Spathian (Lower Triassic) ammonoids from western USA (Idaho, California, Utah and Nevada)

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Ressource 1Télécharger: 49 - Guex 2010.pdf (11549.17 [Ko])
Etat: Public
Version: Final published version
Licence: CC BY-NC-ND 4.0
ID Serval
serval:BIB_5E6D98A0E04B
Type
Livre: un livre et son éditeur.
Collection
Publications
Institution
Titre
Spathian (Lower Triassic) ammonoids from western USA (Idaho, California, Utah and Nevada)
Auteur⸱e⸱s
Guex Jean, Hungerbuehler Alexandre, Jenks James F., O'Dogherty Luis, Atudorei Viorel, Taylor David G., Bucher Hugo, Bartolini Annachiara
Editeur
Université de Lausanne, Institut de Géologie et Paléontologie
Lieu d'édition
Lausanne
ISSN
1015-3578
Statut éditorial
Publié
Date de publication
2010
Peer-reviewed
Oui
Volume
49
Série
Mémoires de Géologie (Lausanne)
Langue
anglais
Nombre de pages
82
Résumé
The Early Triassic marine deposits are distributed over a large area in the Western United State and are very rich in ammonoids. The detailed bed by bed study of their stratigraphic distribution allowed us to present a new very precise biochronological framework of the Spathian stage (Middle to Late Olenekian).
Nineteen new ammonoid species belonging to the genera Pseudosvalbardiceras ?, Prohungarites, Silberlingeria, Bajarunia, Hemilecanites, Arctomeekoceras, Xenoceltites, Nordophiceratoides, Sibirites, Columbites, Hellenites and Svalbardiceras and eighteen new spathian ammonoid genera (Courtilloticeras, Yvesgalleticeras, Marcouxia, Jeanbesseiceras, Tapponnierites, Gaudemerites, Deweveria, Ceccaisculitoides, Coscaites, Eschericeratites, Carteria, Goricanites, Tardicolumbites, Cowboyiceras, Nordophiceratoides, Glabercolumbites) have been described in a recent preliminary report by Guex et al. (2005) on the basis of unpublished material collected in the western USA (Idaho, Utah, Nevada and California).
In addition, one new genus (Rudolftruempyiceras) and four new species are also described in the present work. The precise stratigraphic description of the collected sections is given in the present Memoir and the stratigraphic distribution of 88 species belonging to 51 genera is established herein. Twenty-three new biochronological horizons are defined thanks to these new data. The Cowboy Pass section (Utah) records a very interesting terrestrial (red beds and very shallow water deposits) transition between the marine Late Smithian and the Earliest Spathian faunas. That worldwide short lived regression followed by a major transgression fits the model proposed by Guex et al. 2001 and Morard et al. 2003 for the Pliensbachian - Toarcian transition: major volcanic SO2 emissions generating a short but major cooling and glaciation associated with an important sea level fall and large scale emersions, followed by a warming inducing a transgressive episode with some anoxic deposits.
Open Access
Oui
Création de la notice
30/10/2012 21:44
Dernière modification de la notice
29/08/2023 7:11
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