The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS |
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Authors: | PIERRE J Lespérance CHRISTOPHER R Barnes WILLIAM B N Berry ARTHUR J Boucot MU Enzhi |
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Institution: | Département de géAologie, Universitéde Montréal, C.P. 6128, Montréal, Canada H3C 3J7;Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1B 3X5;Department of Paleontology, University of California at Berkeley, Berkeley, California, U.S.A., 94720;Department of Geology, Oregon State University, Corvallis, Oregon, U.S.A. 97331;Nanjing Institute of Geology and Palaeontology, Academia Sinica, Chi-Ming-Ssu, Nanjing, People's Republic of china |
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Abstract: | Lespérance, Pierre J., Barnes, Christopher R., Berry, William B. N., Boucot, Arthur J. & Mu En-zhi 1987 07 15: The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS. The Ordovician-Silurian stratotype at Dob's Linn, Scotland is the second systemic boundary approved by the International Union of Geological Sciences (IUGS). A review of the internationally accepted criteria required of a stratotype shows that few of these are possessed by the Dob's Linn section. The strongest attribute of the section is the presence of zonal graptolites, although the boundary is recognized primarily on a single biological event (base of acuminatus Zone) for which the evolutionary relationships of the taxa are not established. In approving this boundary proposal in 1985, which received only simple majority support within the Ordovician-Silurian Boundary Working Group (OSBWG) and which fails to meet most of the accepted prerequisites for a stratotype, the International Commission on Stratigraphy (ICS) and the IUGS have established an unfortunate precedent. It follows that future systemic boundaries need not meet the accepted standards. It raises serious questions on the assessment and voting procedures of the International Commission on Stratigraphy and on the credence accorded the recommendations developed by the International Subcommission on Stratigraphic Classification of IUGS. |
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Keywords: | Ordovician-Silurian boundary systemic boundary criteria Dob's Linn Scotland biologic events |
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