Search results for "Devonian"
showing 10 items of 77 documents
LOCHKOVIAN TO PRAGIAN (LOWER DEVONIAN) NERITIC OSTRACODES FROM NIGÜELLA (ZARAGOZA, IBERIAN CHAINS, NE SPAIN)
2021
Lochkovian and Pragian ostracodes from the area of Niguella (Iberian Chains), which is a key area for supra-regional correlation in the Early Devonian, are described for the first time. 12 ostracode taxa from the sections Ni4 and Ni2 could be identified. The silicified ostracodes of Eifelian Ecotype are low in biodiversity, have few individuals, and are comparatively poorly preserved. Characteristic taxa of the Devonian occur. Thus, the faunas show general relations to most European Early Devonian ostracode faunas. Closer relations exist to the Eastern Guadarrama. Polyzygia kroemmelbeini LeFevre & Weyant, 1967 and P. grekoffi Weyant, 1980 are found in the basal Pragian for the first time. B…
A NEW EARLY DEVONIAN THELODONT FROM CELTIBERIA (SPAIN), WITH A REVISION OF SPANISH THELODONTS
2006
: A revision of thelodont scales from the Lower Devonian of the Iberian Chains enables their grouping into two taxa: Turinia pagei and T. nachoi sp. nov. These taxa are clearly distinguishable by morphological and histological features; they also have a different stratigraphic range (T. pagei is restricted to Lochkovian strata, whereas T. nachoi sp. nov. occurs within lower–middle Pragian rocks). The new species is represented by head, transitional (cephalopectoral) and trunk scales.
Braquiópodos devónicos de la Cordillera Cantábrica (Norte de España). 12) Ferronirhynchia nuevo género de rinconélido (Trigonirhynchiidae) del Emsien…
2021
The taxonomic status of the subfamily Trigonirhynchiinae is discussed based on the morphological features, together with the geographic and the stratigraphic distribution of the type genus Trigonirhynchia Cooper. The new genus, Ferronirhynchia n. gen., including the type species F. pulgari n. sp., is proposed. The new taxon, close to Trigonirhynchia , occurs in upper Emsian beds of the Moniello Formation, in Asturias, serotinus/patulus conodont zones, Faunal Intervals 14 to 16a. The ontogeny and palaeoecology of F. pulgari are analyzed. Growth of the new species is bicyclic. Juvenile forms are low and biconvex displaying sharp commissures. Adult forms are high, dorsi-biconvex, ge…
Late Devonian (Famennian) chondrichthyes from Mexico
2019
The Paleozoic vertebrate fossil record from Mexico is very scarce and strongly biased by rock exposure, composed mainly of upper Paleozoic (Carboniferous and Permian) outcrops (e.g., Sánchez-Zavala et al., 1999; Poole et al., 2005; González- Rodríguez et al., 2013). In particular, the Mexican Paleozoic fish fossil record comprises a few isolated chondrichthyan scales and some semiarticulated symphysial tooth whorls belonging to the iconic shark Helicoprion, with ages ranging from the Late Carboniferous to the early Permian. The first reported Paleozoic fish from Mexico belongs to a semiarticulated symphysial tooth whorl of Helicoprion mexicanus from the Permian of Coahuila, near Las Delicia…
Sucesión de Polygnátidos (Conodontos) del Emsiense (Devónico Inferior) en los Pirineos Centrales Españoles
2011
A comprehensive conodont study of five sections of Emsian age, carried out in the Spanish Central Pyrenees, has revealed an important succession of polygnathids that can be used for identifying basal boundaries of globally recognized biozones. This succession consists of Polygnathus excavatus excavatus, Po. gronbergi, Po. nothoperbonus, Po. mashkovae, Po. laticostatus, and the new species Polygnathus luciae that allows the identification of the excavatus, nothoperbonus and laticostatus Zones. The nothoperbonus Zone is further subdivided into Lower and Upper nothoperbonus subzones, relying upon the lowest occurrence of Po. mashkovae. These biostratigraphic data from the Spanish Central Pyren…
Vertebrate and Miospore Assemblages from the Famennian of North Timan (Upper Devonian, Russia)
2014
The Upper Devonian vertebrate and miospore assemblages from the Volonga River section of the upper part of the Pokayama Formation from North Timan are described for the first time. The middle Famennian age of the unit is confirmed by miospore data. The correlation of some East European sections is discussed.
Upper Pleistocene biostratigraphy and traces of glaciotectonics at the Satiki site, western Latvia
2007
Structural, lithological, palynological and plant macroremain investigations of test-boring cores and gravel pit walls at the Satiki site suggest that gyttja and sandy gyttja units of basin sediments were deposited during the Felicianova (Eemian) Interglacial. A pollen diagram reflects the characteristic forest succession of the Eemian Interglacial: Betula, Pinus, Ulmus, Corylus, Quercus, Fraxinus, Tilia, Carpinus, Picea and Pinus. Forests of broadleaved trees and thermophilous plants dominated in the surroundings of the lake during the interglacial climatic optimum. The basin sediments contain a large number of warmth-demanding water plants such as Salvinia natans and Trapa sp. Paleobotani…
Palaeozoic evolution of the North Tianshan based on palaeomagnetic data – transition from Gondwana towards Pangaea
2017
We present new palaeomagnetic data for Cambrian and Ordovician volcanic and sedimentary rocks from the Kyrgyz North Tianshan (NTS) and review available data from the southwestern Central Asian Orogenic Belt (CAOB) to elucidate the tectonic history and evolution of this region during the early Palaeozoic. We observed a coherent evolution of the NTS and the Kazakhstan continent (or Kazakhstania) with a constant northwards movement between the Cambrian and Devonian at ∼5 cm/a. After the northwards movement ceased in the Devonian, the accreted terrane assemblage of Kazakhstania occupied a stable latitudinal position at ∼30°N until the final amalgamation of Eurasia occurred in the late Carbonife…
Zircon ages and Hf isotopic compositions of plutonic rocks from the Central Tianshan (Xinjiang, northwest China) and their significance for early to …
2014
We present new zircon ages and Hf-in-zircon isotopic data for plutonic rocks and review the crustal evolution of the Chinese Central Tianshan (Xinjiang, northwest China) in the early to mid-Palaeozoic. The Early Ordovician (ca. 475–473 Ma) granitoid rocks have zircon eHf(t) values either positive (+0.3 to +9.5) or negative (−6.0 to −12.9). This suggests significant addition of juvenile material to, and coeval crustal reworking of, the pre-existing continental crust that is fingerprinted by numerous Precambrian zircon xenocrysts. The Late Ordovician–Silurian (ca. 458–425 Ma) rocks can be assigned to two sub-episodes of magmatism: zircon from rocks of an earlier event (ca. 458–442 Ma) has neg…
Sinistral transport along the Trans-European Suture Zone: detrital zircon–rutile geochronology and sandstone petrography from the Carboniferous flysc…
2010
AbstractThe Lower Carboniferous flysch of the Istanbul Zone in Turkey is an over 1500 m thick turbiditic sandstone–shale sequence marking the onset of the Variscan deformation in the Pontides. It overlies Lower Carboniferous black cherts and is unconformably overlain by Lower Triassic continental sandstones and conglomerates. The petrography of the Carboniferous sandstones and the geochronology and geochemistry of the detrital zircons and rutiles were studied to establish the provenance of the clastic rocks. The sandstones are feldspathic to lithic greywackes and subgreywackes with approximately equal amounts of quartz, feldspar and lithic clasts. The amount of quartz and lithic fragments d…