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Wyszukujesz frazę "Kayenta Formation" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Magnetostratigraphy and paleopoles of the Kayenta Formation and the Tenney Canyon Tongue
Autorzy:
Steiner, M.
Tanner, L.
Powiązania:
https://bibliotekanauki.pl/articles/2077334.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Pliensbachian magnetostratigraphy
Kayenta Formation
paleopole
J-1 cusp
North America
formacja Kayenta
szpic J-1
Ameryka Północna
Opis:
The Kayenta Formation is the third in a series of stratigraphic units making up the Glen Canyon Group that were sampled along US Hwy 89 in southern Utah. The Kayenta is dominantly reversed polarity with a number of very short normal polarity intervals. Above the Kayenta and interbedded in the Navajo Sandstone is the Tenney Canyon Tongue of the Kayenta Formation. The lower half of the Tenney Canyon Tongue was also sampled and is dominantly normal polarity with three short reversed polarity intervals. The dominantly reversed magnetostratigraphy of the Kayenta appears to match that of Early Pliensbachian polarity interval “e-Pli R.” The dominance of normal polarity of the Tenney Canyon Tongue suggests that the Tenney Canyon may have been deposited in the upper half of the Pliensbachian polarity interval “ePli-N.” The suggested polarity matches indicate that the Kayenta and Tenney Canyon Tongue strata are 187–190 Ma in age. The paleopoles of the two units are statistically identical. The combined data of the Kayenta-Springdale-Whitmore Point show that the J-1 cusp terminated before the deposition of the Kayenta Formation. The North American continent/pole returned to its Late Triassic position during/after Springdale time, apparently along the same path used to reach the apex of the J-1 cusp.
Źródło:
Volumina Jurassica; 2014, 12, 2; 31--38
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The cranial anatomy of the Early Jurassic turtle Kayentachelys aprix
Autorzy:
Sterli, J.
Joyce, W.G.
Powiązania:
https://bibliotekanauki.pl/articles/22757.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
cranial anatomy
Cryptodira
Testudines
Jurassic
Early Jurassic
turtle
Kayentachelys aprix
evolution
fossil record
Kayenta Formation
Arizona
paleontology
systematics
Opis:
The fossil turtle Kayentachelys aprix is known from Early Jurassic sediments of the Kayenta Formation, Arizona, USA. The detailed description of this taxon’s cranium offered in this paper demonstrates that this turtle presents a mixture of primitive and derived character states. Among others, the presence of an interpterygoid vacuity, a basipterygoid process, a prootic that is exposed in ventral view, and a foramen posterius canalis carotici interni that is formed entirely by the basisphenoid are generally considered primitive for turtles. On the other hand, the presence of an undivided apertura narium, a well developed cavum tympani, an incipient cavum postoticum, and an unpaired vomer are considered to be derived. Kayentachelys aprix has previously been hypothesized to be the oldest stem cryptodiran turtle because of the presence of a flat, vertical plate on the processus pterygoideus externus, and the presence of a processus trochlearis oticum. However, the presence of these characters cannot be confirmed in the available specimens. Other putative stemcryptodiran characters, such as the prefrontal−vomer contact and the presence of an epipterygoid, are herein corroborated as being symplesiomorphies, because they generally appear to be present in basal turtles.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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