<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1026-8774</journal-id>
<journal-title><![CDATA[Revista mexicana de ciencias geológicas]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. cienc. geol]]></abbrev-journal-title>
<issn>1026-8774</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Geología]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1026-87742019000100054</article-id>
<article-id pub-id-type="doi">10.22201/cgeo.20072902e.2019.1.928</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Escleritomos de Chancelloria eros y escleritos del Cámbrico medio (Serie 3, Piso 5) de Sonora central, México]]></article-title>
<article-title xml:lang="en"><![CDATA[Scleritomes of Chancelloria eros and sclerits from the middle Cambrian (Series 3, Stage 5) of central Sonora, Mexico]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[Matilde S.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[Blanca]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[Francisco J.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Palafox]]></surname>
<given-names><![CDATA[Juan J.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Consejo Nacional de Investigaciones Científicas y Tecnológicas  ]]></institution>
<addr-line><![CDATA[Mendoza ]]></addr-line>
<country>Argentina</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Geología Departamento de Paleontología]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad de Sonora División de Ciencias Exactas y Naturales Departamento de Geología]]></institution>
<addr-line><![CDATA[Hermosillo Sonora]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2019</year>
</pub-date>
<volume>36</volume>
<numero>1</numero>
<fpage>54</fpage>
<lpage>63</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1026-87742019000100054&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1026-87742019000100054&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1026-87742019000100054&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN Fragmentos de escleritomos de Chancelloria eros del Cámbrico medio de Sonora, México se registran por primera vez. Escleritomos de chancellóridos parcialmente articulados y escleritos aislados pertenecientes a Allonnia tintinopsis y Archiasterella sp. se encuentran ampliamente distribuidos en calcilutitas rojizas de la Formación El Gavilán, en la sección del Sahuaral, Sonora central. La fauna está compuesta por chancellóridos, braquiópodos linguliformes, espículas de esponjas reticulosas, trilobites y hyolítidos. La Formación El Gavilán es una secuencia de plataforma abierta de 65 m de espesor, compuesta de calcilutita intercalada con caliza margosa de estratificación delgada. La asociación de trilobites permitió asignar el depósito al Cámbrico medio, Subzona de Altiocculus, Zona de Ehmaniella (Serie 3, Piso 5). Los géneros de chancellóridos de la sección de El Sahuaral pueden ser comparados con la biota de San José de Gracia, Sonora central, México y también con depósitos cámbricos de la plataforma alrededor de Laurentia como son Burgess Shale en Canadá y formaciones de Utah en EUA. Las rocas del Cámbrico de Sonora fueron parte de la periferia suroeste del cratón de Laurentia, la cual se ubicaba cerca del paleo-ecuador durante el Cámbrico.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[ABSTRACT Fragments of scleritomes of Chancelloria eros from the middle Cambrian of Sonora, Mexico are reported for the first time. Chancelloriid scleritomes partially articulated and isolated sclerites belonging to Allonnia tintinopsis and Archiasterella sp. are widely distributed in reddish calcilutite of the El Gavilán Formation, in the Sahuaral section, central Sonora. The faunal association is represented by chancelloriids, spicules of reticulosan sponges, linguliform brachiopods, hyoliths and trilobites. The El Gavilán Formation is an open shelf sequence of 65 m thick, composed of calcilutite interbedded with thin-bedded marly limestone. Trilobite association allowed assigning the open shelf deposit to the middle Cambrian, Altiocculus Subzone, Ehmaniella Zone (Series 3, Stage 5). Chancelloriid genera of the El Sahuaral section may be compared with the biota of San Jose de Gracia, in central Sonora, México, and also with other mid-Cambrian shelf deposits around Laurentia as Burgess Shale in Canada and formations from Utah, USA. Cambrian rocks of Sonora were part of the southern-western border of Laurentia craton, which was located near the paleo-equator during Cambrian times.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Chancelloria eros]]></kwd>
<kwd lng="es"><![CDATA[Allonnia]]></kwd>
<kwd lng="es"><![CDATA[Archiasterella]]></kwd>
<kwd lng="es"><![CDATA[Altiocculus Subzona]]></kwd>
<kwd lng="es"><![CDATA[Cámbrico medio]]></kwd>
<kwd lng="es"><![CDATA[Sonora]]></kwd>
<kwd lng="es"><![CDATA[México]]></kwd>
<kwd lng="en"><![CDATA[Chancelloria eros]]></kwd>
<kwd lng="en"><![CDATA[Allonnia]]></kwd>
<kwd lng="en"><![CDATA[Archiasterella]]></kwd>
<kwd lng="en"><![CDATA[Altiocculus Subzone]]></kwd>
<kwd lng="en"><![CDATA[middle Cambrian]]></kwd>
<kwd lng="en"><![CDATA[Sonora]]></kwd>
<kwd lng="en"><![CDATA[Mexico]]></kwd>
</kwd-group>
</article-meta>
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