<?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>F.T. Manheim</dc:contributor>
  <dc:contributor>P.R. Betzer</dc:contributor>
  <dc:creator>D.W. Eggimann</dc:creator>
  <dc:date>1980</dc:date>
  <dc:description>&lt;div&gt;&lt;div id="12457793" class="article-section-wrapper js-article-section js-content-section  " data-section-parent-id="0"&gt;&lt;p&gt;The analytical estimation of amorphous silica in selected Atlantic and Antarctic Ocean sediments, the U.S.G.S. standard marine mud (MAG-1), A.A.P.G. clays, and samples from cultures of a marine diatom, Hemidiscus, has been examined. Quantitative recovery of sedimentary amorphous silica was achieved by reacting 2 M Na&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;CO&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;with a sample for 4 hours at 90 degrees -100 degrees C; where necessary, aluminum analysis is used to correct for the extraction of non-amorphous silica. Oceanic sediments having an amorphous SiO&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;/clay ratio of 1.0 or more can be analyzed by a single extraction with 2 M Na&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;CO&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;, without correction for non-amorphous additions. Marine sediments having an amorphous SiO&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;/clay ratio of from 1.0 to 0.25 can be corrected for inputs of clay-derived silica using an aluminum determination and an empirical correction factor. Sediments with amorphous SiO&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;/clay ratios of less than 0.25, samples containing non-silica-bearing aluminous materials such as gibbsite, or materials having low absolute levels of amorphous silica require successive leaches to accurately correct for silica inputs from non-amorphous sources. Our values for amorphous silica-rich circum-Antarctic sediments are equal to or greater than literature values, whereas our values for a set of amorphous silica-poor sediments from a transect of the North Atlantic at 11 degrees N, after appropriate correction for silica released from clays, are significantly lower than previous estimates from the same region.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1306/212F79AF-2B24-11D7-8648000102C1865D</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>SEPM</dc:publisher>
  <dc:title>Dissolution and analysis of amorphous silica in marine sediments</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>