Geochemistry of the Frasnian-Famennian boundary in Belgium: Mass extinction, anoxic oceans and microtektite layer, but not much iridium?

Claeys, Philippe; Kyte, Frank T.; Herbosch, Alain; Casier, Jean-Georges

doi:10.1130/0-8137-2307-8.491

Cited by 15 publications

(17 citation statements)

References 34 publications

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“…But there are no anomalous concentrations of iridium so far in the sampled sections of Ž . Belgium Claeys et al, 1994;McGhee, 1996 and nothing unequivocal, right The effect of an extraterrestrial body crash on global climate has often been discussed. ALarge amounts of debris from the vaporized bolide and impact site would be injected into the atmosphere.…”

Section: Sinsin Sectionmentioning

confidence: 99%

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Late Frasnian–Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations

Streel

Caputo

Loboziak

et al. 2000

Earth-Science Reviews

270

122

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Palynomorph distribution in Euramerica and western Gondwana, from the Latest Givetian to the Latest Famennian, may be explained, to some extent, by climatic changes. Detailed miospore stratigraphy dates accurately the successive steps of these changes. Interpretation is built on three postulates which are discussed: Euramerica at slightly lower latitudes than generally accepted by most paleomagnetic reconstructions; a conodont time-scale accepted as the most used available subdivision of time; and Late Devonian sea-level fluctuations mainly governed by glacio-eustasy. The Frasnian-Famennian timescale is also evaluated.The comparison, based on conodont correlations, between Givetian and most of the Frasnian miospore assemblages from, respectively, northern and southern Euramerica demonstrates a high taxonomic diversity in the equatorial belt and much Ž . difference between supposed equatorial and sub tropical vegetations. On the contrary, a similar vegetation pattern and therefore probably compatible climatic conditions were present from tropical to subpolar areas. A rather hot climate culminated during the Latest Frasnian when equatorial miospore assemblages reached their maximum width. The miospore diversity shows also a rather clear global Late Frasnian minimum which is also recorded during the Early and Middle Famennian but only in low latitude regions while, in high latitude, very cold climates without perennial snow may explain the scarcity of miospores and so, of vegetation.The Early and Middle Famennian conspicuous latitudinal gradient of the vegetation seems to attenuate towards the Late and Latest Famennian but this might be above all the result of the development, of cosmopolitan coastal lowland vegetations Ž . downstream swamps depending more on the moisture and equable local microclimates than on the probably adverse climates of distant hinterland areas. During that time, periods of cold climate without perennial snow cover and with rare vegetation may have alternated with less cold but wetter climates, thus giving rise to the development of mountain glaciers in high latitudes and explaining the jerking character of the global major marine regression. In high latitude regions, the development of an ice cap reaching sea level is only recorded by the end of the Latest Famennian, immediately below the Ž . DCB but, even if glacial evidences are not known at near the FFB, a short 0.1 Ma? glaciation seems the best reasonable explanation of the major eustatic fall following the Kellwasser Event. The sudden growth and decay of a hypothetical ) Corresponding author. Tel.: q32-4-366-5498; fax: q32-4-366-5338.Ž . E-mail address: maurice.streel@ulg.ac.be M. Streel . Earliest Famennian ice sheet can be explained by the reduction and, later, increase in greenhouse capacity of the atmosphere. These changes in the atmospheric CO might have provoked changes in the mode of ocean-atmosphere operation. It may 2 also be partly controlled by a volcanic paroxysm andror bolide impacts. The Hony microtektites represe...

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Section: Sinsin Sectionmentioning

confidence: 99%

“…19 . Ž Several authors Claeys, 1993;Claeys et al, 1994Claeys et al, , . 1996Herbosch et al, 1996Herbosch et al, , 1997a have subsequently proposed that the upper unit probably represents a deepening of the depositional environment.…”

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confidence: 99%

Late Frasnian–Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations

Streel

Caputo

Loboziak

et al. 2000

Earth-Science Reviews

270

122

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“…8c). The minimum values of Al 2 O 3 , SiO 2 , K 2 O and Zr found at the boundary correspond also to the minimum in (SREE) + Sc + Y, indicating a low terrigenous input (Claeys et al 1996;Pattan et al 2005). Cerium exhibits multiple valences (Ce 3+ , Ce 4+ ).…”

Section: Discussionmentioning

confidence: 75%

Geochemical record of Late Devonian to Early Carboniferous events, Palaeozoic of Graz, Eastern Alps, Austria

Bojar

Neubauer

Koeberl

2013

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The late Famennian mass extinction has been associated with a worldwide anoxic event evidenced at many sites by the accumulation of organic-rich shales starting prior to the DevonianCarboniferous (D/C) boundary. Environmental reconstructions are hampered by the fact that only a few D/C boundary sections exist in carbonate facies. One of these is the Palaeozoic Steinberg section, Eastern Alps, Austria. Based on detailed geochemical investigations and correlation with previously investigated sections, we propose a succession of events from the late Famennian to the Tournaisian. Both the low total rare earth element (REE) contents and the normalized REE distribution patterns indicate low terrigenous input from the praesulcata Zone to the typicus Zone. The d 13 C, d 18 O, d 34 S and total organic content (TOC) show a shift towards higher values, which correlates well with the late Famennian isotopic trends that are related to a period of active ocean circulation, cooling and increased productivity. Two isotopic shifts are present in the section: the older isotopic shift of the d 13 C values is situated at the level of the Lower to Middle praesulcata Zone, while the younger one is found at the level of the Upper praesulcata Zone. In the sulcata Zone, a sharp decrease in d 18 O values and a shift in the Ce anomaly follow. Concomitantly, a drop in the d 13 C and d 34 S values, highly variable TOC values, and the main and secondary element concentrations are interpreted to be related to a drop in primary productivity, with the recovery continuing in the crenulata Zone. In this context, the variations towards lower CaO, Sr, Rb and Ba values probably correlate with biomass variations and a transition from cooler towards warmer conditions.

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“…Retallack et al (1998) described deformed and possibly shocked quartz in P-T sediments, but a possible extraterrestrial event at this greatest mass extinction remains unproven. Several reports of spherules in Late Devonian sediments (e.g., Wang, 1992;Claeys and Cassier, 1994) been were intriguing, but detection of any clearly defined extraterrestrial component, such as a strong Ir anomaly, has remained elusive (e.g., Mc Ghee et al, 1985;Claeys et al, 1996). In my opinion, no mass extinction other than that at the K-T boundary has been conclusively linked to a strong extraterrestrial signature.…”

Section: Chemical Tracersmentioning

confidence: 99%

Tracers of the extraterrestrial component in sediments and inferences for Earth's accretion history

Kyte¹

2002

Catastrophic Events and Mass Extinctions: Impacts and Beyond

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The study of extraterrestrial matter in sediments began with the discovery of cosmic spherules during the HMS Challenger Expedition (1873-1876), but has evolved into a multidisciplinary study of the chemical, physical, and isotopic study of sediments. Extraterrestrial matter in sediments comes mainly from dust and large impactors from the asteroid belt and comets. What we know of the nature of these source materials comes from the study of stratospheric dust particles, cosmic spherules, micrometeorites, meteorites, and astronomical observations.The most common chemical tracers of extraterrestrial matter in sediments are the siderophile elements, most commonly iridium and other platinum group elements. Physical tracers include cosmic and impact spherules, Ni-rich spinels, meteorites, fossil meteorites, and ocean-impact melt debris. Three types of isotopic systems have been used to trace extraterrestrial matter. Osmium isotopes cannot distinguish chondritic from mantle sources, but provide a useful tool in modeling long-term accretion rates. Helium isotopes can be used to trace the long-term flux of the fine fraction of the interplanetary dust complex. Chromium isotopes can provide unequivocal evidence of an extraterrestrial source for sediments with high concentrations of meteoritic Cr.The terrestrial history of impacts, as recorded in sediments, is still poorly understood. Helium isotopes, multiple Ir anomalies, spherule beds, and craters all indicate a comet shower in the late Eocene. The Cretaceous-Tertiary boundary impact event appears to have been caused by a single carbonaceous chondrite projectile, most likely of asteroid origin. Little is known of the impact record in sediments from the rest of the Phanerozoic. Several impact deposits are known in the Precambrian, including several possible megaimpacts in the Early Archean.

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Geochemistry of the Frasnian-Famennian boundary in Belgium: Mass extinction, anoxic oceans and microtektite layer, but not much iridium?

Cited by 15 publications

References 34 publications

Late Frasnian–Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations

Late Frasnian–Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations

Geochemical record of Late Devonian to Early Carboniferous events, Palaeozoic of Graz, Eastern Alps, Austria

Tracers of the extraterrestrial component in sediments and inferences for Earth's accretion history

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