<?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>D.A. Crown</dc:contributor>
  <dc:contributor>Ronald Greeley</dc:contributor>
  <dc:creator>T.K.P. Gregg</dc:creator>
  <dc:date>1998</dc:date>
  <dc:description>&lt;p&gt;&lt;span class="TextRun SCXW97869839 BCX8" lang="EN-US" xml:lang="EN-US" data-contrast="auto"&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Mars Transverse Mercator (MTM) -20252 &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;quadrangle&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; contains the volcano &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Tyrrhena&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Patera, a low, broad structure that has summit depressions and is dissected by prominent radial channels&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; (fig. 1). &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Tyrrhena&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Patera is surrounded by cratered plains materials on the western edge of Hesperia P&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;lanum, &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;~&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;2,000 km northeast of the center of the Hellas basin (Greeley and Guest, 1987; U. S.&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Geological Survey, 1991). &lt;/span&gt;&lt;span class="AdvancedProofingIssue SCXW97869839 BCX8"&gt;On the basis of&lt;/span&gt; &lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Mariner&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; 9 data, &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Tyrrhena&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Patera &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;was interpreted to be a shield volcano, composed of fluid basic or ultrabasic lavas&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; (Peterson, 1978; Pike, 1978). Analysis of Viking Orbiter images led&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Greeley and &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Spudis&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; (1981) to suggest that &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Tyrrhena&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Patera comprises pyroclastic deposits &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;p&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;roduced by explosi&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;ve &lt;/span&gt;&lt;span class="SpellingError SCXW97869839 BCX8"&gt;hydromagmatic&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; eruption&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;; Greeley and Crown (1990) support a pyroclastic origin for &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;Tyrrhena&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; Patera shield &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;materials&lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt; and assess several eruption styles for the volcano (see also Crown and Greeley, &lt;/span&gt;&lt;span class="NormalTextRun SCXW97869839 BCX8"&gt;1993).&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3133/i2556</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Geologic map of part of the Tyrrhena Patera region of Mars (MTM Quadrangle-20252)</dc:title>
  <dc:type>reports</dc:type>
</oai_dc:dc>