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The AAPG/Datapages Combined Publications Database
CSPG Bulletin
Abstract
International Permian-Triassic Conference, August 23-26, 1971, Calgary, Alberta
The Permian-Triassic Boundary in New Zealand and New Caledonia and Its Relationship to World Climatic Changes and Extinction of Permian Life [Abstract]
In New Zealand the stratigraphic contact between Triassic and Permian seems to be gradational locally, but there is no faunal intergradation, and it appears possible that basal Triassic faunas are not present. The Permian segment is unusually thick, almost entirely marine, and moderately fossiliferous. The penultimate faunas, characteristic of the Waiitian Stage, are normal Permian faunas, approximately equivalent to the Dzhulfian of Armenia, found also in Iran, Salt Range, Wuchiaping (China), Japan (Gujo), and perhaps the Kalouzin Suite of east Siberia (Licharew, 1966), though the latter may be as old as Ufimian. The uppermost Permian fauna, characteristic of the Makarewan Stage, has been correlated with the Paratirolites faunas of Armenia and south China (Changsing), but unlike these faunas, lacks any of the major brachiopod groups, such as Orthotetida or Productida, which virtually disappeared at the end of the Paleozoic Era. The brachiopod genera are members of superfamilies which survived into the Triassic, such as Rhynchonellacea, Spiriferacea and Dielasmatacea, but the genera are characteristic of the Permian Period. It is thus possible that the Makarewan Stage represents the very latest Permian, and the most convincing transition yet known into Triassic.
The earliest Triassic in New Zealand contains poorly dated bivalves. The earliest ammonoids are of Middle Scythian, or Smithian age.
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The contact between Prmian and Triassic in New Caledonia is less well exposed, and falls somewhere between brachiopods and bivalves of Capitanian (=basal Tatarian) age, equivalent to the Puruhauan Stage of New Zealand, and Ladinian brachiopods. Ammonoids, including xenodiscids, have been described by Avias and Guerin as either Late Permian or Early Triassic. Some belong to Cyclobus and Xenaspis of Middle Permian (Capitanian) age.
The sequence of Permian faunas in New Zealand provides a key to the nature of the Permian-Triassic contact. The faunas alternate in composition and affinities. Three faunas in the sequence of eight are relatively impoverished generically, with strong affinities to faunas of eastern Australia, and coincide in age with the main glacial phases of the east Australian Permian. Overlying faunas are more diversified, and therefore indicative of relatively warmer water. Following faunas are very diverse, and include fusulinacea and reef-building corals, absent from the other suites. Each warm-water fauna is followed by an abrupt faunal change to a cool-water fauna.
This pattern of three cold episodes followed by warmer intervals is also reflected widely by faunas in the Northern Hemisphere through Canada and Siberia, and the cold episodes even affected paleotropical regions such as Texas, when cold-water genera such as Yakovlevia and Spiriferella were introduced for brief times. The pattern of glaciation and amelioration is also reflected in an intricate way by the nature of sedimentation, particularly in the formation of coral reefs, coal measures, tillites, salt deposits and red beds over the entire globe.
Furthermore, climatic changes provide a simple explanation for the great destruction of life at the end of the Permian Period. This is considered to have been real, affecting over 50 per cent of all life. Faunal analyses show that the genera and families which perished were essentially tropical in hibitat, and that a prime cause lay in unusually high temperatures for a brief interval.
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ACKNOWLEDGMENTS AND ASSOCIATED FOOTNOTES
Department of Geology, University of Toronto, Toronto, Ontario, Canada
Copyright © 2004 by The Society of Canadian Petroleum Geologists. All Rights Reserved.