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Wyszukujesz frazę "ammonites" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Turonian-Coniacian (Upper Cretaceous) of the Babadag Basin (North Dobrogea, Romania) : integrated biostratigraphy and microfacies succession
Autorzy:
Lodowski, Damian Gerard
Walaszczyk, Ireneusz Piotr
Grădinaru, Eugen
Powiązania:
https://bibliotekanauki.pl/articles/2058617.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
microfacies
petrology
inoceramids
ammonites
foraminifera
palaeoenvironment
Opis:
The Upper Turonian to Middle Coniacian (Upper Cretaceous) succession of the Babadag Basin (North Dobrogea, Romania) constitutes an apparently continuous fossiliferous carbonate succession. The presence of moderately rich inoceramid, ammonite and foraminiferal assemblages allows for the application of a precise biostratigraphic subdivision. The palaeoenvironmental conditions and evolution of the Babadag Basin during the Late Turonian-Middle Coniacian are inferred using microfacies analysis and foraminiferal spectra. Together, these suggest the Turonian-Coniacian Badabag Basin reflects relatively shallow-water conditions in a near-shore environment, punctuated by two regression events in the Late Turonian and in the Middle Coniacian.
Źródło:
Geological Quarterly; 2019, 63, 1; 39--64
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudothurmanniid ammonites from quarries near Lietavská Lúčka and their stratigraphical significance (Late Hauterivian, Central Western Carpathians, Slovakia)
Autorzy:
Vašiček, Z.
Malek, O.
Powiązania:
https://bibliotekanauki.pl/articles/2060607.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
ammonites
taxonomy
stratigraphy
Hauterivian
Western Carpathians
Opis:
Pseudothurmanniid ammonites within Upper Hauterivian calcareous deposits are present in quarries on Polomec Hill near the village of Lietavská Lúčka, Slovakia. These deposits belong to the Mráznica Formation of the Krížna Nappe that is a part of the Fatricum Unit in the Central Western Carpathians. Nine ammonite species are described in detail, one of which, Binellicerasmichalíki, is new. The species identified indicate the Upper Hauterivian Balearis and Ohmi ammonite zones. The zone of the uppermost Hauterivian, Catulloi Zone, is not documented as far as pseudothurmanniid ammonites are concerned. The lackof developmentally younger representatives of the pseudothurmanniid ammonites neitherin the studied locali ty, nor in other Slovak locali ties, is explained by marked changes in the northern Tethyan margin in Europe duri ng the latest Hauterivian.
Źródło:
Geological Quarterly; 2017, 61, 3; 613--631
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Palaeobiogeography, palaeoecology, and sequence stratigraphy of the Upper Jurassic carbonate succession of the Lar Formation, central Alborz Zone, Iran
Autorzy:
Saleh, Zahra
Reháková, Daniela
Powiązania:
https://bibliotekanauki.pl/articles/27324245.pdf
Data publikacji:
2023
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Upper Jurassic
microfacies
foraminifera
ammonites
calcareous dinoflagellates
biostratigraphy
sequence stratigraphy
Alborz Zone
Iran
Opis:
Foraminifera, ammonites, and calcareous dinoflagellates were used for stratigraphy and, together with microfacies, for the assessment of the palaeoenvironmental conditions of the Upper Jurassic deposits in the central Alborz Zone of northern Iran. The Lar Formation (Lar Fm.) in the Polur section is of latest Oxfordian to early Kimmeridgian age. The ammonite Subnebrodites planula and the calcareous dinoflagellate Colomisphaera nagyi have been introduced as new biomarkers of the lower Kimmeridgian in the central Neo-Tethys. The distribution of calcareous dinoflagellates reflects possible dispersal routes along a narrow seaway between the western Neo-Tethys and the Alborz Zone in the central Neo-Tethys. The Terebella-Crescentiella associations of the Lar Fm. represent a low-energy setting under dysoxic conditions in the Central Neo-Tethys Ocean. The benthic foraminiferal assemblages in this formation show a high dominance of infaunal taxa and r-selected strategists. This assemblage is reminiscent of eutrophic conditions and low oxygen levels in the lower part of the Lar Fm. Good preservation of the hexactinellid sponges in the upper part of the Lar Fm. also indicates an oxygen-minimum zone. Three third-order depositional sequences can be distinguished in the study area based on six microfacies. Depositional sequence 1 (DS1) is composed mainly of argillaceous limestone and medium- to thick-bedded limestone, corresponding to an outer ramp-to-middle ramp environment. Depositional sequence 2 (DS2) comprises breccia limestone and thick-bedded limestone facies in its lower part and thin-bedded limestone to massive limestone in its upper part. The breccia limestone facies may be associated with subaerial exposure and reworking of previously deposited sediment during a relative sea level fall. The thin-bedded limestone to massive limestone of DS2 consists mainly of bioclastic mudstone to wackestone (outer ramp). These represent an deep-water outer homoclinal ramp facies. Depositional sequence 3 (DS3) consists mainly of massive limestone to thick-bedded limestone with a bioclastic peloidal microbial Crescentiella packstone (middle ramp). The relative stratigraphic positions of DSs1–3 and sequence boundaries in the uppermost Oxfordian to lower Kimmeridgian of the Polur area show a fair match to the upper Oxfordian to lower Kimmeridgian sequences (JOx7, JOx8, JKi1 and JKi2) on the global sea level curve.
Źródło:
Geological Quarterly; 2023, 67, 2; art. no. 15
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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