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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>R.L. Ericksen</dc:contributor>
  <dc:creator>J. S. Stuckless</dc:creator>
  <dc:date>1976</dc:date>
  <dc:description>&lt;p&gt;Twelve whole-rock samples of volcanic rocks and a composite of 11 basanitoid samples from Ross Island and vicinity, Antarctica show a narrow range of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr ratios from 0.7030&lt;sub&gt;5&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to 0.7033&lt;sub&gt;9&lt;/sub&gt;. This range is consistent with a model of differentiation from a single parent magma, but the data allow a 30% variation in the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;87&lt;/sup&gt;Rb/&lt;sup&gt;86&lt;/sup&gt;Sr ratio in the source region if the average ratio is less than 0.057 and if the source region has existed as a closed system for 1.5 b.y. Megacrysts of titaniferous augite, kaersutite, and anorthoclase are isotopically indistinguishable from the host volcanic rocks and therefore are probably cogenetic with the volcanic sequence. A single trachyte sample is isotopically distinct from the rest of the volcanic rocks and probably was contaminated with crustal strontium.&lt;/p&gt;&lt;p&gt;Ultramafic and mafic nodules found in association with basanitoids and trachybasalts have&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr ratios ranging from 0.7027&lt;sub&gt;5&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to 0.7057&lt;sub&gt;5&lt;/sub&gt;. Several of these nodules exhibit evidence of reaction with the melt and are isotopically indistinguishable from their hosts, but data for seven granulite-facies nodules show an apparent isochronal relationship. Although this isochron may be fortuitous, the resulting age of 158±22 m.y. is similar to ages reported for the voluminous Ferrar Dolerites, and suggests isotopic re-equilibration within the lower crust and upper mantle. These nodules are not genetically related to the Ferrar Dolerites, as evidenced by their lower initial&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr ratios.&lt;/p&gt;&lt;p&gt;Three ultramafic nodules are texturally and isotopically distinct from the rest of the analyzed nodules. These are friable, have larger&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr ratios, and may represent a deeper sampling of mantle rock than the granulite-facies nodules. They were, however, derived at a shallower depth than the alkalic magma. Thus they are not genetically related to either the magma or the granulite-facies nodules.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1007/BF00382180</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Springer</dc:publisher>
  <dc:title>Strontium isotopic geochemistry of the volcanic rocks and associated megacrysts and inclusions from Ross Island and vicinity, Antarctica</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>