Search results for "Permian"
showing 10 items of 89 documents
Saxonagrion minutus nov. gen. et sp., the oldest damselfly from the Upper Permian of France (Odonatoptera, Panodonata, Saxonagrionidae nov. fam.)
1999
Abstract Saxonagrion minutus nov. gen. et sp. was found in the Saxonian (Salagou Formation) of the Lodeve basin. It is the oldest and the first record of the modern infra-order Panodonata in the Palaezoic (Upper Permian of France). The present discovery supports the hypothesis concerning the persistance of many groups of Odonatoptera through the Permo-Triassic boundary.
The microstructural variability of the intercentra among temnospondyl amphibians
2014
The histology of the vertebral centrum of the morphologically diverse Temnospondyli is poorly known. In this study, the variability of the histological framework of various taxa from several Permian and Triassic localities was investigated for the first time. Twelve intercentra, forming the anterior part of the diplospondylous centra of temnospondyls, were examined histologically. The intercentra of all studied taxa share a highly vascularized cortex on the ventro-lateral side and primary and secondary trabecular, endochondral bone on the dorsal side. A high variability is present, among others, within the arrangement of the vascular cavities, the density of the trabeculae and the distribut…
Parainoceramyan. gen. forParainoceramusCox, 1954 (exVoronetz, 1936)partim(Bivalvia, Jurassic)
2015
Several Jurassic pterioid bivalve species have been referred to Parainoceramus Cox by different authors, yet this has proved inadequate because the meaning of such genus has been compounded by nomenclatural and idiomatic problems, as well as misinterpretations. Hence, the new genus Parainoceramya is here proposed to accommodate several species previously referred to Parainoceramus, with Crenatula ventricosa J. de C. Sowerby as its type. Permian species originally assigned to Parainoceramus, including the type species, are referred to the genus Kolymia Likharev. All species attributed to Parainoceramus s.l. are reviewed and the new genus is compared with related genera. As here understood, t…
Ichnocoenoses à Isopodichnus furcosus nov. ichnosp. dans le Permien du Bassin de Lodève (Massif Central, France)
1994
Resume Une nouvelle ichnoespece Isopodichnus furcosus est decrite. Elle represente des traces de repos faites probablement par des Branchiopodes notostraces. Frequente dans les formations de Rabejac et du Salagou du bassin de Lodeve, elle est caracterisee par l'existence de structures paires generalement bifides, parfois trifides. Celles-ci pourraient correspondre a l'empreinte des premiers appendices thoraciques, longs et ramifies chez les Triopsides ou Apodides a qui est attribuee Isopodichnus furcosus nov. ichnosp. La presence de niveaux a Isopodichnus furcosus nov. ichnosp. dans les formations rouges supraconglomeratiques de la serie permienne renforce la these du developpement de l'ari…
Phaenocompsopogon pustulatus n.gen.n. sp., a calcareous alga from the lacustrine rotliegend of the Saar-Nahe Basin (SW-Germany)
1992
Phaenocompsopogon pustulatus n. gen. n. sp. is a calcareous freshwater alga, probably of rhodophycean affinity. The fossils are mainly known from one locality in the Lower Permian of the Saar-Nahe Basin. The algal remains form a packstone in the Reckweilerhof-Bank of the Altenglan Formation. The simple thallus branches irregularly y-shaped and is covered with abundant pustules. An axial canal is characteristic, as are distinct cell features of an inner and outer cortex surrounding a structureless medulla. Most fossils are silicified and often three-dimensionally preserved. The algae lived in a wave-dominated environment, probably in offshore shallow water. The limited occurrence suggests sp…
Morphology and function of the sutures in the dermal skull roof of Discosauriscus austriacus Makowsky; 1876 (Seymouriamorpha; Lower Permian of Moravi…
1995
Abstract Sutural patterns in the dermal skull roof were among others studied in Discosauriscus austriacus (Seymouriamorpha) and Onchiodon labyrinthicus (Temnospondyli). Main sutural structures are defined as lamellae; shelves; vertical walls; and grooves. These types have different functional manifestations. The basic pattern is described for Discosauriscus austriacus. Similarities of patterns in taxa not closely related are most likely a result of convergence. Intraspecific variability is generally low but can be observed during ontogeny. The patterns of subjacent areas in Eusthenopteron foordi (Osteolepiformes) are very similar to Discosauriscus austriacus. It is shown that sutural morpho…
Bimodal sill emplacement from an inhomogeneous source: a case study of olivine-gabbronorite and diabase with Ni-Cu sulphides in a sill within Permian…
2009
A small outcrop of mafic rocks, located between the Permian-Triassic sediments of the Cenozoic tectonic unit of the Maghrebian chain in Western Sicily, is an olistolith made up of olivine gabbronorite within diabase. Textures, microprobe analyses, and major and trace element geochemistry confirm the co-genetic nature of the various rocks: the gabbronorite is the result of olivine and orthopyroxene accumulation, with interstitial clinopyroxene and plagioclase, in a framework of a gabbrodioritic diabase. At least two stages of magmatic crystallisation during ascent in the continental crust are described, on the basis of reconstructed conditions of T, P and XH2O. The primitive magma was recons…
New lithostratigraphy for the Cantabrian Mountains: A common tectono-stratigraphic evolution for the onset of the Alpine cycle in the W Pyrenean real…
2019
The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary ph…
The Palaeomagnetism of the Permian Rocks of the Black Forest, Germany
1972
Summary Palaeomagnetic measurements made upon Permian samples from the Black Forest, Odenwald and Pfalzerwald (excluding those measurements on samples from the Schopfheim basin) are consistent with those from north-western Europe. The virtual pole based upon 18 sites is 174.9°E. 48.4N. The measurements made on the fine-grained shales and mudstones from the Schopfheim basin are significantly different from the preceding. Since incorrect age assignment, sampling, components of secondary magnetic and tectonic effects can be excluded, the difference is attributed to incomplete removal of the effects of secular variation. The Scharfenstein massif previously regarded as Permian, was found to have…
Late Paleozoic Ice Age glaciers shaped East Antarctica landscape
2019
International audience; The erosion history of Antarctica is fundamental to our understanding of interlinks between climate and glacier dynamics. However, because of the vast polar ice sheet covering more than 99% of Antarctica land mass, the continental surface response to glacial erosion remains largely unknown. Over the last decade the subglacial topography of Antarctica has been imaged by airborne radar surveys. These studies revealed high and complex sub-glacial relief in the core of the East Antarctic shield, interpreted as resulting from rifting episodes and low long-term erosion rates, or repeated large-scale glacial retreats and advances. In East Antarctica, thermochronology studie…