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<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.1997.061.408.09</article-id>
<title-group>
<article-title>Igneous Graphite in Enstatite Chondrites</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>Rubin</surname>
<given-names>Alan E.</given-names>
</name>
<aff>Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA</aff></contrib></contrib-group>
<pub-date pub-type="ppub">
<month>10</month>
<year>1997</year>
</pub-date>
<volume>61</volume>
<issue>408</issue>
<fpage>699</fpage>
<lpage>703</lpage>
<history>
<date date-type="received">
<day>5</day>
<month>6</month>
<year>1996</year>
</date>
<date date-type="rev-recd">
<day>23</day>
<month>1</month>
<year>1997</year>
</date></history>
<copyright-statement>Copyright &#x00A9; 1997, The Mineralogical Society</copyright-statement>
<copyright-year>1997</copyright-year>
<abstract>
<title>Abstract</title>
<p>Igneous graphite, a rare constituent in terrestrial mafic and ultramafic rocks, occurs in three EH and one EL enstatite chondrite impact-melt breccias as 2&#x2013;150 &#x00B5;m long euhedral laths, some with pyramidal terminations. In contrast, graphite in most enstatite chondrites exsolved from metallic Fe-Ni as polygonal, rounded or irregular aggregates. Literature data for five EH chondrites on C combusting at high temperatures show that Abee contains the most homogeneous C isotopes (i.e. &#x03B4;<sup>13</sup>C = &#x2212;8.1 &#x00B1; 2.1&#x2030;); in addition, Abee's mean &#x03B4;<sup>13</sup>C value is the same as the average high-temperature C value for the set of five EH chondrites. This suggests that Abee scavenged C from a plurality of sources on its parent body and homogenized the C during a large-scale melting event. Whereas igneous graphite in terrestrial rocks typically forms at relatively high pressure and only moderately low oxygen fugacity (e.g., &#x223C; 5 kbar, log<italic>f</italic><sub>O<sub>2</sub></sub> &#x223C; &#x2212;10 at 1200&#x00B0;C), igneous graphite in asteroidal meteorites formed at much lower pressures and oxygen fugacities.</p></abstract>
<kwd-group>
<title>Keywords</title>
<kwd>igneous graphite</kwd>
<kwd>enstatite chondrite</kwd>
<kwd>impact-melt breccia</kwd>
<kwd>oxygen fugacity</kwd>
</kwd-group>
</article-meta>
</front>
</article>
