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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>J. J. Papike</dc:contributor>
  <dc:contributor>S.B. Simon</dc:contributor>
  <dc:contributor>J.C. Laul</dc:contributor>
  <dc:contributor>R.P. Christian</dc:contributor>
  <dc:creator>C.K. Shearer</dc:creator>
  <dc:date>1984</dc:date>
  <dc:description>&lt;p&gt;Interaction between country rock and fluids derived from the Tip Top pegmatite has resulted in a series of boron enriched assemblages. Between unaltered quartz-mica schist to the pegmatite contact is a succession of four mineral assemblages:&lt;/p&gt;&lt;ul class="list"&gt;&lt;li class="react-xocs-list-item"&gt;&lt;span class="list-label"&gt;1.&lt;/span&gt;&lt;p&gt;(1) Quartz-Biotite-Potassium Feldspar assemblage (Q-B-K), which consists essentially of the original metamorphic silicate assemblage plus anomalously high amounts of modal tourmaline&lt;/p&gt;&lt;/li&gt;&lt;li class="react-xocs-list-item"&gt;&lt;span class="list-label"&gt;2.&lt;/span&gt;&lt;p&gt;(2) Quartz-Biotite-Tourmaline assemblage (Q-B-T)&lt;/p&gt;&lt;/li&gt;&lt;li class="react-xocs-list-item"&gt;&lt;span class="list-label"&gt;3.&lt;/span&gt;&lt;p&gt;(3) Tourmaline-Quartz-Muscovite assemblage (T-Q-M)&lt;/p&gt;&lt;/li&gt;&lt;li class="react-xocs-list-item"&gt;&lt;span class="list-label"&gt;4.&lt;/span&gt;&lt;p&gt;(4) Tourmaline-Quartz assemblage (T-Q). Alkali elements (Cs, Rb, K, Li), SiO&lt;sub&gt;2&lt;/sub&gt;, and Ba show a decrease from the Q-B-K assemblage to the T-Q assemblage. A1&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, Ga, B, total Fe and Zn increase moderately from the Q-B-K assemblage to the T-Q assemblage.&lt;/p&gt;&lt;/li&gt;&lt;/ul&gt;&lt;p&gt;The mineral chemistries also change considerably. The Mg/(Mg + Fe&lt;sup&gt;2+&lt;/sup&gt;) ratios in biotites range from 0.54 to 0.50 in samples from the Q-B-K assemblage to 0.39 in the (Q-B-T) assemblage. The range in tourmaline end-member components from the Q-B-K assemblage to the T-Q assemblage is as follows: Q-B-K: Dravite&lt;sub&gt;.63&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Schorl&lt;sub&gt;.23&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Elbaite&lt;sub&gt;.05&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Buergerite&lt;sub&gt;.09&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;T-Q: Dravite&lt;sub&gt;.23&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Schorl&lt;sub&gt;.37&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Elbaite&lt;sub&gt;.17&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Buergerite&lt;sub&gt;.23&lt;/sub&gt;.&lt;/p&gt;&lt;p&gt;Observed variations in mineral assemblage and whole rock chemistry within the alteration zone appear to a first approximation to be a function of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;μB&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;i&gt;O&lt;/i&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(boron metasomatism) and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;μK&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;i&gt;O&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(alkali leaching). The breakdown of feldspar and biotite may be approximated by reactions: 2HCl + 2(K, Na)AlSi&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;/ai 2(K, Na)Cl + Al&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;5&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;+ 5SiO&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;+ H&lt;sub&gt;2&lt;/sub&gt;O and 2 Annite + SiO&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;+ 5Al&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;5&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;+ 2NaCl + 6H&lt;sub&gt;3&lt;/sub&gt;BO&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;/ai 2 Tourmaline + 2KCl + 7H&lt;sub&gt;2&lt;/sub&gt;O.&lt;/p&gt;&lt;p&gt;The alteration zone may represent either a single episode (B-, Cs-, Li-, Rb-enriched fluid) or multiple episodes (B, Zn, Mn fluid and Cs, Li, Rb fluid) of pegmatite fluid-schist interactions. In both situations, B in the aqueous fluid from the pegmatite reacts with the schist breaking down sheet silicate “traps” for Cs, Rb, Li, and K and forming tourmaline-rich assemblages.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0016-7037(84)90306-5</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Pegmatite/wallrock interactions, Black Hills, South Dakota: Progressive boron metasomatism adjacent to the Tip Top pegmatite</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>