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Achondrite
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<h2 id="classification">Classification</h2> <p>Achondrites are classified into the following groups:<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p> <ul><li><a href="/facts/Primitive_achondrite/wWCJmm2y">Primitive achondrites</a></li> <li><a href="/facts/Asteroidal_achondrite/X3xuMvue">Asteroidal achondrites</a></li> <li><a href="/facts/Lunar_meteorite/gpq02Hsf">Lunar meteorites</a></li> <li><a href="/facts/Martian_meteorite/kp9vW6RM">Martian meteorites</a></li></ul> <h3>Primitive achondrites</h3> <p>Primitive achondrites, also called PAC group, are so-called because their chemical composition is <i><a href="/facts/Primitive_rock/h7sogSGV">primitive</a></i> in the sense that it is similar to the composition of <a href="/facts/Chondrites/mbzbGm5A">chondrites</a>, but their texture is igneous, indicative of melting processes. To this group belong:<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p> <ul><li><a href="/facts/Acapulcoite/L0MRQjoA">Acapulcoites</a> (after the meteorite Acapulco, Mexico)</li> <li><a href="/facts/Lodranite/D7dqMPd7">Lodranites</a> (after the meteorite Lodran)</li> <li><a href="/facts/Winonaite/31VDbqP4">Winonaites</a> (after the meteorite Winona)</li> <li><a href="/facts/Ureilite/nv8UN6qp">Ureilites</a> (after the meteorite Novy Ureii, Russia)</li> <li><a href="/facts/Brachinite/NqgvGVUo">Brachinites</a> (after the meteorite Brachina)</li></ul> <h3>Asteroidal achondrites</h3> <p>Asteroidal achondrites, also called evolved achondrites, are so-called because they have been <i>differentiated</i> on a <a href="/facts/Parent_body/RjbNc3gv">parent body</a>. This means that their mineralogical and chemical composition was changed by melting and crystallization processes. They are divided into several groups:<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <ul><li><a href="/facts/HED_meteorite/5W2K84zC">HED meteorites</a> (Vesta). They may have originated on the asteroid <a href="/facts/Vesta_(asteroid)/xnQ8acw1">4 Vesta</a>, because their reflection spectra are very similar.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> They are named after the initial letters of the three subgroups: <ul><li><a href="/facts/Howardite/lcP3D6X6">Howardites</a></li> <li><a href="/facts/Eucrite/M311uJ40">Eucrites</a></li> <li><a href="/facts/Diogenite/LlHwPNDe">Diogenites</a></li></ul></li> <li><a href="/facts/Angrite/T8R45MAr">Angrites</a></li> <li><a href="/facts/Aubrite/xxw1pdAe">Aubrites</a></li></ul> <h3>Lunar meteorites</h3> <p><a href="/facts/Lunar_meteorites/gpq02Hsf">Lunar meteorites</a> are meteorites that originated from the <a href="/facts/Moon/zKHqEMPb">Moon</a>. </p> <h3>Martian meteorite</h3> <p><a href="/facts/Martian_meteorite/kp9vW6RM">Martian meteorites</a><a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> are meteorites that originated from <a href="/facts/Mars/AQGtVvz0">Mars</a>. They are divided into three main groups, with two exceptions (see last two entries): </p> <ul><li><a href="/facts/Shergottite/kp9vW6RM">Shergottites</a></li> <li><a href="/facts/Nakhlite/oaRMCVsd">Nakhlites</a></li> <li><a href="/facts/Chassignite/kp9vW6RM">Chassignites</a></li> <li><a href="/facts/OPX_martian_meteorites/kp9vW6RM">OPX martian meteorites</a> (<a href="/facts/Allan_Hills_84001/dJvGy3cv">ALH 84001</a>)</li> <li>Regolith/Soil samples (<a href="/facts/Northwest_Africa_7034/uI4b0zQl">NWA 7034 and pairings</a>)</li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Glossary_of_meteoritics/TbTPV1Ut">Glossary of meteoritics</a></li></ul> <h2 id="external-links">External links</h2> Wikimedia Commons has media related to Achondrite meteorites. <ul><li><a href="http://www.meteorites.com.au/collection/achondrites.html">Achondrite Images</a> from Meteorites Australia</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Etymology: from the prefix a- (privative a) and the word chondrite. <a href="/wiki/Privative_a" target="_blank">/wiki/Privative_a</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Recommended classifications: Eucrite-pmict <a href="http://www.lpi.usra.edu/meteor/metbullclass.php?sea=Eucrite-pmict" target="_blank">http://www.lpi.usra.edu/meteor/metbullclass.php?sea=Eucrite-pmict</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Achondrite, Encyclopædia Britannica <a href="http://www.britannica.com/EBchecked/topic/3630/achondrite" target="_blank">http://www.britannica.com/EBchecked/topic/3630/achondrite</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Sahijpal, S.; Soni, P.; Gagan, G. (2007). "Numerical simulations of the differentiation of accreting planetesimals with 26Al and 60Fe as the heat sources". Meteoritics & Planetary Science. 42 (9): 1529–1548. Bibcode:2007M&PS...42.1529S. doi:10.1111/j.1945-5100.2007.tb00589.x. <a href="https://doi.org/10.1111%2Fj.1945-5100.2007.tb00589.x" target="_blank">https://doi.org/10.1111%2Fj.1945-5100.2007.tb00589.x</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Gupta, G.; Sahijpal, S. (2010). "Differentiation of Vesta and the parent bodies of other achondrites". J. Geophys. Res. Planets. 115 (E8). Bibcode:2010JGRE..115.8001G. doi:10.1029/2009JE003525. S2CID 129905814. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Mason, B. (1962). Meteorites. New York: John Wiley. <a href="https://archive.org/details/meteorites0000maso" target="_blank">https://archive.org/details/meteorites0000maso</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Mittlefehldt, David W.; McCoy, Timothy J.; Goodrich, Cyrena Anne; Kracher, Alfred (1998). "Non-chondritic Meteorites from Asteroidal Bodies". Reviews in Mineralogy and Geochemistry. 36 (1): 4.1 – 4.195. <a href="http://rimg.geoscienceworld.org/cgi/content/abstract/36/1/4.1" target="_blank">http://rimg.geoscienceworld.org/cgi/content/abstract/36/1/4.1</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>O. Richard Norton. The Cambridge encyclopedia of meteorites. UK, Cambridge University Press, 2002. ISBN 0-521-62143-7. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>O. Richard Norton. The Cambridge encyclopedia of meteorites. UK, Cambridge University Press, 2002. ISBN 0-521-62143-7. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>O. Richard Norton. The Cambridge encyclopedia of meteorites. UK, Cambridge University Press, 2002. ISBN 0-521-62143-7. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Drake, M. J. (2001). "The eucrite/Vesta story". Meteoritics and Planetary Science. 36 (4): 501–513. Bibcode:2001M&PS...36..501D. doi:10.1111/j.1945-5100.2001.tb01892.x. S2CID 128394153. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Treiman, A. H. (2000). "The SNC meteorites are from Mars". Planetary and Space Science. 48 (12–14): 1213–1230. Bibcode:2000P&SS...48.1213T. doi:10.1016/S0032-0633(00)00105-7. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> </ol>