<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 Induan 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 Mesozoic Era, Triassic System and Induan Stage is defined at the base of Bed 27c in the Meishan Section, Changxing County, Zhejiang Province, China. It coincides with the first occurrence of the conodont species <i>Hindeodus parvus</i> in the evolutionary lineage <i>Hindeodus latidentatus - Hindeodus parvus - Isarcicella isarcica</i>. </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"'>Base of Bed 27c at the Meishan Section, Changxing County, Zhejiang Province, China. The longitude and latitude of the section are 11942&quot;20.9 E and 314&quot;47.28 N respectively. </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 strata of Bed 24 consist of dark-gray medium-bedded wacke- and packstones. Bed 25, &quot;White Clay&quot; is a light bluish grey illite-montmorillonite claystone. Bed 26 &quot;Black Clay&quot; is a dark grey montmorillonite-illite claystone. The GSSP Bed 27 consists of a light grey medium-bedded silty limestone, overlayed by grayish clay and medium-bedded dolomitic, argillaceous calcimicrite (Beds 28, 29). </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'><span lang=EN-US style='font-family:"Arial","sans-serif"'>First occurrence of the conodont species <i>Hindeodus parvus</i> in the evolutionary lineage <i>Hindeodus latidentatus - Hindeodus parvus - Isarcicella isarcica</i> at the base of Bed 27c in the Meishan Section </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"'>Radiometric Dating:</span></b><span lang=EN-US style='font-family:"Arial","sans-serif"'><br> Zircon dating of the &quot;White Clay&quot; (Bed 25) using SHRIMP (ion-microprobe) dating gave a <sup>206</sup>PB/<sup>238</sup>U age of 251.2 3.4 Ma.<br> Using incremental-heating <sup>40</sup>Ar/<sup>39</sup>Ar analysis of sanidine grains (100-150</span><span lang=EN-US style='font-family:Symbol'>m</span><span lang=EN-US style='font-family:"Arial","sans-serif"'> across) extracted from the &quot;White Clay&quot;, obtained a plateau date of 249.91 0.15 Ma, and a mean date by individual total-fusion analyses of 249.62Ma. The top of the &quot;White Clay&quot; is 0.14m below the level at which the GSSP is proposed, hence an unknown, but probably small number of years should be subtracted from the above determinations in order to approximate the age of the basal Triassic.<br> <b>Stable Carbon Isotopes:</b><br> <sup>13</sup>C and <sup>18</sup>O minima (-1.90 and -8.30 , respectively have been shown in the lower part of Bed 27, dropping from highs in beds below of +2.5 - 3.50 . A similarly abrupt drop in <sup>13</sup>C within the Permian-Triassic Boundary interval has been detected elsewhere in South China, throughout the Tethyan region and in Greenland. </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"'>Conodont FAD <i>Hindeodus parvus</i> </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Other Locations around the World:</span></h4> <p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>The evolutionary lineage <i>Hindeodus latidentatus - Hindeodus parvus - Isarcicella isarcica</i> has been recognized in Iran, the Salt Range, and at the Gartnerkofel in the Carnic Alps. </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"'>Average of U-Pb constraints from Bowring et al. (1998). However, revised processing for U-Pb ages suggest 252.5 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="Induan.pdf">Yin, H., Zhang, K., Tong, J., Yang, Z.i, and Wu, S., 2001. The Global Stratotype Section and Point (GSSP) of the Permian - Triassic Boundary. Episodes 24/2, p. 102 - 114.</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"'>Yin, H., Sweet, W. C., Glenister, B. F., Kotlyar, G., Kozur, H., Newell, N. D., Sheng, J., Yang, Z., and Zakharov, Y. D., 1996. Recommendation of the Meishan Section as Global Stratotype Section and Point for basal boundary of Triassic System. Newsl. Stratigr. 34/2, p. 81 - 108.</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"'>Yin, H. (ed.), 1996: The Paleozoic-Mesozoic boundary, candidates of Global Stratotype Section and Point of the Permian-Triassic Boundary. China University of Geosciences Press, Wuhan, 137pp.</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>