scholarly journals Ocean euxinia and climate change “double whammy” drove the Late Ordovician mass extinction

Geology ◽  
2018 ◽  
Vol 46 (6) ◽  
pp. 535-538 ◽  
Author(s):  
Caineng Zou ◽  
Zhen Qiu ◽  
Simon W. Poulton ◽  
Dazhong Dong ◽  
Hongyan Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Extinction ◽  
Late Ordovician

scholarly journals Climate change and the selective signature of the Late Ordovician mass extinction

2012 ◽  
Vol 109 (18) ◽  
pp. 6829-6834 ◽  
Author(s):  
S. Finnegan ◽  
N. A. Heim ◽  
S. E. Peters ◽  
W. W. Fischer
Keyword(s):  
Climate Change ◽  
Mass Extinction ◽  
Late Ordovician

scholarly journals Graptolite community responses to global climate change and the Late Ordovician mass extinction

2016 ◽  
Vol 113 (30) ◽  
pp. 8380-8385 ◽  
Author(s):  
H. David Sheets ◽  
Charles E. Mitchell ◽  
Michael J. Melchin ◽  
Jason Loxton ◽  
Petr Štorch ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Mass Extinction ◽  
Climate Changes ◽  
Global Climate ◽  
Extinction Risk ◽  
Late Ordovician ◽  
Ecological Communities ◽  
Mass Extinctions ◽  
The Impact

Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (∼447–444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction.

Hirnantia Fauna from the Condroz Inlier, Belgium: another case of a relict Ordovician shelly fauna in the Silurian?

2021 ◽  
pp. 1-27
Author(s):  
Sofia Pereira ◽  
Jorge Colmenar ◽  
Jan Mortier ◽  
Jan Vanmeirhaeghe ◽  
Jacques Verniers ◽  
...  
Keyword(s):  
Sea Level ◽  
Mass Extinction ◽  
Late Ordovician ◽  
Lake District ◽  
Low Diversity ◽  
Hirnantia Fauna ◽  
And Sea Level

Abstract The end-Ordovician mass extinction, linked to a major glaciation, led to deep changes in Hirnantian–Rhuddanian biotas. The Hirnantia Fauna, the first of two Hirnantian survival brachiopod-dominated communities, characterizes the lower–mid Hirnantian deposits globally, and its distribution is essential to understand how the extinction took place. In this paper, we describe, illustrate, and discuss the first macrofossiliferous Hirnantia Fauna assemblage from Belgium, occurring in the Tihange Member of the Fosses Formation at Tihange (Huy), within the Central Condroz Inlier. Six fossiliferous beds have yielded a low-diversity, brachiopod-dominated association. In addition to the brachiopods (Eostropheodonta hirnantensis, Plectothyrella crassicosta, Hirnantia sp., and Trucizetina? sp.), one trilobite (Mucronaspis sp.), four pelmatozoans (Xenocrinus sp., Cyclocharax [col.] paucicrenulatus, Conspectocrinus [col.] celticus, and Pentagonocyclicus [col.] sp.), three graptolites (Cystograptus ancestralis, Normalograptus normalis, and ?Metabolograptus sp.), together with indeterminate machaeridians and bryozoans were identified. The graptolite assemblage, from the Akidograptus ascensus-Parakidograptus acuminatus Biozone, indicates an early Rhuddanian (Silurian) age, and thus, an unexpectedly late occurrence of a typical Hirnantia Fauna. This Belgian association may represent an additional example of relict Hirnantia Fauna in the Silurian, sharing characteristics with the only other known from Rhuddanian rocks at Yewdale Beck (Lake District, England), although reworking has not been completely ruled out. The survival of these Hirnantian taxa into the Silurian might be linked to delayed post-glacial effects of rising temperature and sea-level, which may have favored the establishment of refugia in these two particular regions that were paleogeographically close during the Late Ordovician–early Silurian.

Llandovery (early Silurian) crinoids from Hiiumaa Island, western Estonia

2016 ◽  
Vol 90 (6) ◽  
pp. 1138-1147 ◽  
Author(s):  
William I. Ausich ◽  
Mark A. Wilson
Keyword(s):  
Mass Extinction ◽  
Late Ordovician

AbstractRhuddanian crinoid faunas are poorly known globally, making this new fauna from the Hilliste Formation of western Estonian especially significant. The Hilliste fauna is the oldest Silurian fauna known from the Baltica paleocontinent, thus this is the first example of the crinoid recovery fauna after the Late Ordovician mass extinction. Hiiumaacrinus vinni n. gen. n. sp., Protaxocrinus estoniensis n. sp., Eomyelodactylus sp., calceocrinids, and five holdfast types are reported here. Although the fauna has relatively few taxa, it is among the most diverse Rhuddanian faunas known. Similar to other Rhuddanian crinoid faunas elsewhere, the Hilliste crinoid fauna contains crinoids belonging the Dimerocrinitidae, Taxocrinidae, Calceocrinidae, and Myelodactylidae; most elements of the new fauna are quite small, perhaps indicative of the Lilliput Effect.

Late Ordovician mass extinction

2007 ◽  
pp. 5-7 ◽  
Author(s):  
Ashraf M. T. Elewa
Keyword(s):  
Mass Extinction ◽  
Late Ordovician

A rock volume accumulation curve for the late Ordovician-Silurian Welsh Basin

1994 ◽  
Vol 131 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Chris J. Clayton
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Late Ordovician ◽  
Tectonic Uplift ◽  
Sudden Increase ◽  
Submarine Fan ◽  
Accumulation Curve ◽  
River Capture ◽  
Iapetus Ocean ◽  
Rate Of Sedimentation

AbstractA rock accumulation curve is presented for the Ordovician-Silurian Welsh Basin, based on the volume of sediment entering the basin during each graptolite biozone. Even allowing for its inherent uncertainties, the curve still illustrates a significant and sudden increase in the rate of sedimentation in early Silurian time. This may be explained by submarine fan migration, large scale climate change, or river capture in the hinterland, but is most likely caused by tectonic uplift at source. This would support models for either an early Silurian, or late Ordovician closure of the Iapetus Ocean

Concepts and analysis of mass extinction with the late Ordovician event as an example

1991 ◽  
Vol 5 (2-4) ◽  
pp. 107-121 ◽  
Author(s):  
Chen Xu ◽  
Rong Jia‐Yu
Keyword(s):  
Mass Extinction ◽  
Late Ordovician

Global carbon isotopic events associated with mass extinction and glaciation in the late Ordovician

1997 ◽  
Vol 132 (1-4) ◽  
pp. 195-210 ◽  
Author(s):  
James D Marshall ◽  
Patrick J Brenchley ◽  
Paul Mason ◽  
George A Wolff ◽  
Ricardo A Astini ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Late Ordovician ◽  
Carbon Isotopic ◽  
Global Carbon
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