Titre
Facies, depositional environment, and palaeoecology of the Middle Triassic Cassina Beds (Meride Limestone, Monte San Giorgio, Switzerland).
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
Auteur(s)
Stockar, R.
Auteure/Auteur
Liens vers les personnes
Liens vers les unités
ISSN
1661-8726
Statut éditorial
Publié
Date de publication
2010
Volume
103
Première page
101
Dernière page/numéro d’article
119
Peer-reviewed
Oui
Langue
anglais
Résumé
The Ladinian Cassina beds belong to the fossiliferous levels of the world-famous Middle Triassic Monte San Giorgio Lagerstatte (UNESCO World Heritage List, Canton Ticino, Southern Alps). Although they are a rich archive for the depositional environment of an important thanatocoenosis, previous excavations focused on vertebrates and particularly on marine reptiles. In 2006, the Museo Cantonale di Storia Naturale (Lugano) started a new research project focusing for the first time on microfacies, micropalaeontological, palaeoecological and taphonomic analyses. So far, the upper third of the sequence has been excavated on a surface of around 40 m(2), and these new data complete those derived from new vertebrate finds (mainly fishes belonging to Saurichthys, Archaeosemionotus, Eosemionotus and Peltopleurus), allowing a better characterization of the basin. Background sedimentation on an anoxic to episodically suboxic seafloor resulted in a finely laminated succession of black shales and limestones, bearing a quasi-anaerobic biofacies, which is characterized by a monotypic benthic foraminiferal meiofauna and has been documented for the first time from the whole Monte San Giorgio sequence. Event deposition, testified by turbidites and volcaniclastic layers, is related to sediment input from basin margins and to distant volcanic eruptions, respectively. Fossil nekton points to an environment with only limited connection to the open sea. Terrestrial macroflora remains document the presence of emerged areas covered with vegetation and probably located relatively far away. Proliferation of benthic microbial mats is inferred on the basis of microfabrics, ecological considerations and taphonomic (both biostratinomic and diagenetic) features of the new vertebrate finds, whose excellent preservation is ascribed to sealing by biofilms. The occurrence of allochthonous elements allows an insight into the shallow-waters of the adjoining time-equivalent Salvatore platform. Finally, the available biostratigraphic data are critically reviewed.
PID Serval
serval:BIB_030634F27347
Open Access
Oui
Date de création
2011-07-08T09:32:58.296Z
Date de création dans IRIS
2025-05-20T13:21:19Z
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Nom
REF.pdf
Version du manuscrit
published
Taille
2.78 MB
Format
Adobe PDF
PID Serval
serval:BIB_030634F27347.P001
URN
urn:nbn:ch:serval-BIB_030634F273473
Somme de contrôle
(MD5):7ff4fb3ccfd10e0d3c982c13414f6de4