Quantitative stratigraphy of the Wufeng and Lungmachi black shales and graptolite evolution during and after the Late Ordovician mass extinction

AbstractRecently, the end-Devonian mass extinction (Hangenberg Crisis, 359 Ma) was identified as a first-order mass extinction, albeit not one of the “Big Five” events. Many marine and terrestrial organisms were affected by this crisis. The cause of this mass extinction is still conjectural and widely discussed. Here we report anomalously high mercury (Hg) concentrations from the South Tian Shan (Uzbekistan), together with correlation using conodont biostratigraphic data. Hg enrichment (to 5825 ppb) was detected in marine deposits encompassing the Hangenberg Crisis. In the Novchomok section, the Hangenberg Crisis interval does not contain typical Hangenberg Black Shales; however, by means of inorganic geochemistry (enrichment of redox-sensitive elements such as Mo, V, and U) we detected an equivalent level despite the lack of marked facies changes. This is the first record of Hg and Hg/total organic carbon anomalies in marly shales, marls and carbonates that are totally independent of facies changes, implying that volcanism was the most probable cause of the Hangenberg Crisis. This conclusion is confirmed by the presence of a negative δ13C excursion, which may reflect massive release of isotopically light carbon from volcanogenic and thermogenic devolatilization likely combined with increased arc-volcanism activity worldwide at the end of the Devonian.

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

Journal of Paleontology ◽

10.1017/jpa.2021.74 ◽

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.

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THE CLIMATIC SIGNIFICANCE OF LATE ORDOVICIAN–EARLY SILURIAN BLACK SHALES

10.1130/abs/2019am-336415 ◽

2019 ◽

Author(s):

Alexandre Pohl ◽

◽

Yannick Donnadieu ◽

Guillaume Le Hir ◽

...

Keyword(s):

Late Ordovician ◽

Black Shales

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

Journal of Paleontology ◽

10.1017/jpa.2016.120 ◽

2016 ◽

Vol 90 (6) ◽

pp. 1138-1147 ◽

Cited By ~ 6

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.

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Late Ordovician mass extinction

Mass Extinction ◽

10.1007/978-3-540-75916-4_2 ◽

2007 ◽

pp. 5-7 ◽

Cited By ~ 2

Author(s):

Ashraf M. T. Elewa

Keyword(s):

Mass Extinction ◽

Late Ordovician

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Extinction: Late Ordovician Mass Extinction

Encyclopedia of Life Sciences ◽

10.1038/npg.els.0001652 ◽

2001 ◽

Author(s):

Patrick John Brenchley

Keyword(s):

Mass Extinction ◽

Late Ordovician

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The Kara astrobleme size, age and potential paleo-ecological effects of the impact event (European Arctic Zone, Russia)

10.5194/egusphere-egu21-8523 ◽

2021 ◽

Author(s):

Tatyana Shumilova

Keyword(s):

Mass Extinction ◽

Black Shales ◽

Ecological Effects ◽

Impact Event ◽

Arctic Zone ◽

Russian Science ◽

Future Possibility ◽

Impact Melt ◽

European Arctic ◽

The Impact

The Kara astrobleme is one of the biggest meteoritic craters which is set at the Baydarata Bay of the Kara sea (European Arctic Zone, Russia). It is a result of the catastrophic impact event occurred close to the K/&#1058; extinction. The Kara astrobleme is the largest European crater at the modern erosion level.&#160; At present it is estimated with the diameter from rim to rim about 65 km. While, some scientists have proposed its larger initial size &#8211; up to 120 km diameter, but no any well presented proof has been provided for the hypothesis. In 2015-2019 we have provided wide geological observations at the Kara crater and the near-set Ust`-Kara area (UKA) impactites. We have found for the first time that the UKA impactites, described in earlier Russian scientists publications as a synchronic independent crater of the same bolide, can be presented with bottom-flow impactites from the Kara crater (Shumilova et al., 2020). The found bottom-flow impactites abundant with belt-like impact melt bodies enriched in coesite and liquation structures similar to the Kara UHPHT vein and vein-like melt bodies with UHPHT impact glasses. Thus, they belong to UHPHT impactites. According to our air-bird view observations and impactites outcrops description at the UKA we support the hypothesis of the larger Kara crater getting 100-120 km in diameter of the initially originated size. Such giant meteorite event should be followed by catastrophic effects at the planet level, such as mass extinction. The present accepted Kara impact event age followed by the most recent measurements by 40Ar-39Ar method is equal to 70.3 &#177; 2.2 Ma (Trieloff et al., 1998), that is a bit earlier than the Cretaceous/Tertiary boundary (K/&#1058;) mass extinction at 66 Ma. But, previously, Kara age has been proposed by 65.7 Ma as a probable K/T impact (Kolesnikov et al., 1988; Nazarov et al., 1992). According to different data, the Kara event age lies within the range from 60 to 81 Ma (Masaitis & Mashchak, 1982; Nazarov et al., 1989; Kolesniov et al., 1990; Koeberl et al., 1990). It is clear that the accuracy of the age measurements depend on the quality of the studied samples, including their crystallinity, velocity of impact melt cooling and alteration, and from the used type of a method. By the moment, we have found out &#8220;in situ&#8221; crystallized zircons within the just discovered real UHPHT impact melt glasses (Shumilova et al., 2018, 2020). The UHPHT glasses do not have any alteration, thus, they can be used for accurate age measurements. Taking a future possibility for more accurate age analysis in the nearest future we can propose a correct vision of the possibility of the giant Kara influence to K-T mass extinction or other ecological effects. In any case following to the giant size of the Kara event touched the sedimentary rocks abundant with black shales and carbonates, which should be a result of essential atmospheric changes. The study has been supported by the Russian Science Foundation project #17-17-01080.

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