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Wyszukujesz frazę "Berriasian stages" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The Jurassic-Cretaceous boundary in Boreal Russia : radiolarian and calcareous dinoflagellate potential biomarkers
Autorzy:
Vishnevskaya, V. S.
Powiązania:
https://bibliotekanauki.pl/articles/2060606.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Tithonian stages
Berriasian stages
radiolarians
calcareous dinoflagellates
Tethys
boreal
Volgian
Opis:
The International Berriasian Working Group (ISCS) suggested primary and secondary marker “datums” to fix the basal Berriasian boundary and thus to detine the Jurassic-Cretaceous boundary (Wimbledon et al., 2011, 2013). Two primary markers Calpionella, as well as calcareous nannoplankton, are practically unknown in the Boreal Realm. Testing and calibration of these markers, as well as of fossils of radiolarians and other signals, in the most complete sections, were declared as an important task for the near future. In the Tethys, the Jurassic-Cretaceous boundary based on radiolarians falls inside zone UAZ 13 of Baumgartner et al. (1995), whereas in the palaeo-Pacific it corresponds to the boundary between zones 4 and 5 of Pessagno et al. (2009), and in boreal Siberia it probably falls between the biohorizons of Parvicingula haeckeli and P. khabakovi. The radiolarian events at the Jurassic-Cretaceous boundary in the boreal successions of Russia can be proposed to be used as an additional biomarker to help develop new integrated boundary criteria. Thus, as the first appearance of the zonal species Calpionella alpina, which defines the Jurassic and Cretaceous boundary, coincides with the first occurrence of the calcareous dinocyst zonal species Stomiosphaerina proxima (Reháková, 2000), it is logical to propose a calcareous dinoflagellate, widely represented in the Upper Jurassic-Lower Cretaceous Bazhenovo Formation of Siberia, as a secondary marker.
Źródło:
Geological Quarterly; 2017, 61, 3; 641--654
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The proposal of a GSSP for the Berriasian Stage (Cretaceous System): Part 2
Autorzy:
Wimbledon, William A.P.
Reháková, Daniela
Svobodová, Andrea
Elbra, Tiiu
Schnabl, Petr
Pruner, Petr
Šifnerová, Krýstina
Kdýr, Šimon
Frau, Camille
Schnyder, Johann
Galbrun, Bruno
Vaňková, Lucie
Dzyuba, Oksana
Copestake, Philip
Hunt, Christopher O.
Riccardi, Alberto
Poulton, Terry P.
Bulot, Luc G.
De Lena, Luis
Powiązania:
https://bibliotekanauki.pl/articles/2060930.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Cretaceous
GSSP
biostratigraphy
magnetostratigraphy
Vocontian Basin
Berriasian stages
Kreda
biostratygrafia
magnetostratygrafia
Opis:
In part 1 of this work we discussed the possibilities for the selection of a GSSP for the Berriasian Stage of the Cretaceous System, based on prevailing practical methods for correlation in that J/K interval, traditional usage and the consensus over the best boundary markers that had developed in the last forty years. This consensus has developed further, based on the results of multidisciplinary studies on numerous sites over the last decade. Here in Part 2 we give an account of the application of those results by the Berriasian Working Group (ISCS), and present the stratigraphic evidence that justifies the selection of the locality of Tré Maroua (Hautes-Alpes, SE France) as the proposed GSSP. We describe a 45 m-thick section in the Calcaires Blancs vocontiens – that part of the formation covering the calpionellid Chitinoidella, Remanei. Intermedia, Colomi, Alpina, Ferasini, Elliptica and Simplex biozones. The stratigraphic data collected here has been compiled as part of a wider comparative study of complementary Vocontian Basin sites (with localities at Charens, St Bertrand, Belvedere and Le Chouet). Evidence from Tré Maroua thus sits in this substantial regional biostratigraphic and magnetostratigraphic context. For the purposes of the GSSP definition, here we particularly concentrate on the unbroken sequence and biotic markers in the interval immediately below the boundary, the Colomi Subzone (covering circa 675,000 years), and immediately above, the Alpina Subzone (covering circa 725,000 years). Particularly significant fossil datums identified in the Tré Maroua profile are the primary basal Berriasian marker, the base of the Alpina Subzone (a widespread event marked by dominance of small Calpionella alpina, with rare Crassicollaria parvula and Tintinopsella carpathica): the base of the Berriasian Stage is placed at the base of bed 14, which coincides with the base of the Alpina Subzone. Secondary markers bracketing the base of the Calpionella Zone are the FOs of the calcareous nannofossil species Nannoconus wintereri, close below the boundary, and the FO of Nannoconus steinmannii minor, close above. The Tithonian/Berriasian boundary level occurs within M19n.2n, in common with many documented sites, and is just below the distinctive reversed magnetic subzone M19n.1r (the so-called Brodno reversal). We present data which is congruent with magnetostratigraphic and biostratigraphic data from other key localities in France and in wider regions (Le Chouet, Saint Bertrand, Puerto Escaño, Rio Argos, Bosso, Brodno, Kurovice, Theodosia…), and thus the characteristics and datums identified at Tré Maroua are key for correlation and, in general, they typify the J/K boundary interval in Tethys and connected seas
Źródło:
Volumina Jurassica; 2020, 18, 2; 121-160
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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