Results 141 to 150 of about 2,013 (181)

Central Appalachian Late Ordovician Communities

Geological Society of America Bulletin, 1969
The fossiliferous beds at the top of the Reedsville and Martinsburg Formations (Upper Ordovician) in the central Appalachians, including the classic Orthorhynchula Zone, provide one of the earliest known examples of a prolific nearshore, clastic-facies fauna that contains species of distinctly modern aspect. A study of the faunal associations and their
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Late Ordovician conulariids from Manitoba, Canada

Journal of Paleontology, 2013
Six species of conulariids, assigned to four genera, were recovered from the type locality of the Cat Head Member of the Red River Formation in southern Manitoba, Canada. These are middle Katian (Late Ordovician) in age. The most abundant conulariid species from this locality,Conularia porcella, is new, and is represented by 21 specimens. Additionally,
Sean P. Robson, Graham A. Young
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Late Ordovician glaciation in southern Turkey

Terra Nova, 2003
ABSTRACT We present a new survey of several Palaeozoic sections in both the Taurus range and the Border Folds that documents typical glacial features including a glacial pavement and striated dropstones (Halevikdere Formation) and demonstrates the former presence of an ice sheet in southern and south‐eastern Turkey.
Monod, Olivier, Kozlu, H., Ghienne, J.-F., T. Dean, W., Günay, Y., Le Hérissé, Alain, Paris, Florentin, Robardet, M.   +7 more
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The Late Ordovician Mass Extinction

Annual Review of Earth and Planetary Sciences, 2001
▪ Abstract  Near the end of the Late Ordovician, in the first of five mass extinctions in the Phanerozoic, about 85% of marine species died. The cause was a brief glacial interval that produced two pulses of extinction. The first pulse was at the beginning of the glaciation, when sea-level decline drained epicontinental seaways, produced a harsh ...
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Reconstructing Late Ordovician carbon cycle variations

Geochimica et Cosmochimica Acta, 2013
Abstract The role of carbon dioxide in regulating climate during the early Paleozoic, when severe glaciations occurred during a putative greenhouse world, remains unclear. Here, we present the first molecular carbon isotope proxy-based estimates for Late Ordovician (early Katian) pCO2 levels, and explore the limitations of applying this approach to ...
Pancost, Richard D., Freeman, Katherine H., Herrmann, Achim D., Patzkowsky, Mark E., Ainsaar, Leho, Martma, Tõnu   +5 more
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Late Middle Ordovician environmental change and extinction: Harbinger of the Late Ordovician or continuation of Cambrian patterns?

Geology, 1997
Positive excursions in carbon isotope compositions of carbonate (∼ 3‰) and organic carbon (∼ 4‰–6‰) from the late Middle Ordovician (middle Caradocian) of the midcontinent and the eastern United States indicate widespread increases in productivity and rates of organic carbon burial that may have drawn down atmospheric p CO 2 , precipitating global ...
Patzkowsky, ME, Slupik, LA, Arthur, MA, Pancost, RD, Freeman, KH   +4 more
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Late Ordovician lingulate brachiopods from Estonia

1994
(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
Popov, Leonid, Nolvak, Jaak, Holmer, Lars E   +2 more
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Late Ordovician global warming—The Boda event

Geology, 2005
There is substantial evidence for mid-Ashgillian global warming before the latest Ordovician Hirnantian glaciation, as shown by the movement of previously lower latitude benthic faunas such as trilobites and brachiopods to progressively higher latitudes and by an increase in endemic faunas at low latitudes.
Richard A. Fortey, L. Robin M. Cocks
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Late Ordovician brachiopod communities of southeast China

Canadian Journal of Earth Sciences, 2002
The Upper Ordovician (mid-Ashgill) Xiazhen and Changwu formations in the Zhejiang-Jiangxi border region of southeastern China contain an abundant and diverse suite of brachiopods. A cluster analysis of 59 key samples from 180 collections (over 23 000 specimens) allowed delineation of eight distinct brachiopod communities, herein named the Ectenoglossa ...
Ren-bin Zhan, Jia-yu Rong, Jisuo Jin, L RM Cocks   +3 more
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Late Ordovician trilobites from southern Thailand

1997
(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
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