<?xml version="1.0"?>
<!DOCTYPE article SYSTEM "journalpublishing.dtd">
<article article-type="research-article">
<front>
<journal-meta>
<journal-id journal-id-type="archive">gsminmag</journal-id>
<journal-title>Mineralogical Magazine</journal-title>
<abbrev-journal-title abbrev-type="full">Mineralogical Magazine</abbrev-journal-title>
<issn pub-type="ppub">0026-461X</issn>
<publisher>
<publisher-name>Mineralogical Society</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.1180/minmag.1994.058.391.12</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Mineralogy</subject>
</subj-group>
</article-categories>
<title-group>
<article-title>Formation of Chlor- and Fluor-Apatite Layered Intrusions</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>Grant Cawthorn</surname>
<given-names>R.</given-names>
</name>
<aff>Department of Geology, University of the Witwatersrand, Private Bag 3, PO Wits 2050, Republic of South Africa</aff></contrib></contrib-group>
<pub-date pub-type="ppub">
<month>6</month>
<year>1994</year>
</pub-date>
<volume>58</volume>
<issue>391</issue>
<fpage>299</fpage>
<lpage>306</lpage>
<history>
<date date-type="received">
<day>15</day>
<month>2</month>
<year>1993</year>
</date>
<date date-type="rev-recd">
<day>23</day>
<month>8</month>
<year>1993</year>
</date></history>
<copyright-statement>Copyright &#x00A9; 1994, The Mineralogical Society</copyright-statement>
<copyright-year>1994</copyright-year>
<abstract>
<title>Abstract</title>
<p>Apatite in most igneous intrusions has a high Cl/F ratio. However, chlor-apatite has been reported in the lower portions of the Bushveld and Stillwater Complexes. This has been used as evidence supporting the early separation of a Cl-rich discrete hydrous fluid in these intrusions. Mineralogical evidence is presented here to demonstrate that the Bushveld Complex, at least, formed from a nearly anhydrous magma, and did not release a hydrous fluid before apatite began to crystallize. It is suggested that apatite in the earliest cumulates equilibrated with trapped interstitial liquid, which converted it from the typical F-rich composition of cumulus apatite to a Cl-rich composition. This is an analogous process to that in which cumulus mafic minerals may become more Fe-rich on cooling and reaction with interstitial liquid.</p></abstract>
<kwd-group>
<title>Keywords</title>
<kwd>apatite</kwd>
<kwd>layered intrusions</kwd>
<kwd>Cl/F ratio</kwd>
<kwd>Bushveld Complex</kwd>
</kwd-group>
</article-meta>
</front>
</article>
