| Titre | The Smithian/Spathian boundary (late Early Triassic): a review of ammonoid, conodont, and carbon-isotopic criteria |
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| Auteur | Zhang, L; Orchard, M J ; Brayard, A; Algeo, T J; Zhao, L S; Chen, Z Q; Lyu, Z Y |
| Source | Earth-Science Reviews vol. 195, 2019 p. 7-36, https://doi.org/10.1016/j.earscirev.2019.02.014  Accès ouvert |
| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200184 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.earscirev.2019.02.014 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Région extracotière |
| Lat/Long OENS | -180.0000 180.0000 90.0000 -90.0000 |
| Sujets | Trias inférieur; Smithien; Spathian; isotopes de carbone; analyses thermiques; biostratigraphie; conodontes; Zone de Boreale ; géochronologie; Nature et environnement; Sciences et technologie;
stratigraphie; Trias |
| Illustrations | cartes géochronologiques; échelles stratigraphiques; diagrammes stratigraphiques; cartes de localisation; coupes stratigraphiques; photographies |
| Diffusé | 2019 02 15 |
| Résumé | (disponible en anglais seulement)
The transition from the Smithian substage to the Spathian substage of the Olenekian stage of the late Early Triassic was a critical time marked by a series of
biological and environmental changes during the multimillion-year recovery interval following the end-Permian mass extinction. However, the Smithian/Spathian boundary (SSB) does not yet have an agreed definition, a shortcoming that complicates
high-resolution analysis of events during the Smithian-Spathian transition. Here, we review key biostratigraphic (i.e., ammonoid and conodont) studies of the Smithian and Spathian substages in historically important regions (e.g., the Canadian Arctic
for the Boreal realm, western North America for the eastern Panthalassic Ocean) and more recently re-studied locations (e.g., Pakistan and India in the southern Tethys, South China in the eastern Tethys) as well as the carbon isotope
chemostratigraphy of 29 major Smithian-Spathian sections globally. Key ammonoid genera (e.g., Wasatchites, Anasibirites, Glyptophiceras and Xenoceltites of the late Smithian, and Bajarunia, Tirolites and Columbites of the early Spathian), conodont
species (e.g., Scythogondolella milleri, Novispathodus waageni, and Borinella buurensis of the late Smithian, and Triassospathodus' hungaricus, Neogondolella aff. sweeti, and Icriospathodus spp. of the early Spathian), and carbonate carbon isotope
excursions provide appropriate markers for constraining the SSB. Use of the first occurrence of the conodont Novispathodus pingdingshanensis as a potential marker of the SSB is also discussed. Based on correlations of biostratigraphic and carbon
isotope data globally, we propose to revise previous placements of the SSB transition in some sections. Finally, we show that the Smithian Thermal Maximum (STM; herein named) was middle Smithian in age and not correlative with the SSB, as inferred in
some earlier studies, and that the SSB coincided with a subsequent major global cooling event. |
| GEOSCAN ID | 326596 |
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