<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 Ladinian 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 Ladinian Stage (Middle Triassic) is defined at the base of a 15 - 20cm thick limestone bed overlying a distinctive groove (&quot;Chiesense groove&quot;) of limestone nodules in a shaly matrix, located about 5m above the base of the Buchenstein Beds in the Caffaro River bed (4549'09.5&quot;N, 1028'15.5&quot;E), south of the village of Bagolino (Province of Brescia, Northern Italy). The lower surface of the thick limestone bed has the lowest occurrence of the ammonoid <i>Eoprotrachyceras curionii</i>. Secondary global markers in the uppermost Anisian include the lowest occurrence of conodont <i>Neogondolella praehungarica</i> and a brief normal-polarity magnetic zone recognized in closely correlated sections. The GSSP level is bracketed by U-Pb single zircon age data from volcaniclastic horizons, indicating a boundary age of ca. 241 Ma. </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 at Bagolino (Province of Brescia, Northern Italy) in the eastern Lombardian Alps, in Valle del Caffaro between Val Camonica and Valli Giudicarie. The Anisian/Ladinian boundary succession is well exposed at three sites (A - C) in the bed of the river Caffaro, in the surroundings of the Romanterra Bridge, south of the village of Bagolino. The GSSP Site is situated close to the eastern end of Site B and its coordinates are 614.276 / 5075.118 (UTM-grid) and Long./Lat. 4549'09.5&quot;N, 1028'15.5&quot;E respectively. <br> The GSSP Site (= Site B) is situated approximately 150m ESE of the Romanterra Bridge. </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"'>At Bagolino, the pelagic succession consists from bottom to top of the Angolino Limestone. the Prezzo Limestone, the Buchenstein Beds and the Wengen Beds. <br> The Buchenstein Beds consist of siliceous pelagic nodular limestones and up to a few decimetres thick volcaniclastic layers which can be traced laterally on a regional scale. A marked change in sedimentation is observed at the top of the Buchenstein Beds with the abrupt switch to the predominantly siliciclastic Wengen Beds.<br> The Anisian/Ladinian boundary interval comprises the &quot;transitional beds&quot; and the lower part of the Buchenstein Beds and is best exposed at Sites A - C. In particular, at the eastern end of Site B the fully exposed strata from the 57m-level upward can be traced over several tens of metres along strike.<br> The GSSP level at Bagolino is defined in the lower part of the Buchenstein Beds, around 5m above its base, at the top of a distinct 20-25cm-thick interval of limestone nodules in a shaly matrix in contact (upwards) with several thick limestone beds. </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"'>The GSSP at Bagolino is located at the top of a distinct 20-25cm-thick interval of limestone nodules in a shaly matrix. The Anisian - Ladinian Boundary is defined by the first appearance of the ammonoid genus <i>Eoprotrachyceras</i>, i.e. with the species <i>Eoprotrachyceras curionii</i> at the lower surface of the overlying thick limestone bed. </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"'>Conodonts:</span></b><span lang=EN-US style='font-family:"Arial","sans-serif"'><br> The appearance of <i>Neogondolella praehungarica</i> and its co-occurrence with <i>Paragondolella fueloepi</i> in the upper part of the <i>Neogondolella secedensis</i> zone, just below the GSSP level, seems at present to be the only suitable marker for conodont-based correlations. </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>Eoprotrachyceras curionii</i> (base of the <i>E. curionii</i> zone). Conodont FAD <i>Budurovignathus praehungaricus</i> is in the uppermost Anisian. </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"'>Representatives of the genus <i>Eoprotrachyceras</i> have been reported from numerous places including the Triassic successions in North America (Nevada, British Columbia) and <i>Eoprotrachyceras</i> is therefore a suitable marker for trans-Panthalassan correlation. </span></p> <h4><span lang=EN-US style='font-family:"Arial","sans-serif"'>Notes on Derivation of Age:</span></h4> <p class=MsoNormal><span lang=EN-US style='font-family:"Arial","sans-serif"'>U-Pb array by Mundil et al. on levels near Nevadites (= Secedensis) ammonite zone in Dolomites, plus placement relative to magnetostratigraphy correlations to cycle-scaled Newark magnetic polarity pattern. However, revised correlations and zircon processing suggest 240.5 Ma <br> <br> <b>Outcrop Images:</b><br> <br> <br> <b>Fossils:</b></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="Ladinian.pdf">Brack, P., Rieber, H., Nicora, A., and Mundil, R., 2005. The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale. Episodes 28/4, p. 233-244.</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>