North American Middle and Upper Ordovician Conodont Faunas

Sweet, Walter C.; Ethington, Raymond L.; Barnes, Christopher R.

doi:10.1130/mem127-p163

Cited by 62 publications

(35 citation statements)

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“…At present, conodonts provide greater biostratigraphic resolution than any other fossil group for the Ordovician platform carbonate rocks (Bergström, 1971;Sweet et al, 1971;Sweet and Bergström, 1976;Sweet, 1984), whereas graptolites are the most useful in the basinal facies that characterize the pericratonic regions of eastern North America (Finney, 1982;. Zonal ties with Lower and early Middle Ordovician trilobites and brachiopods also have been proposed by ; however, benthic shelly faunas Ordovician K-bentonites, eastern North America 13 in the eastern Midcontinent United States tend to be ecologically restricted.…”

Section: Biostratigraphic Frameworkmentioning

confidence: 99%

Ordovician K-bentonites of eastern North America

Kolata¹,

Huff²,

Bergström³

1996

Ordovician K-Bentonites of Eastern North America

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Section: Biostratigraphic Frameworkmentioning

confidence: 99%

Ordovician K-bentonites of eastern North America

Kolata¹,

Huff²,

Bergström³

1996

Ordovician K-Bentonites of Eastern North America

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“…9) by Albanesi & Ortega (2002). The range of the taxon in North America correlates to upper fauna 7 through lower fauna 9 in the older literature (Sweet, Ethington & Barnes, 1971), which is equivalent to the uppermost Baltoniodus gerdae subzone of the Amorphognathus tvaerensis zone through the uppermost Baltoniodus alobatus subzone of the A. tvaerensis zone (Sweet, 1984(Sweet, , 1988 and in terms of North American stages it includes approximately the upper part of the Turinian and the lower part of the Chatfieldian (Fig. 9).…”

Section: S O Egenhoff and Othersmentioning

confidence: 93%

Biostratigraphic precision of the Cruziana rugosa group: a study from the Ordovician succession of southern and central Bolivia

Egenhoff

Weber

Lehnert³

et al. 2007

Geol. Mag.

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-Cruziana ichnospecies have been repeatedly reported to have biostratigraphic significance. This study presents a re-evaluation of the arthropod ichnotaxa of the Cruziana rugosa Group from bio-and/or lithostratigraphically well-defined Lower to Upper Ordovician siliciclastic sections of southern and central Bolivia. With the exception of Cruziana rouaulti, the ichnofaunas contain all the members of the Cruziana rugosa Group throughout the Ordovician (Arenig to Caradoc) successions in Bolivia. The Bolivian material therefore indicates that these arthropod ichnofossil assemblages are suitable for recognizing Ordovician strata in Bolivia. These findings cast doubt on their use as reliable indicators for a global intra-Ordovician (Arenig to Caradoc) biozonation of Peri-Gondwanan sedimentary successions.

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“…10). In North America, A. politus is first found in fauna 9 (Late Mohawkian) and disappears at the end of fauna 12 time (Cincinnatian; Sweet et al 1971;Sweet 1984). Consequently, the presence of the North American conodont A. politus in the Rio Sassito succession indicates that unit 7 is no older than the Late Mohawkian of the North American subdivision or not older than the Middle Caradocian following the European time scale.…”

Section: San Juan Formationmentioning

confidence: 99%

The Rio Sassito sedimentary succession (Ordovician): a pinpoint in the geodynamic evolution of the Argentine Precordillera

Keller¹,

Lehnert²

1998

Geologische Rundschau

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In the Precordillera of western Argentina, an isolated outcrop of Llandeilian siliciclastics and Caradocian limestones (Rio Sassito succession) reveals a complex interplay between the tectonic and the sedimentary history of the Precordillera during Middle and Late Ordovician times. The succession is composed of a lower siliciclastic interval and an upper carbonate interval and is bounded below and above by erosional unconformities. Dating of these unconformities, which in many places merged to form one single surface, demonstrates that the most important erosional event took place prior to the deposition of the Rio Sassito succession. This erosional event is correlated to extensional tectonics during continental breakup and the separation of the Precordillera from Laurentia. Block faulting with the formation of horst and graben structures provided the topography for the establishment of a pelagic carbonate platform during the Caradoc. In our view, there are no indications that these phenomena are related to the accretion of the Precordillera to Gondwana or to the formation of an Ordovician supercontinent. The carbonate sediments are typical of temperate-water settings, characterized by the absence of ooids, oncoids, and algae, and by the presence of abundant abraded bioclasts, intraclasts, and peloids. The inference of a temperate-water environment does not, as previously supposed, indicate the accretion of the Precordillera to Gondwana, but is more likely related to global cooling prior to the Ashgillian glaciation.

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North American Middle and Upper Ordovician Conodont Faunas

Cited by 62 publications

References 0 publications

Ordovician K-bentonites of eastern North America

Ordovician K-bentonites of eastern North America

Biostratigraphic precision of the Cruziana rugosa group: a study from the Ordovician succession of southern and central Bolivia

The Rio Sassito sedimentary succession (Ordovician): a pinpoint in the geodynamic evolution of the Argentine Precordillera

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