scholarly journals Evidence of wildfires and elevated atmospheric oxygen at the Frasnian–Famennian boundary in New York (USA): Implications for the Late Devonian mass extinction

2020 ◽  
Vol 132 (9-10) ◽  
pp. 2043-2054 ◽  
Author(s):  
Zeyang Liu ◽  
David Selby ◽  
Paul C. Hackley ◽  
D. Jeffrey Over
Keyword(s):  
New York ◽  
Mass Extinction ◽  
Atmospheric Oxygen ◽  
Terrestrial Ecosystems ◽  
Atmospheric Composition ◽  
Late Devonian ◽  
Driving Mechanism ◽  
Volcanic Event ◽  
Extinction Events ◽  
Climate Cooling

Abstract The Devonian Period experienced significant fluctuations of atmospheric oxygen (O2) levels (∼25–13%), for which the extent and timing are debated. Also characteristic of the Devonian Period, at the Frasnian–Famennian (F–F) boundary, is one of the “big five” mass extinction events of the Phanerozoic. Fossilized charcoal (inertinite) provides a record of wildfire events, which in turn can provide insight into the evolution of terrestrial ecosystems and the atmospheric composition. Here, we report organic petrology, programmed pyrolysis analysis, major and trace element analyses, and initial osmium isotope (Osi) stratigraphy from five sections of Upper Devonian (F–F interval) from western New York, USA. These data are discussed to infer evidence of a wildfire event at the F–F boundary. Based on the evidence for a wildfire at the F–F boundary we also provide an estimate of atmospheric O2 levels of ∼23–25% at this interval, which is in agreement with the models that predict elevated pO2 levels during the Late Devonian. This, coupled with our Os isotope records, support the currently published Osi data that lacks any evidence for an extra-terrestrial impact or volcanic event at the F–F interval, and therefore to act as a trigger for the F–F mass extinction. The elevated O2 level at the F–F interval inferred from this study supports the hypothesis that pCO2 drawdown and associated climate cooling may have acted as a driving mechanism of the F–F mass extinction.

Enhanced paleo-wildfire occurrences caused by marine organic carbon burial during the Late Devonian Frasnian–Famennian mass extinction

2021 ◽  
Author(s):  
Man Lu ◽  
YueHan Lu ◽  
Takehitio Ikejiri ◽  
Richard Carroll
Keyword(s):  
Organic Carbon ◽  
Mass Extinction ◽  
Atmospheric Oxygen ◽  
Burial Rate ◽  
Carbon Burial ◽  
Chattanooga Shale ◽  
Chemical Index ◽  
Organic Carbon Burial ◽  
Polycyclic Aromatic ◽  
Extinction Events

<p>The Frasnian–Famennian (F–F) boundary is characterized by worldwide depositions of organic-rich strata, a series of marine anoxia events and one of the biggest five mass extinction events of the Phanerozoic. Due to the enhanced burial of organic matter, a coeval positive carbon isotope (δ<sup>13</sup>C) excursion occurred around the F–F boundary, raising questions about carbon cycle feedbacks during the mass extinction. In this study, we test the hypothesis that enhanced burial organic carbon during the F–F mass extinction led to the rise of paleo-wildfire occurrences. Here, we reconstructed paleo-wildfire changes across the F–F boundary via analyzing fossil charcoal (inertinites) and pyrogenic polycyclic aromatic hydrocarbons (PAHs) from an Upper Devonian Chattanooga Shale in the southern Appalachian Basin. Our data show low abundances of inertinites and pyrogenic PAHs before the F–F transition and an increasing trend during the F–F transition, followed by a sustained enhancement through the entire Famennian interval. The changes in paleo-wildfire proxies suggest a rise of wildfires starting from the F–F transition. Furthermore, we quantified the amount of organic carbon burial required to drive the observed δ<sup>13</sup>C excursion using a forward box model. The modeling results show an increased carbon burial rate after the onset of the F–F transition and peaking during its termination. The comparison of the carbon burial rate and wildfire proxies indicates that widespread organic carbon burial during the F–F transition might cause elevated atmospheric oxygen levels and hence increased occurrences of wildfires. In addition, chemical index alteration index and plant biomarkers suggest a drying climate initiated during the F–F transition, implying that the enhanced carbon burial probably result in the climate change and amplify the wildfire occurrences.</p>

4. The great catastrophes

2019 ◽  
pp. 51-75
Author(s):  
Paul B. Wignall
Keyword(s):  
Big Five ◽  
Mass Extinction ◽  
Early Jurassic ◽  
Late Devonian ◽  
Mass Extinctions ◽  
Short Intervals ◽  
Extinction Rates ◽  
The World ◽  
Extinction Events ◽  
Mass Extinction Events

What is a mass extinction? Mass extinction events are geologically short intervals of time (always under a million years), marked by dramatic increases of extinction rates in a broad range of environments around the world. In essence they are global catastrophes that left no environment unaffected and that have fundamentally changed the trajectory of life. ‘The great catastrophes’ describes the big five mass extinctions—the end-Ordovician 445 million years ago, the Late Devonian 374 million years ago, the Permo-Triassic 252 million years ago, the end-Triassic 201 million years ago, and Cretaceous-Paleogene sixty-six million years ago—and thoughts on their likely causes, along with other important extinction events identified at the start of the Cambrian and in the Early Jurassic.

Death Star or Coherent Catastrophism?

Impact! ◽  
1996 ◽  
Author(s):  
Gerrit L. Verschuur
Keyword(s):  
New York ◽  
Mass Extinction ◽  
Mass Extinctions ◽  
Life Threatening ◽  
Great Discovery ◽  
Regular Manner ◽  
Goddard Institute ◽  
Extinction Events ◽  
The University ◽  
Mass Extinction Events

Our instinct for survival drives us to learn as much as possible about what goes on around us. The better we understand nature, the better we will be able to predict its vagaries so as to avoid life-threatening situations. Unfortunately, nature is seldom so kind as to arrange for disasters to occur like clockwork, yet that does not dampen our enthusiasm when even a hint of periodicity in a complex phenomenon is spotted. This helps account for the furor that was created when a few paleontologists claimed that mass extinctions of species seemed to recur in a regular manner. A cycle, a periodicity, had been found! That implied that perhaps they might be able to predict nature’s next move. This is how I interpret the extraordinary public interest that was generated by the claims made around 1984 that the mass extinction phenomenon showed a roughly 30-million-year period (others said it was 26 million years). Almost immediately, several books appeared on the subject as well as many, many articles in the popular press and in science magazines. This activity marked the short life of the Death Star fiasco. Given our instinctual urge to look for order in the chaos of existence, the identification of a periodicity in mass-extinction events was a great discovery, if real. What was not highlighted by those who climbed aboard the bandwagon, however, was that the last peak in the pattern occurred about 13 million years ago. If impact-related mass extinction events were produced every 30 million years, there obviously was no cause for concern that we would be hit by a 10-kilometer object in the next 17 million years. Phew! I think that the suggestion that mass extinctions occurred on a regular cycle caused as much interest as it did because we all want to believe that there is no immediate danger to us. The Death Star fiasco began when David Raup and John Sepkowski of the University of Chicago published a report claiming that mass extinction events recurred about every 26 million years. They were followed by Michael Rampino and Richard Stothers of the Goddard Institute for Space Studies in New York who claimed that the period was more like 30 million years, at least during the last 250 million years.

Devonian bryozoan diversity, extinctions, and originations

1996 ◽  
Vol 70 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Alan S. Horowitz ◽  
Joseph F. Pachut ◽  
Robert L. Anstey
Keyword(s):  
New York ◽  
Mass Extinction ◽  
Major Change ◽  
Local Effect ◽  
The Other ◽  
Radiometric Dating ◽  
Late Devonian ◽  
Accurate Data ◽  
Raw Data ◽  
Global Event

Observed diversity of bryozoans within Devonian stages is not significantly different from range-through values for species because very few species have ranges longer than a single stage. Generic diversity differs significantly between observed stadial and stadial range-through values except for the diverse Givetian faunas. Among families, observed stadial and range-through comparisons differ significantly in the lower diversity Early and Late Devonian but are not significant in the taxonomically diverse Middle Devonian. The patterns of Devonian generic and familial diversity are apparently robust proxies for specific diversity.Givetian specific and generic extinctions, based on generated bootstrap distributions, are significantly higher than the other six Devonian stages even when modifications for different stage durations are considered. Based on present data, we conclude that a major change in Devonian diversity occurred between the Givetian and the Frasnian stages. Givetian specific and generic extinctions are not “smeared” with respect to adjacent stages and should qualify as a mass extinction among bryozoans pending more accurate data on bryozoan ranges and more precision in radiometric dating of Devonian stadial boundaries. Devonian bryozoan familial extinctions are not numerous and do not exhibit a significant number of extinctions for any stage. The Givetian extinction, which for the time being ranks as the largest bryozoan extinction in the Phanerozoic, is a global event with a marked local effect in the Hamilton-Tully fauna of New York, Pennsylvania, and Ontario.Givetian specific originations are significantly higher than bootstrap distributions for both raw data and data modified for stadial durations. A Givetian generic high in originations for raw data is not significant when modified for stadial durations and only Eifelian familial originations are significantly higher than bootstrapped distributions.

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