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Wyszukujesz frazę "upper Albian" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Upper upper Albian (Mortoniceras rostratum Zone) cephalopods from Clansayes (Drôme, south-eastern France)
Autorzy:
Jattiot, Romain
Lehmann, Jens
Latutrie, Benjamin
Tajika, Amane
Vennin, Emmanuelle
Vuarin, Pauline
Brayard, Arnaud
Fara, Emmanuel
Trincal, Vincent
Powiązania:
https://bibliotekanauki.pl/articles/2086664.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ammonites
Cretaceous
upper Albian
taxonomy
south-eastern France
shell chirality
amonity
kreda
alb
taksonomia
Francja południowo-wschodnia
chiralność
Opis:
We document an upper upper Albian (Mortoniceras rostratum Zone) cephalopod assemblage from Clansayes (Drôme, south-eastern France). Although fossils are rare in local exposures and in the single sampled level, a decade of intensive fossil collecting yielded 290 ammonite and 5 nautilid specimens. In total, we describe 1 species of nautilid and 24 species (within 17 genera) of ammonites, including 13 heteromorphs. Only two of these ammonite taxa were previously recorded from the upper upper Albian at Clansayes, which demonstrates the value of this fauna with regard to taxonomy, palaeobiology and palaeobiogeography. Based on morphological and biometric analyses performed on an extensive material (104 specimens), we discriminate two species for the heteromorphic ammonite genus Mariella Nowak, 1916 within the Mortoniceras rostratum Zone. In addition, we investigate shell chirality patterns in Mariella from the late Albian of southern France. Upon comparison of the Clansayes material with older material from the immediately underlying upper Albian Mortoniceras fallax Zone at the neighbouring Salazac locality, we identify an increase in the proportion of sinistral specimens. This observed increase in the frequency of sinistral Mariella specimens may hypothetically be part of a global evolutionary pattern, considering that nearly all documented younger Cenomanian Mariella (and more generally Cenomanian turrilitids) are sinistral.
Źródło:
Acta Geologica Polonica; 2022, 72, 2; 187--233
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The stratigraphy of the Upper Greensand Formation (Albian, Cretaceous) of the Isle of Purbeck, Dorset, UK
Autorzy:
Gallois, R.
Owen, H.
Powiązania:
https://bibliotekanauki.pl/articles/138644.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Upper Greensand Formation
Dorset
Isle of Purbeck
Cretaceous
Albian Stage
stratigraphy
palaeontology
ammonites
Wyspa Purbeck
kreda
stratygrafia
paleontologia
amonity
Opis:
At its maximum development in the type area on the Devon coast, the Upper Greensand Formation comprises up to 55 m of sandstones and calcarenites with laterally and stratigraphically variable amounts of carbonate cement, glauconite and chert that were deposited in fully marine, shallow-water environments. The formation is divided into three members, in ascending order the Foxmould, Whitecliff Chert and Bindon Sandstone, each of which is bounded by a prominent erosion surface that can be recognised throughout the western part of the Wessex Basin. The full thickness of the formation, up to 60 m, was formerly well exposed in cliffs in the Isle of Purbeck in the steeply dipping limb of the Purbeck Monocline. The upper part of the succession is highly condensed in comparison with the Devon succession and exhibits lateral variations over distances of hundreds of metres that are probably related to penecontemporaneous fault movements. Much of the fauna is not age-diagnostic with the result that the ages of parts of the succession are still poorly known. However, the Isle of Purbeck sections contain diverse ammonite faunas at a few stratigraphically well-defined levels that enable the succession to be correlated with that of east Devon and west Dorset.
Źródło:
Acta Geologica Polonica; 2017, 67, 3; 405-424
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The stratigraphy of the mid Cretaceous (Albian) Upper Greensand Formation of the Wessex Basin and South West England, UK
Autorzy:
Gallois, R.
Owen, H.
Powiązania:
https://bibliotekanauki.pl/articles/139028.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stratigraphy
Upper Greensand Formation
Cretaceous
Devon
Dorset
Wessex
Albian Stage
Cenomanian Stage
sequence stratigraphy
stratygrafia
formacja
kreda
dewon
alb
cenoman
Opis:
The Upper Greensand Formation, mostly capped by the Chalk, crops out on the edges of a broad, dissected plateau in Devon, west Dorset and south Somerset and has an almost continuous outcrop that runs from the Isle of Purbeck to the Vale of Wardour in south Wiltshire. The Formation is well exposed in cliffs in east Devon and the Isle of Purbeck, but is poorly exposed inland. It comprises sandstones and calcarenites with laterally and stratigraphically variable amounts of carbonate cement, glauconite and chert. The sedimentology and palaeontology indicate deposition in marginal marine-shelf environments that were at times subject to strong tidal and wave-generated currents. The formation of the Upper Greensand successions in the region was influenced by penecontemporaneous movements on major fault zones, some of which are sited over E-W trending Variscan thrusts in the basement rocks and, locally, on minor faults. Comparison of the principal sedimentary breaks in the succession with the sequence boundaries derived from world-wide sea-level curves suggests that local tectonic events mask the effects of any eustatic changes in sea level. The preserved fauna is unevenly distributed, both laterally and stratigraphically. Bivalves, gastropods and echinoids are common at some horizons but are not age-diagnostic. Ammonites are common at a few stratigraphically narrowly defined horizons, but are rare or absent throughout most of the succession. As a result, the age of parts of the succession is still poorly known.
Źródło:
Acta Geologica Polonica; 2018, 68, 2; 161-180
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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