<?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>1405-3322</journal-id>
<journal-title><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></journal-title>
<abbrev-journal-title><![CDATA[Bol. Soc. Geol. Mex]]></abbrev-journal-title>
<issn>1405-3322</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Geológica Mexicana A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-33222020000200007</article-id>
<article-id pub-id-type="doi">10.18268/bsgm2020v72n2a300819</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Paleopalinología y fechamiento por U-Pb en zircones de la Formación El Cien (Oligoceno), Baja California Sur, México]]></article-title>
<article-title xml:lang="en"><![CDATA[Paleopalynology and U-Pb zircon dating of the El Cien Formation (Oligocene), Baja California Sur, Mexico]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Galván-Escobedo]]></surname>
<given-names><![CDATA[Iris G.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[Elia]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Valiente-Banuet]]></surname>
<given-names><![CDATA[Alfonso]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Uscanga-Mortera]]></surname>
<given-names><![CDATA[Ebandro]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Moya]]></surname>
<given-names><![CDATA[Edmundo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Kohashi-Shibata]]></surname>
<given-names><![CDATA[Josué]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Colegio de Postgraduados  ]]></institution>
<addr-line><![CDATA[Texcoco Estado de México]]></addr-line>
<country>México</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Geología Departamento. de Paleontología]]></institution>
<addr-line><![CDATA[CDMX ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Ecología Departamento de Ecología de la Biodiversidad]]></institution>
<addr-line><![CDATA[CDMX ]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2020</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2020</year>
</pub-date>
<volume>72</volume>
<numero>2</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-33222020000200007&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-33222020000200007&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-33222020000200007&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen En las cercanías de San Juan de la Costa, Baja California Sur, se extrajo un barreno (B187) cuyos estratos geológicos corresponden a la Formación El Cien. El fechamiento por el método U-Pb en Zircones indicó que las rocas que conforman dicho barreno se depositaron hace aproximadamente 27.5 millones de años (Oligoceno superior). El estudio paleopalinológico del B187 mostró que en estos estratos se conservan microfósiles (palinomorfos) de origen continental (polen y esporas) y marinos (quistes de dinoflagelados), los cuales fueron cuantificados e identificados. El conjunto total de palinomorfos tuvo una riqueza de 248 taxones, 230 correspondientes a formas continentales y 18 a dinoflagelados. El índice de diversidad &#945; de especies del conjunto total fue de H´= 3.3, con una uniformidad de J´=0.6; los valores de diversidad para el conjunto continental y el de dinoflagelados fueron de H´= 3.6, J´=0.7 y H´= 1.8, J´=0.6, respectivamente. Un análisis de agrupamiento CONISS definió tres palinozonas en la columna estratigráfica del barreno: 1) la palinozona A, que se caracterizó por una pobre riqueza de polen -esporas y dinoflagelados; 2) la palinozona B, que sobresalió por concentrar la mayor riqueza y diversidad de palinomorfos continentales y dinoflagelados, y 3) la palinozona C, que se distinguió por ser la menos productiva en cuanto palinomorfos. Los taxones que dominaron el conjunto continental se asociaron con la presencia de bosque tropical caducifolio tales como Chenopodipollis (Amaranthaceae-Chenopodiaceae), Graminidites (Poaceae), Psilatricolpites (Leguminosae), Liliacidites (Liliaceae, Bromeliaceae y Palmae) y el tipo Stercualiaceae. Por otro lado, algunos otros taxones se consideraron como elementos alóctonos representantes del bosque mesófilo de montaña, como el polen de Eucommia, Fraxinoipollenites (Fraxinus), Betulaceae, Jungladaceae, y diversas esporas entre las que destacó Lusatisporis dettmannae (Selaginella oregana). En el conjunto de dinoflagelados sobresalieron por su abundancia los géneros de Operculodinium y Spiniferites ramosus.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Borehole (B187) near San Juan de la Costa, Baja California Sur, was collected. The strata of this borehole consists of the El Cien Formation. Dating by U-Pb method in Zircons indicated that the sediments were deposited 27.5 million years ago (upper Oligocene). The B187 paleopalynological research shows that in these strata, palynomorphs of both continental (pollen and spores) and marine (dinoflagellate cysts) origin are preserved, which were quantified and identified. The palynomorphs&#8217; richness consists of 248 taxa, 230 were continental and 18 dinoflagellates. The &#945; diversity index of total palinomorphs was H&#8217; = 3.3, with uniformity J&#8217; = 0.6. Values of &#945; diversity for continental and dinoflagellates groups were H&#8217; = 3.6, J´= 0.7 and H&#8217; = 1.8, J´= 0.6, respectively. The CONISS cluster analysis defined three palynozones throughout the borehole stratigraphic column: palynozone A, distinguished by a poor richness of both, pollen-spores and dinoflagellates; in contrast, palynozone B concentrated the highest richness and diversity of continental palinomorphs and dinoflagellates; and palynozone C, had the lowest palinomorphs richness. The assemblage of continental microfossils were dominated by Chenopodipollis (Amaranthaceae-Chenopodiaceae), Graminidites (Poaceae), Psilatricolpites (Leguminosae), Liliacidites (Liliaceae, Bromeliaceae y Palmae) and the Stercualiaceae type, all of which are currently associated with the presence of tropical deciduous forest. On the other hand, pollen of Eucommia, Fraxinoipollenites (Fraxinus), Betulaceae, Jungladaceae, are all allochthonous elements belonging to tropical mountain cloud forests, and diverse spores highlighted by Lusatisporis dettmannae (Selaginella oregana). In the dinoflagellates assemblage, both Operculodinium and Spiniferites ramosus abundance.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[palinomorfos continentales y marinos]]></kwd>
<kwd lng="es"><![CDATA[diversidad de especies]]></kwd>
<kwd lng="es"><![CDATA[bosque tropical caducifolio]]></kwd>
<kwd lng="es"><![CDATA[bosque mesófilo de montaña]]></kwd>
<kwd lng="es"><![CDATA[comparaciones palinoflorísticas]]></kwd>
<kwd lng="en"><![CDATA[continental and marine palynomorphs]]></kwd>
<kwd lng="en"><![CDATA[alpha diversity]]></kwd>
<kwd lng="en"><![CDATA[tropical deciduous forest]]></kwd>
<kwd lng="en"><![CDATA[tropical mountain cloud forests]]></kwd>
<kwd lng="en"><![CDATA[palynomorphic comparisons]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Alatorre]]></surname>
<given-names><![CDATA[A.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Stratigraphy and depositional environments of the phosphorite-bearing Monterrey Formation in Baja California Sur]]></article-title>
<source><![CDATA[Economic Geology]]></source>
<year>1988</year>
<volume>83</volume>
<numero>8</numero>
<issue>8</issue>
<page-range>1918-30</page-range></nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Álvarez-Zuñiga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Sánchez-González]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[López-Mata]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Tejero-Diez]]></surname>
<given-names><![CDATA[J.D.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Composición y abundancia de las pteridofitas en el bosque mesófilo de montaña del municipio de Tlanchinol, Hidalgo, México]]></article-title>
<source><![CDATA[Botanical Sciences]]></source>
<year>2012</year>
<volume>90</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>163-77</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Applegate]]></surname>
<given-names><![CDATA[S.P.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[The El Cien Formation: Strata of Oligocene and early Miocene age in Baja California Sur]]></article-title>
<source><![CDATA[Instituto de Geología, Revista]]></source>
<year>1986</year>
<volume>6</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>145-62</page-range><publisher-name><![CDATA[Universidad Nacional Autónoma de México]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Aranda-Gómez]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Henry]]></surname>
<given-names><![CDATA[C.D.]]></given-names>
</name>
<name>
<surname><![CDATA[Luhr]]></surname>
<given-names><![CDATA[J.F.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Evolución tectonomagmática post-paleocénica de la Sierra Madre Occidental y de la porción meridional de la provincia tectónica de Cuencas y Sierras, México]]></article-title>
<source><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></source>
<year>2000</year>
<volume>53</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>59-71</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Baab]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Blanco y Correa]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[González Flores]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Navarrete Carrillo]]></surname>
<given-names><![CDATA[J.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Téllez Valdés]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[Vega-Aviña]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Serranías de Nayarit]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Toledo-Aceves]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<source><![CDATA[El bosque mesófilo de montaña en México: Amenazas y oportunidades para su conservación y manejo sostenible]]></source>
<year>2010</year>
<page-range>50-9</page-range><publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[Comisión Nacional para el conocimiento y uso de la biodiversidad]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Becerra]]></surname>
<given-names><![CDATA[J.X.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Timing the origin and expansion of the Mexican tropical dry forest]]></article-title>
<source><![CDATA[Proceedings of the National Academy of Sciences of the United States of America]]></source>
<year>2005</year>
<volume>102</volume>
<numero>31</numero>
<issue>31</issue>
<page-range>10919-23</page-range><publisher-name><![CDATA[United States of America, National Academy of Sciences of the United States of America]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Carreño]]></surname>
<given-names><![CDATA[A.L.]]></given-names>
</name>
<name>
<surname><![CDATA[Helenes]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Geology an Ages of the Islands]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Case]]></surname>
<given-names><![CDATA[T.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Cody]]></surname>
<given-names><![CDATA[M. L.]]></given-names>
</name>
<name>
<surname><![CDATA[Ezcurra]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[A new Island Biogeography of the Sea of Cortes]]></source>
<year>2002</year>
<page-range>14-40</page-range><publisher-loc><![CDATA[New York, U.S.A. ]]></publisher-loc>
<publisher-name><![CDATA[Oxford University Press]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Carreño]]></surname>
<given-names><![CDATA[A.L.]]></given-names>
</name>
<name>
<surname><![CDATA[Smith]]></surname>
<given-names><![CDATA[J.T.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Stratigraphy and correlation for the ancient Gulf of California and Baja California Peninsula, México]]></article-title>
<source><![CDATA[Bulletin of American Paleontology]]></source>
<year>2007</year>
<volume>371</volume>
<page-range>1-146</page-range></nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Challenger]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Soberón]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Los Ecosistemas Terrestres]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Soberón]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Halffter]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Llorente-Bosques]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Capital Natural de México: Conocimiento actual de la diversidad]]></source>
<year>2008</year>
<volume>I</volume>
<page-range>87-108</page-range><publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[CONABIO]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Fischer]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Galli-Olivier]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Gidde]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Schwennicke]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[The El Cien Formation of southern Baja California, Mexico]]></article-title>
<source><![CDATA[Stratigraphic precisions, Newsletters on Stratigraphy]]></source>
<year>1995</year>
<volume>32</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>137-61</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Galván-Escobedo]]></surname>
<given-names><![CDATA[I.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Uscanga-Mortera]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Valiente-Banuet]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[García-Moya]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Kohashi-Shibata]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Martínez-Hernández]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Registro Paleopalinológico Preliminar del Barreno B4 de la Formación San Gregorio en Comondú, Baja California Sur, México (resumen en extenso)]]></source>
<year>2012</year>
<conf-name><![CDATA[ Convención Nacional Geológica]]></conf-name>
<conf-date>2012</conf-date>
<conf-loc> </conf-loc>
<publisher-loc><![CDATA[Ciudad de México ]]></publisher-loc>
<publisher-name><![CDATA[Sociedad Geológica Mexicana, A.C.]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Galván-Escobedo]]></surname>
<given-names><![CDATA[I.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Valiente-Banuet]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Helenes-Escamilla]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Paleopalynological comparison of San Gregorio Formation and El Cien Formation, Baja California Sur, Mexico: a preliminary analysis]]></source>
<year>2013</year>
<conf-name><![CDATA[ AASP-Tps 46th Annual Meeting]]></conf-name>
<conf-loc>San Francisco, California, U.S.A. </conf-loc>
<page-range>88-9</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Galván-Escobedo]]></surname>
<given-names><![CDATA[I.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Reyes-Salas]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Martínez-Hernández]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Ángeles-García]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[García-Moya]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Descriptions and botanical affinities of Tubulifloridites Cookson 1947 ex Potonié 1960 pollen grains from the San Gregorio Formation, Baja California Sur, Mexico]]></article-title>
<source><![CDATA[Acta Microscópica]]></source>
<year>2015</year>
<volume>24</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>7-15</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Galván-Escobedo]]></surname>
<given-names><![CDATA[I.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Valiente-Banuet]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Uscanga-Mortera]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[García-Moya]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Kohashi-Shibata]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Registro paleopalinológico de la formación San Gregorio (Barreno B4), Baja California Sur, México]]></article-title>
<source><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></source>
<year>2017</year>
<volume>69</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>35-58</page-range></nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Grimm]]></surname>
<given-names><![CDATA[E.C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[CONISS: a FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares]]></article-title>
<source><![CDATA[Computer &amp; Geosciences]]></source>
<year>1987</year>
<volume>13</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>13-35</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Grimm]]></surname>
<given-names><![CDATA[E.C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Tilia Software. Versión 1.7.16]]></source>
<year>2011</year>
<publisher-loc><![CDATA[Springfield, IL. ]]></publisher-loc>
<publisher-name><![CDATA[Illinois State Museum]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hausback]]></surname>
<given-names><![CDATA[B.P.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cenozoic Volcanic and Tectonic Evolution of Baja California Sur, México]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Frizzell]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geology of the Baja California Peninsula]]></source>
<year>1984</year>
<page-range>219-36</page-range><publisher-loc><![CDATA[Los Angeles, California, U.S.A. ]]></publisher-loc>
<publisher-name><![CDATA[Society of Economic Paleontologists and Mineralogists]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Johnson]]></surname>
<given-names><![CDATA[D.E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Métodos multivariados aplicados al análisis de datos]]></source>
<year>2000</year>
<publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[International Thomson Editores]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kim]]></surname>
<given-names><![CDATA[W.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Barron]]></surname>
<given-names><![CDATA[J.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Diatom biostratigraphy of the upper Oligocene to lowermost Miocene San Gregorio Formation, Baja California Sur, Mexico]]></article-title>
<source><![CDATA[Diatom Research]]></source>
<year>1986</year>
<volume>1</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>169-87</page-range></nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ledesma-Vázquez]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Carreño]]></surname>
<given-names><![CDATA[A.L.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Origin, age, and geological evolution of the Gulf of California]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Brusca]]></surname>
<given-names><![CDATA[R. C.]]></given-names>
</name>
</person-group>
<source><![CDATA[The Gulf of California. Biodiversity and conservation]]></source>
<year>2010</year>
<page-range>7-23</page-range><publisher-loc><![CDATA[Arizona, U.S.A. ]]></publisher-loc>
<publisher-name><![CDATA[The University of Arizona Press and The Arizona-Sonora Desert Museum]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[León de la Luz]]></surname>
<given-names><![CDATA[J.L.]]></given-names>
</name>
<name>
<surname><![CDATA[Domínguez-Cadena]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Mendel-Narváez]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Florística de la Selva Baja Caducifolia de la Península de Baja California, México]]></article-title>
<source><![CDATA[Botanical Sciences]]></source>
<year>2012</year>
<volume>90</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>143-62</page-range></nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[López-Mata]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Villaseñor]]></surname>
<given-names><![CDATA[J.L.]]></given-names>
</name>
<name>
<surname><![CDATA[Cruz-Cárdenas]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Ortíz]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Ortíz-Solorio]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Predictores ambientales de la riqueza de especies de plantas del Bosque Húmedo de Montaña de México]]></article-title>
<source><![CDATA[Botanical Sciences]]></source>
<year>2012</year>
<volume>90</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>27-36</page-range></nlm-citation>
</ref>
<ref id="B23">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Magurran]]></surname>
<given-names><![CDATA[A.E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Diversidad ecológica y su medición]]></source>
<year>1989</year>
<publisher-loc><![CDATA[Barcelona, España ]]></publisher-loc>
<publisher-name><![CDATA[Vedra]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B24">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Martínez-Hernández]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Palinoestratigrafía de la región de Tepexi de Rodríguez, Puebla, México. Implicaciones Cronoestratigráficas]]></article-title>
<source><![CDATA[Revista Mexicana de Ciencias Geológicas]]></source>
<year>1999</year>
<volume>16</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>187-207</page-range></nlm-citation>
</ref>
<ref id="B25">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Martínez-Hernández]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Tertiary Palynofloristic correlations between Mexican Formations with emphasis in dating the Balsas Group]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Vega]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Nyborg]]></surname>
<given-names><![CDATA[T. G.]]></given-names>
</name>
<name>
<surname><![CDATA[Perrilliat]]></surname>
<given-names><![CDATA[M. C.]]></given-names>
</name>
<name>
<surname><![CDATA[Montellano-Ballesteros]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Cevallos-Ferriz]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Quiroz-Barroso]]></surname>
<given-names><![CDATA[S.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Studies on Mexican Paleontology]]></source>
<year>2006</year>
<page-range>19-45</page-range><publisher-loc><![CDATA[Dordrecht, The Netherlands ]]></publisher-loc>
<publisher-name><![CDATA[Springer]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B26">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Miranda]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Hernández-X.]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Los tipos de vegetación de México y su clasificación]]></article-title>
<source><![CDATA[Boletín de la Sociedad Botánica de México]]></source>
<year>1963</year>
<volume>28</volume>
<page-range>29-179</page-range></nlm-citation>
</ref>
<ref id="B27">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Palafox-Silva]]></surname>
<given-names><![CDATA[L.H.]]></given-names>
</name>
</person-group>
<source><![CDATA[Registro palinológico en sedimentos laminados de la cuenca La Paz, Baja California Sur y su relación con cambios paleoceanográficos y paleoclimáticos]]></source>
<year>2013</year>
<publisher-loc><![CDATA[Ensenada, BC, México ]]></publisher-loc>
<publisher-name><![CDATA[Centro de Investigación Científica y de Educación Superior de Ensenada]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B28">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Pielou]]></surname>
<given-names><![CDATA[E.C]]></given-names>
</name>
</person-group>
<source><![CDATA[Ecological Diversity]]></source>
<year>1975</year>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Wiley InterScience]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B29">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ramírez-Arriaga]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Reconstrucción Paleoflorística de la Formación Cuayuca con base en análisis palinoestratigráfico e implicaciones paleogeográficas]]></source>
<year>2005</year>
<publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B30">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rzedowski]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Análisis preliminar de la flora vascular de los bosques mesófilos de montaña de México]]></article-title>
<source><![CDATA[Acta Botánica Mexicana]]></source>
<year>1996</year>
<volume>35</volume>
<page-range>25-44</page-range></nlm-citation>
</ref>
<ref id="B31">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rzedowski]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Vegetación de México]]></source>
<year>2006</year>
<publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[Comisión Nacional para el conocimiento y uso de la biodiversidad]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B32">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rzedowski]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Calderón de Rzedowski]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[El bosque tropical caducifolio de la región mexicana del Bajío]]></article-title>
<source><![CDATA[Trace]]></source>
<year>1987</year>
<volume>12</volume>
<page-range>12-21</page-range></nlm-citation>
</ref>
<ref id="B33">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Seaby]]></surname>
<given-names><![CDATA[R.M.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Henderson]]></surname>
<given-names><![CDATA[P.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Species diversity and richness IV]]></source>
<year>2007</year>
<publisher-loc><![CDATA[Lymington, Hampshire ]]></publisher-loc>
<publisher-name><![CDATA[Pisces Conservation Ltd.]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B34">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Smith]]></surname>
<given-names><![CDATA[J.T.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cenozoic marine mMollusks and paleogeography of the Gulf of California]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Dauphin]]></surname>
<given-names><![CDATA[J.P.]]></given-names>
</name>
<name>
<surname><![CDATA[Simoneit]]></surname>
<given-names><![CDATA[B.R.T.]]></given-names>
</name>
</person-group>
<source><![CDATA[The Gulf and peninsular province of the Californias]]></source>
<year>1991</year>
<page-range>637-66</page-range><publisher-loc><![CDATA[Oklahoma, USA ]]></publisher-loc>
<publisher-name><![CDATA[American Association of Petroleum Geologists in Tulsa]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B35">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Solari]]></surname>
<given-names><![CDATA[L.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Gómez-Tuena]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Bernal]]></surname>
<given-names><![CDATA[J.P.]]></given-names>
</name>
<name>
<surname><![CDATA[Pérez-Arvizu]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[Tanner]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[U-Pb zircon geochronology with an integrated LA-ICP-MS microanalytical workstation: Achievements in Precision and Accuracy]]></article-title>
<source><![CDATA[Geostandards and Geoanalytical Research]]></source>
<year>2010</year>
<volume>34</volume>
<page-range>5-18</page-range></nlm-citation>
</ref>
<ref id="B36">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Srivastava]]></surname>
<given-names><![CDATA[S.K.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Systematic description of some spores from The Edmonton Formation (Maestrichtian), Alberta, Canada]]></article-title>
<source><![CDATA[Palaeontographica, B]]></source>
<year>1972</year>
<volume>139</volume>
<page-range>1-46</page-range></nlm-citation>
</ref>
<ref id="B37">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Traverse]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Paleopalynology]]></source>
<year>2008</year>
<publisher-loc><![CDATA[Netherlands ]]></publisher-loc>
<publisher-name><![CDATA[Springer]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
