Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników
Powiadomienia systemowe
  • Sesja wygasła!

Znaleziono wyników: 8

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  trylobity
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The taxonomy of simply deformed paradoxidids from the Miaolingian (Cambrian) of Słowiec Hill, Holy Cross Mountains, Poland, is revised based on morphometric analysis. The material represents two species: Acadoparadoxides slowiecensis (Czarnocki in Orłowski, 1965) and Hydrocephalus? polonicus (Czarnocki in Orłowski, 1965). A new assemblage zone based on the combined although not precisely known ranges of these two taxa is suggested replacing the previous Paradoxides polonicus Zone of Orłowski (1975, 1988, 1992a). The Acadoparadoxides slowiecensis–Hydrocephalus? polonicus Assemblage Zone corresponds to the middle and upper part of the Wuliuan Stage (lower Miaolingian).
EN
The Ordovician sedimentary succession of the Pol-e Khavand area, situated on the northern margin of the Yazd block, has important differences from those in other parts of Central Iran. It has been established that the presumably terminal Cambrian to Lower Ordovician volcano-sedimentary Polekhavand Formation, exposed in the Pol-e Khavand area, has non-conformable contact with greenschists of the Doshakh Metamorphic Complex. The succeeding, mainly siliciclastic Chahgonbad Formation contains low to moderately diverse faunal assemblages, including brachiopods, cephalopods, trilobites and tentaculitids. The Darriwilian age of the lower part of the formation is well established by the co-occurrence of brachiopod genera Camerella, Phragmorthis, Tritoechia and Yangtzeella. The associated rich cephalopod fauna is different from the Darriwilian cephalopod associations of the Alborz terrane and may show some affinity with warm water faunas of North China and South Korea. It is likely that the Mid Ordovician fauna recovered from the lower part of the Chahgonbad Formation settled in the area sometime during a warming episode in the late Darriwilian. By contrast the low diversity mid Katian brachiopod association includes only three taxa, which occur together with the trilobite Vietnamia cf. teichmulleri and abundant, but poorly preserved tentaculitids questionably assigned to the genus Costatulites. This faunal association bears clear signatures linking it to the contemporaneous cold water faunas of the Arabian, Mediterranean and North African segments of Gondwana. Four brachiopod species recovered from the Chahgonbad Formation, including Hibernodonta lakhensis, Hindella prima, Lomatorthis? multilamellosa and Yangtzeella chupananica are new to science.
EN
Seventeen taxa of exotic trilobites representing eight families are described from the olenid- and agnostoid-dominated strata of the uppermost Cambrian Series 3 and lower Furongian alum shale facies of Sweden and from glacial erratic boulders of Denmark. Only five taxa are assigned to species level, i.e., Maladioidella abdita (Salter, 1866), Olentella rara (Westergård, 1922), Pedinocephalus peregrinus (Henningsmoen, 1957), Ptychoparia pusilla (Westergård, 1922), and Westergaardella olenorum (Westergård, 1922), whereas the others are left under open nomenclature or remain unrecognized. Most are described for the first time from the Cambrian of Scandinavia. Their affinities point to a strong connection with East Gondwana, Laurentia, Kazakhstania and Siberia. Exotic trilobites appear in the succession directly after periods of very low oxygen concentration in the Alum Shale Sea; their occurrences correspond to the ranges of agnostoid arthropods in the succession and seem to be linked to global transgressive events causing an influx of cool and/or oxygen-depleted waters onto the shelf of the Baltica palaeocontinent.
EN
Deposits of the Cambrian Series 2 and 3 of the Holy Cross Mountains, comprising sandstones, and silty and clayey mudstones, are located on the Małopolska Block which is part of the Trans-European Suture Zone. Most recent geophysical data point to the proximal nature of this structural element with regard to the Baltica palaeocontinent. The trilobite assemblages are dominated by Ellipsocephalidae, generally accompanied by Holmiidae in the lower part, and by Paradoxididae in the upper part of the studied interval. They display a significant evolutionary trend, correlatable with the development of contemporary assemblages in Avalonia and Gondwana rather than those of Baltica. Discrepancies between the basement affinity and the dominant trilobites may be explained by the influence of strong larva-carrying currents from Avalonia and Gondwana.
EN
Authorship issues are clarified, new photographic documentation is provided and emended systematic descriptions are presented for the oldest Cambrian trilobite taxa from the Holy Cross Mountains (Poland). Biostratigraphic analysis of the fauna allows correlation with the traditional Holmia kjerulfi-group Zone of Scandinavia, the Callavia Zone of Britain and Newfoundland, the lower and middle part of the Sectigena Zone of Morocco and the Marianian Stage of Spain. The trilobites display a strong biogeographic signal linked with West Gondwana and Avalonia and a suggestion is made that the TESZ margin of Baltica with the Malopolska Massif was liable to currents from those areas that distributed planktonic trilobite larvae.
EN
Marine carbonates and siliciclastic rocks of the Burj Formation in Jordan include paucispecific trilobite associations of the (traditional) Lower. Middle Cambrian boundary interval. Comprehensive new material of these trilobites allows a review of their taxonomy and systematic positions as well as a refined morphological description and a reconsideration of previous interpretations of their stratigraphic position and thus the correlation of the fossiliferous beds. In addition to the classic species Kingaspis campbelli (King, 1923) and Redlichops blanckenhorni Richter and Richter, 1941, Timnaella? orientalis (Picard, 1942) and Hesa problematica Richter and Richter, 1941, the discussed trilobites include Issalia gen. nov. with Issalia scutalis gen. nov., sp. nov., Tayanaspis gen. nov. with Tayanaspis bulbosus gen. nov., sp. nov., Uhaymiria gen. nov. with Uhaymiria glabra gen. nov., sp. nov., Cambrunicornia? jafnaensis sp. nov., Myopsolenites palmeri (Parnes, 1971), M. hyperion sp. nov., and Enixus cf. antiquus (Chernysheva, 1956). Myopsolenites boutiouiti Geyer and Landing, 2004 is now regarded as a junior synonym of Myopsolenites altus (Lian and Gozalo, 1986). A detailed discussion of the correlation with a focus on global aspects provides clues for the utility of potential index fossils for the global Cambrian Series 3 and Stage 5.
EN
"Sheltered preservation" of various organisms within shells of cephalopods is a well-known phenomenon and numerous examples have been frequently reported by paleontologists from several regions but so far not from Poland. In the present paper, spectacular examples of such occurrences of different organisms preserved mainly within empty cephalopod shells are reviewed. Moreover, specimens of trilobites representing the genus Cyrtosymbole, found within the phragmocone of a clymeniid ammonoid Kalloclymenia, and disarticulated fragments of trilobites preserved in body chamber of an orthoconic nautiloid are illustrated and shortly described from the Upper Famennian of Kowala (Holy Cross Mountains, Poland).
EN
Integrated analysis of trilobite and acritarch assemblages across the traditional Lower-Middle Cambrian boundary in the Holy Cross Mountains (Poland) has documented the development of both groups in this interval. Trilobite assemblages, comprising 31 taxa (13 are revised herein) dominated by the Ellipsocephalidae, change from the protolenoid-dominated in the Lower Cambrian to the kingaspidoid-ornamentaspidoid-dominated in the Middle Cambrian, and correlate well with the Agdzian Stage of West Gondwana (Geyer and Landing 2004). Correspondence to West Gondwana and Avalonia is also evident from the presence of the associated trilobite genera, Palaeolenus, Myopsolenites, Latikingaspis, Kingaspis, Latoucheia and Orodes. The acritarch assemblages, comprising 77 taxa, indicate that their main taxonomic turnover was gradual and preceded the earliest occurrence of Paradoxides spp., as in the Spanish sections. The geological succession studied in the HCM represents part of the Cambrian strata that are generally missing in Baltica.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.