Ostracods Late Devonian mass extinction: the Schmidt quarry parastratotype (Kellerwald, Germany)

Abstract

' Labomtoire de micropaMont&gie, dipatiement de gBologie s6dimentaire, l:nit~e&t! Paris 6 T25-15, 4lf, case 104-4, 4, place Jussieu. 75252 Parts cedex 0 5, France ABSTKACT Sixty-eight ostracod species have been recognized (the benthonic one for the first time) close to the Frasnian/Famennian boundary in the Schmidt quarry parastratotype. In the Late Frasnian, ostracods belong to an assemblage of the Eifelian ecotype and to the Myodocopid ecotype. In the base of the Famcnnian. they belong exclusively to the Eifelian ecotype. The oxygen content of the bottom waters during the deposition of the Upper Kellwasser horizon was highly unstable whereas this horizon was known to be anoxic. The Late Devonian mass extinction, probably the second in order of magnitude during the Phanerozoic, took place in the last 5 cm of the Upper Kellwasser horizon. Twelve ostracod species recognized in the Schmidt quarry survived this event.

Extent and duration of marine anoxia during the Frasnian–Famennian (Late Devonian) mass extinction in Poland, Germany, Austria and France

“…At Steinbruch Schmidt the variable ostracod content of the Upper Kellwasser Horizon suggests large fluctuations from aerobic to anaerobic facies (Casier & Lethiers, 1998), although reported enrichments in chalcophile trace metals from this section indicate persistent euxinicity (Goodfellow et al 1989). The aerobic ostracod assemblages may be allochthonous.…”

The Frasnian–Famennian biotic crisis: How many (if any) bolide impacts?

“…Nevertheless, overall fertile, although maybe highly unstable, surface-water nutrient levels seem to the most likely setting for the KW timespan (Becker and House 1994;Paris et al 1996;Hallam and Wignall 1997, p. 87). The changes in productivity dynamics can be supported by very variable oxygenation of the bottom waters during the Upper KW hypoxic interval, postulated by Casier and Lethiers (1998). Kasig and Wilder (1983) determined firstly the key role of increased plankton production in the F-F biocrisis, attributed to enriched trophic resources in shelf habitats due to exogenous factors, especially the progressive land colonization by vascular plants and increased soil development.…”

Late Devonian global ostracod palaeobiogeography

“…), F‐F (Raup & Sepkoski ; Sepkoski ; Casier et al . , ; Casier & Lethiers ) and D‐C (Casier & Préat ; Casier et al . ) events.…”

“…Lethiers & Casier ; Casier et al . , ,b, , ; Casier & Lethiers ; Wang & McKenzie ) have been well studied. However, there have been only a few studies on the palaeogeography of Devonian ostracods (e.g.…”

“…The main factors controlling the distribution of marine ostracod faunas include salinity, bathymetry, temperature, hydrodynamics and nutrients (Casier & Olempska 2008a;Olempska & Belka 2010). The Devonian was a prosperous period of ostracods and also an age of major tectonic and bioenvironmental events in the world, such as the Hercynian and Acadian orogenies (Young 1987;Young et al 2010), F-F (Raup & Sepkoski 1982;Sepkoski 1990;Casier et al 1996Casier & Lethiers 1998b) and D-C (Casier & Pr eat 2003;Casier et al 2004) events. As such, ostracods may offer special insights into the characteristics and evolution of the Devonian global bioenvironments.…”