Frasnian Stage

(redirected from Frasnian)
Also found in: Wikipedia.

Frasnian Stage

 

the lower stage of the Upper Devonian. The Frasnian stage was identified by the Belgian geologist J. Omalius d’Halloy in 1862. At the type locality, the stage is represented by coral-reef and other limestones and by clay shales. The stage is distinguished on the basis of brachiopods, ammo-noids, and other fossils. It is divided into three (in some places, two) substages and from two to five zones. In the USSR, limestones and shales—including bituminous shales containing ammonoids and tentaculites (domanic sediments)—predominate in the Frasnian stage. In addition, brightly colored continental deposits and volcanic rocks are widespread. In many basins, the rock sequence corresponds to a marine transgression. (SeeDEVONIAN SYSTEM [PERIOD].)

References in periodicals archive ?
Quartzites, black schists with graptolites, sandstone, dolomites, blue limestone, sandy schists and ferruginous sandstone are the dominant forms, with ages ranging from the Ordovician to the Frasnian (Heddebaut, 1975; Rat and Feuillee, 1971) (Fig.
100[degrees]C, with the maximum burial episodes between the Frasnian and Lower Visean, in a time span of ca.
These are Petaloscorpio bureaui Kjellesvig-Waering, 1986 from the Frasnian Escuminac Formation of Canada (Jeram 1996) and Hubeiscorpio gracilitarsus Walossek, Li & Brauckmann, 1990 from the Frasnian of China (Walossek et al.
Depocentres were active at different times along the Lennard Shelf and Fitzroy Graben, with pronounced siliciclastic pulses occurring through the late Frasnian and Famennian.
Ooid zonation as indication for environmental conditions in a Givetian- Frasnian carbonate shelf- slope transition.
The post-Acadian succession in southern Gaspe starts with the Frasnian Miguasha Group (Brideaux and Radforth 1970; Hesse and Sawh 1992; Prichonnet et al.
The die-off climaxed at the end of the period's Frasnian stage, which lasted from around 385 million to 375 million years ago.
In 2009 Szrek also identified the same species from the so-called Kellwasser horizon (Plucki locality), uppermost Frasnian in age.
All of the rediscovered bones originally came from a Scottish site dating back to the Frasnian stage of the late Devonian period, about 370 million years ago.
The Frasnian deposits are mostly carbonates with clays and evaporates in the upper part.