Baltoscandian conodont biofacies fluctuations and their link to Middle Ordovician (Darriwilian) global cooling

Palaeontology ◽  
2018 ◽  
Vol 61 (3) ◽  
pp. 391-416 ◽  
Author(s):  
Jan A. Rasmussen ◽  
Svend Stouge
Keyword(s):  
Middle Ordovician ◽  
Conodont Biofacies ◽  
Global Cooling

Darriwilian (Middle Ordovician) conodont biofacies from the Central Precordillera of Argentina

2017 ◽  
Vol 130 ◽  
pp. 15-28 ◽  
Author(s):  
Fernanda Serra ◽  
Nicolás A. Feltes ◽  
Miles A. Henderson ◽  
Guillermo L. Albanesi
Keyword(s):  
Middle Ordovician ◽  
Conodont Biofacies

scholarly journals Ordovician conodont biofacies of the upper La Silla and San Juan formations (middle Tremadocian-lower Dapingian) at Cerro La Silla, Argentine Precordillera

2021 ◽  
Author(s):  
Matías J. MANGO ◽  
undefined Guillermo L. ALBANESI
Keyword(s):  
Cluster Analysis ◽  
Sea Level ◽  
Carbonate Rocks ◽  
Carbonate Ramp ◽  
San Juan ◽  
Total Abundance ◽  
Sea Level Changes ◽  
Middle Ordovician ◽  
Conodont Biofacies ◽  
Argentine Precordillera

Conodonts from the upper La Silla (9.6 m thick) and San Juan formations (264.7 m thick) at the Cerro La Silla section are analyzed for the identification of faunal dynamics, biofacies and sea-level changes. The conodont collection of 11 388 specimens was recovered after digestion of 41 samples of carbonate rocks, totalizing 88.155 kg. Conodont total abundance and generic diversity graphs, as well as cluster analysis, reveal seven biofacies. The Colaptoconus, Tropodus-Reutterodus, Oepikodus-Prioniodus, Juanognathus-Bergstroemognathus, Juanognathus-Oepikodus-Protopanderodus, Juanognathus-Protopanderodus, Juanognathus-Semiacontiodus biofacies are determined. These biofacies represent middle to outer carbonate ramp environments for the San Juan Formation. The associated analysis of biofacies and lithology allow for the recognition of two transgressive events in the San Juan Formation at the Cerro La Silla section, which could be related to transgressive systems tracts (TST) that occurred during the Early and Middle Ordovician (middle Tremadocian-early Dapingian).

Holmograptus spinosus and the Middle Ordovician (Darriwilian) graptolite biostratigraphy at Les Méchins (Quebec, Canada)

2009 ◽  
Vol 46 (10) ◽  
pp. 739-755 ◽  
Author(s):  
Jörg Maletz
Keyword(s):  
North America ◽  
Eastern North America ◽  
Middle Ordovician ◽  
Rare Combination ◽  
Conodont Biofacies ◽  
Sponge Spicules ◽  
First Time

The Les Méchins region in Quebec provides a unique opportunity to understand the Darriwilian graptolite succession in eastern North America. The graptolite faunas of the upper member of the Anse au Crapaud Formation include the Arienigraptus gracilis , Oncograptus upsilon , Undulograptus austrodentatus , and Holmograptus spinosus biozone faunas and, thus, complement the well known Darriwilian faunas of the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland. In particular, the Holmograptus spinosus Biozone interval of calcarenitic limestones bears a rare combination of benthic (shelly) and planktic (graptolitic) faunas with conodonts, brachiopods, ostracods, sponge spicules, and algal remains associated with common graptolites that allow an inter-continental correlation. The Holmograptus spinosus Biozone is introduced for the interval based on a diverse and characteristic graptolite fauna. The fauna includes among others, Atopograptus woodwardi , recognized for the first time in North America. The Holmograptus spinosus Biozone fauna can be found worldwide and is easily correlated into the conodont biofacies using species of the genus Histiodella . Ties between graptolite and conodont biozonations are discussed for the Darriwilian. Silicified ostracods are illustrated for the first time from the interval. Hustedograptus quebecensis is described as new.

The earliest ostracods from the Ordovician of the Prague Basin, Czech Republic

2014 ◽  
Vol 64 (4) ◽  
pp. 367-392 ◽  
Author(s):  
Karolína Lajblová ◽  
Petr Kraft
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Massif Central ◽  
Central European ◽  
Middle Ordovician ◽  
Prague Basin ◽  
Barrandian Area ◽  
Fossil Assemblages ◽  
European Variscides

Abstract The earliest ostracods from the Bohemian Massif (Central European Variscides) have been recorded from the Middle Ordovician of the Prague Basin (Barrandian area), in the upper Klabava Formation, and became an abundant component of fossil assemblages in the overlying Šarka Formation. Both early ostracod associations consist of eight species in total, representing mainly eridostracans, palaeocopids, and binodicopids. The revision, description, or redescription of all species and their distribution in the basin is provided. Their diversification patterns and palaeogeographical relationships to ostracod assemblages from other regions are discussed.

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