/sup&gt;&lt;span&gt;&amp;nbsp;mol yr&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;, respectively. Accuracy of the airborne technique was also assessed by measuring the C emission rate from a coal-burning power plant. CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fluxes were measured within ±10% near the plant; however, poor resolution at increased distances caused an underestimation of the flux by a factor of 2. The relatively large CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fluxes measured for alkaline volcanoes such as Oldoinyo Lengai or Etna may indicate that midplate volcanoes represent a large, yet relatively unknown, natural source of CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/96JB00173</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Volatile emissions from the crater and flank of Oldoinyo Lengai volcano, Tanzania</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>