Search results for "Viséan"
showing 7 items of 7 documents
First carboniferous conulariids from Niger (west Africa)
1995
Abstract Two new conulariid species, Paraconularia feldmanni sp. nov. and P. sahara sp. nov., are described from the Lower Carboniferous (Visean) Talak Formation of northern Niger. These are the first example of the genus Paraconularia to be reported from Africa and the first Carboniferous conulariids from that continent to be assigned to species level. Previously reported Carboniferous conulariids from Africa were collected from Morocco, assigned to other genera, and left in open nomenclature. Paraconularia is interpreted to have been cosmopolitan by the Early Carboniferous, and is the dominant genus in most assemblages of Carboniferous conulariids.
Late Hercynian Plate and Intraplate Processes within Europe
1987
The Hercynian orogenic belt of Europe consists of a central crystalline ridge which is accompanied on both sides by a rather unmetamorphosed foldbelt. It is speculated that the crystalline ridge represents some kind of island arc system underlain by a segment of continental crust. On both sides this island arc system was involved in subduction of oceanic crust, first of the Mideuropean Sea in the North and then of the Paleotethys in the South. When the continental areas to the north and south of the oceanic areas (North America/Northern Europe and Africa) finally got involved in the subduction processes, continent/continent collision took place on both sides of the island arc system. The tw…
Tropical marine climate during the late Paleozoic ice age using trace element analyses of brachiopods
2009
Abstract The late Paleozoic ice age can be considered an important analogue to the modern ice age, but comparisons between the two time intervals have been hampered by the difficulty of resolving climatic changes that occur over short (e.g., seasonal) time scales in the Paleozoic record. As a first step toward overcoming these limitations, this study employed Mg/Ca trace element ratios sampled across the growth bands of six specimens of the brachiopod Composita to assess differences in tropical marine mean temperature and seasonality in Visean and Moscovian time. These time intervals bracket the onset of the late Paleozoic ice age, which occurred in mid-Serpukhovian time, and thus provide a…
Productidinid brachiopods (Strophomenata, Productida), including Martinezchaconia luisae, new genus and new species of Linoproductidae, from the Carb…
2018
We describe three brachiopod species of the Suborder Productidina from the Ixtaltepec Formation, Carboniferous of the north of Oaxaca State, southern Mexico, found in peri-reef deposits. Stegacanthia bowsheri and Undaria sp. are members of the families Sentosiidae and Monticuliferidae respectively and were found in strata of the Visean (Middle Mississippian). Martinezchaconia luisae, new genus and species of the Family Linoproductidae, was recollected in Bashkirian-Moscovian (Lower-Middle Pennsylvanian) strata. The respective ages are inferred from the index species of brachiopods associated with the productidines herein described.
Morphologic variation in the P1 element of Mississippian species of the conodont genus Pseudognathodus
2018
A revision of the Austin Conodont Collection at the Natural History Museum, London, has revealed a diverse assemblage of P1 elements of Pseudognathodus . Pseudognathodus homopunctatus, Ps. lineatus, Ps. mermaidus and Ps. symmutatus are di?erentiated and a new species, Ps. posadachaconae , is de?ned from material from North Wales. The systematic of these species is updated. A revised diagnosis is provided for the genus Pseudognathodus , as well as for the species Ps. lineatus and Ps. symmutatus . The types of Ps. symmutatus cannot be differentiated from immature specimens of Ps. homopunctatus . The evolutionary relationships of Pseudognathodus species are discussed. Stratigraphic distributio…
New species of the rugose coral genus Lithostrotion Fleming in the upper Viséan from the Azrou-Khenifra Basin (Morocco)
2020
The new species Lithostrotion termieri Rodríguez & Somerville is described. It shows very large corallites of the rugose genus Lithostrotion Fleming. It has been recorded up to now only in upper Viséan rocks from the type locality, the Akrab ridge, Morocco also called Tizi Ben Zizouit by Termier & Termier (1950), who identified it as Lonsdaleia floriformis, and south-east from Tabainout, also from the Azrou-Khenifra Basin.
An Upper Mississippian echinoderm microfauna from the Genicera Formation of northern León (Carboniferous, Cantabrian Mountains, N Spain)
2020
For the first time an echinoderm microfauna is recorded from the cephalopod limestone facies (‘griotte facies’) of the lower Carboniferous (Mississippian) Genicera Fm. (Alba Fm.). The formation is widespread in the Cantabrian Mountains in NW Spain, but the ossicles are from some sections in the surroundings of the Bernesga valley in northern León. They have been derived from insoluble acetic acid residues from samples of the upper and especially of the uppermost part of the formation (Canalón Mb. and Millaró Beds). The microfauna include taxonomically treated wheel-shaped ossicles, sieve-plates and rods of holothurians, goniodonts of ophiocistioids, and ophiuroid and stenuroid skeletal elem…