<html> <head> <meta http-equiv=Content-Type content="text/html; charset=unicode"> <meta name=Generator content="Microsoft Word 12 (filtered)"> <style> <!-- /* Font Definitions */ @font-face {font-family:[SO; panose-1:2 1 6 0 3 1 1 1 1 1;} @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4;} @font-face {font-family:"\@[SO"; panose-1:2 1 6 0 3 1 1 1 1 1;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:12.0pt; font-family:[SO;} h3 {mso-style-link:"h 3 Char"; margin-right:0cm; margin-left:0cm; font-size:13.5pt; font-family:[SO; font-weight:bold;} h4 {mso-style-link:"h 4 Char"; margin-right:0cm; margin-left:0cm; font-size:12.0pt; font-family:[SO; font-weight:bold;} a:link, span.MsoHyperlink {color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline;} p {margin-right:0cm; margin-left:0cm; font-size:12.0pt; font-family:[SO;} span.3Char {mso-style-name:"h 3 Char"; mso-style-link:"h 3"; font-family:[SO; font-weight:bold;} span.4Char {mso-style-name:"h 4 Char"; mso-style-link:"h 4"; font-family:"Cambria","serif"; font-weight:bold;} .MsoChpDefault {font-size:10.0pt;} @page WordSection1 {size:595.3pt 841.9pt; margin:72.0pt 90.0pt 72.0pt 90.0pt;} div.WordSection1 {page:WordSection1;} --> </style> <!-- --> </head> <body lang=ZH-CN link=blue vlink=purple> <div class=WordSection1> <div id=mainContent> <h3><span lang=EN-US style='font-family:"Arial","sans-serif";color:blue'>GSSP for Sinemurian Stage</span></h3> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"; color:red'>&nbsp;</span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif";color:red'>Definition:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif";color:red'>The base of the Sinemurian is exposed in the cliff north of the village of East Quantoxhead, around 6 km east of Watchet, in the administrative district of West Somerset, southwestern England. The boundary level is 0.90 m above the base of Bed 145 coinciding with the first appearance of the genera <i>Vermiceras (V. quantoxense, V. palmeri)</i> and <i>Metophioceras</i> (<i>M.</i> sp. indet. 1). <br> The basal ammonite assemblage of the Sinemurian in the GSSP is earlier than all other assemblages known elsewhere in Europe. In Europe, a stratigraphical gap between both stages is generally present. Correlation with other faunal provinces is possible using the first appearance of <i>Metophioceras</i> s. str. </span></p> <table class=MsoNormalTable border=0 cellpadding=0> <tr> <td style='padding:.75pt .75pt .75pt .75pt'> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Location:</span></h4> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>The &quot;East Quantoxhead&quot; GSSP is situated in the West Somerset administrative district of the county of Somerset (in SW England, about 6km east of the town of Watchet; U.K. National Grid reference ST 137 443. The section is in a coastal cliff 500m north of the Court House, East Quantoxhead, where iron Steps (&quot;Limekiln Steps&quot;) give access to the beach. A footpath (ca. 800m) leads from the car parking near the Court House to the locality. The boundary section is immediately below and on either side of the iron steps. </span></p> </td> <td valign=bottom style='padding:.75pt .75pt .75pt .75pt'></td> </tr> </table> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>&nbsp;</span></p> <table class=MsoNormalTable border=0 cellpadding=0> <tr> <td style='padding:.75pt .75pt .75pt .75pt'> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Sedimentology:</span></h4> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>The boundary section comprises about 27m of strata which include the upper part of the <i>angulata</i> zone and the lower part of the <i>bucklandi</i> zone. This sequence, including the stage boundary, is entirely in Blue Lias facies. The sediments are fine-grained. The Blue Lias typically shows sedimentary cycles which, from the base upwards, comprise: bituminous shale - marl - limestone - marl. </span></p> </td> <td valign=bottom style='padding:.75pt .75pt .75pt .75pt'></td> </tr> </table> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>&nbsp;</span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Primary Markers:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><b><span lang=EN-US style='font-family:"Arial","sans-serif"'>Ammonites:</span></b><span lang=EN-US style='font-family:"Arial","sans-serif"'><br> The boundary level corresponds with the striking change in the ammonite fauna from the genus <i>Schlotheimia</i> (mainly <i>Schlotheimia pseudomoreana</i>) in the latest Hettangian to the genera <i>Vermiceras</i> and <i>Metophioceras</i> in the earliest Sinemurian. The GSSP coincides with the first appearance of the genera <i>Vermiceras quantoxense, Vermiceras palmeri</i> and <i>Metophioceras</i> sp. indet. 1. </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Secondary Markers:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><b><span lang=EN-US style='font-family:"Arial","sans-serif"'>Foraminifera:</span></b><span lang=EN-US style='font-family:"Arial","sans-serif"'><br> <i>Lingulina tenera</i> plex. <i>substriata</i> is characteristic of the latest Hettangian and the consistent appearance of <i>Planularia inaequistriata</i> and the <i>Frondicularia terquemi plexus</i> group is characteristic of the basal Sinemurian. </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Correlation Events:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>Ammonite FAD <i>Vermiceras quantoxense, Vermiceras palmeri</i> </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Notes on Derivation of Age:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>Cycle-scaled linear Sr trend </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>References:</span></h4> <p style='margin-left:36.0pt;text-indent:-36.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'><a href="Sinemurian.pdf">Bloos, G. and Page, K. N., 2002. The Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic). Episodes, 25/1, 22-28.</a></span></p> <p class=MsoNormal><span lang=EN-US><br> <br> <a href="index.html">Back to GSSP Table</a></span></p> </div> </div> <!-- --> </body> </html>