<?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:creator>Wayne A. Roberts</dc:creator>
  <dc:date>1953</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Quartz pods and quartz veins devoid of economic minerals occur&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;the cobalt-copper mineralized&amp;nbsp;&lt;/span&gt;Blackbird&lt;span&gt;&amp;nbsp;&lt;/span&gt;mining&lt;span&gt;&amp;nbsp;&lt;/span&gt;district&lt;span&gt;&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;&lt;/span&gt;Lemhi&lt;span&gt;&amp;nbsp;&lt;/span&gt;County&lt;span&gt;,&amp;nbsp;&lt;/span&gt;Idaho&lt;span&gt;. These barren quartz bodies are found&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;regionally and thermally metamorphosed rocks of the Yellowjacket formation (Belt series) of Pre-cambrian age and are believed to be derived from the enclosing quartz-biotite and quartz-biotite-garnet-chloritoid schists by&amp;nbsp;&lt;/span&gt;metamorphic&lt;span&gt;&amp;nbsp;differentiation. Other rocks that possibly are products of&amp;nbsp;&lt;/span&gt;metamorphic&lt;span&gt;&amp;nbsp;differentiation are discussed. Two zones of regional metamorphism are recognized, a biotite zone and a garnet zone. Contact metamorphism associated with the granitic intrusive rocks of the&amp;nbsp;&lt;/span&gt;Idaho&lt;span&gt;&amp;nbsp;batholith is recognized adjacent to the batholith.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.2113/gsecongeo.48.6.447</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Society of Economic Geologists</dc:publisher>
  <dc:title>Metamorphic differentiates in the blackbird mining district, Lemhi County, Idaho</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>