Microproblematica, calcareous algae, and microbialites at the Frasnian-Famennian boundary interval in the Šumbera section (Moravian Karst, Czech Republic) and their significance in the context of the Kellwasser Crisis

Weiner, Tomáš; Weinerová, Hedvika; Kalvoda, Jiří

doi:10.1007/s10347-018-0538-z

Cited by 2 publications

(1 citation statement)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A substantial faunal turnover and notable decline in abundance of encrusting communities have been observed across the upper Frasnian and lower Famennian in the area studied by Zatoń et al (2017), however, it is uncertain whether the disappearance of such algae on the lower Famennian shelly substrates resulted from palaeoenvironmental changes associated with the Frasnian-Famennian event itself or was it due to taphonomic factors. As Rothpletzella is known from the Famennian deposits of other areas (e.g., Feng et al 2010;Weiner et al 2018), it is reasonable to assume that their very low abundance on the upper Frasnian shells and absence on the lower Famennian shells in the area studied resulted from taphonomic reasons: only those thalli which entered a specific microenvironment had a chance to be pyritized and thus fossilized. Such reducing microenvironment in the sediment is uncommon in most shallow, well-oxygenated waters within the photic zone.…”

Section: Comparisons and Affinities Of The Fossilsmentioning

confidence: 90%

Enigmatic encrusting fossils from the Upper Devonian of Russia: probable Rothpletzella microproblematica preserved in three dimensions

Zatoń

Jarochowska

2018

Historical Biology

View full text Add to dashboard Cite

Intriguing microfossils encrusting certain Upper Devonian brachiopod shells from the Central Devonian Field, Russia, are reported for the first time. The fossils are pyritized, have fan-shaped morphologies and are formed by tightly-packed branches which divide dichotomously at different points in their development. The organisms preserved grew horizontally on shelly substrates. Comparisons with similar fossils known from the literature indicate that they do not represent any animal taxon commonly encrusting hard substrates. Instead, the morphology, organization and growth mode of these fossils are most similar to microfossils known under the name Rothpletzella, which so far have only been known from thin sections. Rothpletzella is a problematicum for which algal affinities have been proposed. The preserved branches of the fossils described here are too large for cyanobacterial cells. Their large size suggests their placement, along with other described Rothpletzella fossils, within the green algae order Bryopsidales. It is suggested that originally, these organisms 2 possessed thalli encased within a thin, delicate calcified sheath. After burial the thalli underwent pyritization via sulphate reduction mediated by bacterial activity within low pH, dysoxic microenvironment, and their sheath dissolved. As three-dimensionally preserved, these algae provide a new, previously unrecognized, component within the Devonian encrusting communities.

show abstract

Section: Comparisons and Affinities Of The Fossilsmentioning

confidence: 90%

Enigmatic encrusting fossils from the Upper Devonian of Russia: probable Rothpletzella microproblematica preserved in three dimensions

Zatoń

Jarochowska

2018

Historical Biology

View full text Add to dashboard Cite

show abstract

Paleogeography and paleoenvironments of the Late Devonian Kellwasser event: A review of its sedimentological and geochemical expression

Carmichael

Waters

Königshof

et al. 2019

Global and Planetary Change

View full text Add to dashboard Cite

The Late Devonian (383-359 Ma) was a time of prolonged climate instability with catastrophic perturbation of global marine ecosystems at the Frasnian-Famennian (F-F) and the Devonian-Carboniferous (D-C) boundaries. The causes and mechanisms of anoxia and extinction at the F-F interval are not clearly delineated, and alternative explanations for virtually every aspect of this interval are still intensely debated. In many (but not all) locations, the F-F interval is characterized by two dark, organic-rich lithologies: the Lower and Upper Kellwasser beds (as originally described in Germany) that represent a stepwise ocean anoxia and extinction sequence. The Upper and Lower Kellwasser anoxia event beds are often collectively termed the Kellwasser Event, and the termination of this sequence is within the Upper Kellwasser Event at the F-F boundary. Current knowledge is limited by significant sampling bias, as most previous studies sampled epicontinental seaways or passive continental shelves, primarily from localities across Europe and North America. Together these formed a single equatorial continent with a rising mountain chain during the Late Devonian. Our understanding of the Kellwasser Event is thus based on data and observations from a restricted set of paleoenvironments that may not represent the complete range of Late Devonian environments and oceanic conditions. In the last decade, new methodologies and research in additional paleoenvironments around the world confirm that the Kellwasser Event was global in scope, but also that its expression varies with both paleoenvironment and paleogeography. Studying the many differing geochemical and lithological expressions of the Kellwasser Event using a) a wide variety of paleoenvironments, b) a multiproxy approach, and c) placement of results into the broader context of Late Devonian marine biodiversity patterns is vital for understanding the true scope of ocean anoxia, and determining the causes of the marine biodiversity crisis at the F-F boundary.

show abstract

Microproblematica, calcareous algae, and microbialites at the Frasnian-Famennian boundary interval in the Šumbera section (Moravian Karst, Czech Republic) and their significance in the context of the Kellwasser Crisis

Cited by 2 publications

References 69 publications

Enigmatic encrusting fossils from the Upper Devonian of Russia: probable Rothpletzella microproblematica preserved in three dimensions

Enigmatic encrusting fossils from the Upper Devonian of Russia: probable Rothpletzella microproblematica preserved in three dimensions

Paleogeography and paleoenvironments of the Late Devonian Kellwasser event: A review of its sedimentological and geochemical expression

Contact Info

Product

Resources

About