Lower Toarcian (Upper Liassic) Black Shales of the Central European Epicontinental Basin: A Sequence Stratigraphic Case Study from the Sw German Posidonia Shale

Röhl, Hans–Joachim; Schmid‐Röhl, Annette

doi:10.2110/pec.05.82.0165

Cited by 63 publications

(87 citation statements)

References 60 publications

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“…The episodic return of oxygenated conditions is suggested by sparse bivalves in the black shale (Galácz, 1991). However, based on the estimates of Röhl and Schmid-Röhl (2005) from the Posidonia Shale, these episodes may have lasted only few months or years.…”

Section: Intervalmentioning

confidence: 99%

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

Baranyi

Pálfy

Görög

et al. 2016

Review of Palaeobotany and Palynology

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Major palaeoenvironmental and palaeoceanographical changes occurred during the Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE), due to a perturbation of the global carbon cycle and a crisis in marine ecosystems. The sequence of environmental change and regional differences during the T-OAE are not yet fully understood and organic-walled phytoplankton and other palynomorphs are well-suited, but under-utilised, in research into this event. Based on quantitative palynological analyses from a black shale-bearing succession at Réka Valley in the Mecsek Mountains of southwest Hungary, five sequential palynomorph assemblages are distinguished. These reveal major shifts in organic-walled phytoplankton communities, driven by palaeoenvironmental changes. In addition, palynofacies analysis helped to document changes in the composition of sedimentary organic matter, and to quantify the terrestrial input. Assemblage 1 is characterised by a moderately diverse phytoplankton community and high levels of terrestrial palynomorphs. Assemblage 2 records a significant peak of the euryhaline dinoflagellate cyst Nannoceratopsis. Assemblage 3 is distinguished by dominance of highly opportunistic prasinophytes and the temporary disappearance of all dinoflagellate cyst taxa. Assemblages 4 and 5 represent distinctive phases of a prolonged recovery phase with low diversity phytoplankton assemblages and intermittently high levels of terrestrially-derived palynomorphs. The successive disappearance of phytoplankton taxa and the gradual takeover by opportunistic euryhaline species at the onset of the T-OAE were related to several phenomena. These include reduced salinity in the surface waters, establishment of a stable pycnocline and deterioration of nutrient recycling, followed by oxygen deficiency throughout much of the water column. The high amount of terrestrially-derived palynodebris indicates intense runoff and freshwater input, driven by the early Toarcian warming and the enhanced hydrological cycle. Comparison with coeval European successions proves that the palaeoenvironmental changes during the T-OAE were not entirely synchronous, and local factors played a crucial role in influencing phytoplankton communities. In the Mecsek Basin, regional freshening of the surface waters and increased terrestrial input due to the proximity of the hinterland had a greater influence on phytoplankton communities compared to the open oceanic setting of the Tethys to the south.

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Section: Intervalmentioning

confidence: 99%

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

Baranyi

Pálfy

Görög

et al. 2016

Review of Palaeobotany and Palynology

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“…By contrast, because of the rare outcrops, there are only patchy data from the Bernese Jura and Mont Terri area. Based on new and hitherto unpublished sections, and new and revised biostratigraphic data (ammonites, ostracodes), the chrono-and lithostratigraphic Dean et al (1961), sensu Bloos (1979) and sensu Schlegelmilch (1992); I = Psilonotenbank (e.g., LGRB 2004; Bloos et al 2005;Etzold et al 2010); II = Oolithenbank (e.g., Schloz 1972;Bloos et al 2005;Schmid et al 2008); III = Kupferfelsbank (e.g., LGRB 2004; Schmid et al 2008); IV = Davoei-Bank (e.g., Schlatter 1991;LGRB 2004); V = Unterer Stein (e.g., Urlichs 1977;Röhl and Schmid-Röhl 2005); * = likely b The Staffelegg Formation Dean et al (1961), sensu Bloos (1979), sensu Brenner (1986) and sensu Schlegelmilch (1992); see also Beutler et al (2005), von Hillebrandt and Krystyn (2009), Etzold et al (2010). 1 Klettgau area; 2 Lindau well; 3 Weiach well; 4 eastern Tabular Jura; 5 eastern Aargau Tabular Jura ( Fig.…”

Section: Methodsmentioning

confidence: 99%

The Staffelegg Formation: a new stratigraphic scheme for the Early Jurassic of northern Switzerland

Reisdorf

Wetzel

Schlatter³

et al. 2011

Swiss J Geosci

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“…Smith and Wuttke (2012), however, are critical concerning this way of embedding, and-as will be indicated below-their critical evaluation is justified. Seilacher (1982) had already noticed that organic-rich, muddy sediments such as the Posidonienschiefer tend to accumulate under tranquil conditions, but Reisdorf et al (2012) argue-like several others (Kaufmann 1981;Röhl and Schmid-Röhl 2005;Schieber et al 2007)-that some evidence of weak to moderate currents indicates changes in the depositional environment. These currents might have eroded some of the smaller bones, although-as Reisdorf et al (2012) agree-the cohesive bottom sediments would have required a relatively strong current, depending on the degree of the sediment's consolidation.…”

Section: The Posidonienschiefer Conditionsmentioning

confidence: 96%

Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion

Loon

2013

Palaeobio Palaeoenv

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Some well-preserved ichthyosaurs found in the Early Jurassic Posidonienschiefer Formation at Holzmaden (Germany) have puzzled palaeontologists for a long time: their skeletons are exceptionally well preserved and their bones are almost all in situ, but the bones of their embryos are scattered, partly beyond the body limits of the mother. This has been explained initially by bottom currents and later by a displacement of already disarticulated embryos during the expulsion of putrefaction gases through the disrupted body wall of the mother. It was postulated recently that this latter hypothesis is not tenable. It is argued here that both hypotheses are not tenable in their original form, but that carcass implosion may explain the various enigmatic features.

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Lower Toarcian (Upper Liassic) Black Shales of the Central European Epicontinental Basin: A Sequence Stratigraphic Case Study from the Sw German Posidonia Shale

Cited by 63 publications

References 60 publications

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

The Staffelegg Formation: a new stratigraphic scheme for the Early Jurassic of northern Switzerland

Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion

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