<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:Wingdings; panose-1:5 0 0 0 0 0 0 0 0 0;} @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;} /* List Definitions */ ol {margin-bottom:0cm;} ul {margin-bottom:0cm;} --> </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 Danian 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 Cenozoic Era, Paleogene System, Paleocene Series and Danian Stage is defined at the reddish layer at the base of the 50cm thick, dark boundary clay in a tributary of the Oued Djerfane, west of El Kef, Tunisia, where it coincides with the Iridium Anomaly fallout from a major asteroid impact. </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 GSSP is located in northern Tunisia about 7km west of the town of El Kef. The locality is reached by taking the road to Tajerouine for about 5km and then turning onto an unpaved road leading to the village of Hamman Mellgue. The GSSP section is located at 3km from the road sign to Hamman Mellgue between a small village and a recent artificial lake. The GSSP is reached after descending into this valley for about 1.5km. The GSSP is located at a latitude of 3609'13.2&quot;N and a longitude of 838'54.8&quot;E. </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 El Haria Formation at El Kef consists of: </span></p> <ul type=disc> <li class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>90m of glauconitic and phosphated marl and marly limestone </span></li> <li class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>310m of brownish to dark clay </span></li> <li class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>65m of gray marl with fine interbedded limestone </span></li> <li class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>200m of dark clay and marls containing the Cretaceous - Paleogene Boundary </span></li> <li class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>lower interbedded marl and limestone </span></li> </ul> </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'><span lang=EN-US style='font-family:"Arial","sans-serif"'>The GSSP is defined at the base of the boundary clay. It is overlain by a rusty red layer containing a peak of Ni-rich spinel, which is more concentrated than the iridium anomaly. This implies that all the sediments generated by the meteorite impact belong to the Danian. This millimeter thick layer, containing the evidence of the meteorite impact and other significant geochemical changes, coincides with a sudden catastrophic mass extinction event. </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> The first appearance of Paleogene foraminifera occurs at the base or within a few centimeters of the boundary clay, for example FAD of <i>Globoconusa conusa</i>.<br> <b>Stable Isotopes:</b><br> A negative <sup>13</sup>C shift is found in marine calcareous plankton of low and middle latitudes (fine fraction or planktonic foraminifera). </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"'>Iridium geochemical anomaly. Associated with a major extinction horizon (dinosaurs, ammonites, foraminifers, etc.) </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"'>Ar-Ar age suite. However, U-Pb ages are reported to be slightly older than 66 Ma </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="Danian.pdf">Molina, E., Alegret, L., Arenillas, I., Arz, J. A., Gallala, N., Hardenbol, J., von Salis, K., Steurbaut, E., Vandenberghe, N, and Zaghbib-Turki, D. 2006. The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, &quot;Tertiary&quot;, Cenozoic) at El Kef, Tunisia: original definition and revision. Episodes 29/4, p. 263 - 278.</a></span></p> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>&nbsp;</span></p> <p style='margin-left:36.0pt;text-indent:-36.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>Keller, G., Li, L., and MacLeod, N., 1995. The Cretaceous/Tertiary boundary stratotype section at El Kef, Tunisia: how catastrophic was the mass extinction? Paleogeography, Paleoclimatology, Palaeoecology 119, p. 221 - 254.</span></p> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>&nbsp;</span></p> <p style='margin-left:36.0pt;text-indent:-36.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>Bensalem, H., 2002. The Cretaceous-Paleogene transition in Tunisia: general overview. Paleogeography, Paleoclimatology, Palaeoecology 178, p. 139 - 143.</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>