|
|
Echinoderm taphonomy in the Lower Cretaceous of Štramberk
Žítt, Jiří
Taphonomy of echinoderms (echinoids, asteroids, crinoids) from the Plaňava Formation and Kopřivnice Member (Upper Valnginian - Hauterivian)is evaluated. Principal taphonomic features of echinoderm remains (disarticulation, encrustation, fragmentation, abrasion) are studied, showing special characters in both sedimentary units.
|
|
| |
|
|
Microbiostratgraphical research of the Upper Cretaceous sediments of the Gosau Formation in the Northern Calcareous Alps, Austria
Hradecká, L. ; Svobodová, Marcela ; Švábenická, L.
Isolated outcrops of the sediments of the Lower (middle Turonian-Campanian)and Upper Gosau Subgroup were biostratigraphically evaluated on the base of the presence of foraminifers, calcareous nannoplankton and palynomorphs. The oldiest sediments corresponds to Middle Turonian (Eisenbach, Weissenbachalm), upper Coniacian was found in the Finstergraben, Weissenbachalm, upper Coniacian to Santonian in the Finstergraben, Hofergraben, Schattau, Nussensee, Weisenbachalm, Campanian age in the Hühnerkogel, Mooshuben aj., Maastrichtian in the Krampen, Grünbach-Neue Welt and the youngest sedeiments of the Paleocene age in Mooshuben and Grünbach-Zweiersdorf.
|
|
| |
|
|
Late Silurian Conodont Faunas from Barrandian - selected problems
Carls, P. ; Slavík, Ladislav ; Valenzuela-Ríos, J. I.
Working on biostratigraphy of the late Silurian and of the early Devonian by means of conodont successions from Bohemia and other regions, we realize that the relevant modern literature conveys several problematic opinions and practices of identification and zonation. Silurian/Devonian boundary and adjacent strata, conodonts have been and still are important biostratigraphic tools. However, the more intense the work with them was, the more frequently mischief with their application happened. Many important taxa have been lumped; it affected negatively the precision of stratigraphic correlation. The conodont stratigraphy of late Silurian-early Devonian urgently needs revision.
|
|
|
The earliest growth stages of amphiporids and archaeocyaths - a comparison
Hladil, Jindřich
The initial growth stages of amphiporids and archaeocyaths are mutually similar to identical. They both consist of (1) rudimentary bottom disc (covered by small tubercles or septum-like bulges), (2) first chamber, (3) smooth first tube and (4) an interval with relatively rapid metamorphosis to complex adult morphologies. Probably no sponges can produce such an earliest skeletal formation that consists of the first chamber and tube, both resembling an external wall, because the typical sponge gemmules usually produce a number of cells that expand laterally very fast, forming a soft network, and it is a very different process. The great degree of similarity between the earliest growth stages of amphiporids and archaeocyaths suggests that there was a sharply separated group of "archaeocyathid-amphiporid" organisms (working name "Amphicyathida"), which was different from other corals, sponges or stromatoporoids.
|
guest ::
