scholarly journals The Late Cretaceous Deposits of Potassium Soils at the Gremyachinsk Field

2012 ◽  
Vol 12 (2) ◽  
pp. 50-53
Author(s):  
Ekaterina Fominichna Akhlestina ◽  
◽  
Georgiy Aleksandrovich Moskovsky ◽  
Keyword(s):  
Late Cretaceous ◽  
Cretaceous Deposits

The Gedan floristic assemblage from the Late Cretaceous deposits of the Kholchan Formation of the Okhotsk-Chukotka volcanogenic belt

Palaeobotany ◽  
2014 ◽  
Vol 5 ◽  
pp. 73-93 ◽  
Author(s):  
L. B. Golovneva ◽  
S. V. Shczepetov
Keyword(s):  
River Basin ◽  
Late Cretaceous ◽  
Middle Part ◽  
Isotopic Data ◽  
Volcanogenic Belt ◽  
Stratigraphic Position ◽  
Cretaceous Deposits

The Gedan floristic assemblage occurs from upper layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at the Gedan River in the middle part of the Arman River basin. The Gedan assemblage is composed of 6 taxa: Cladophlebis sp., Sphenobaiera sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Taxodium amguemensis (Efimova) Golovn., Metasequoia sp., Pagiophyllum sp. The similarity of the Gedan floristic assemblage with the Karamken and the Khirumki floristic assemblages from the Kholchan Formation of the Okhotsk sector of the OCVB allows us to join them in the Kholchan flora. This flora is distinct from more ancient Arman flora, which dated as the Turonian-Coniacian and from younger Ola flora, which dated as the Santonian-early Campanian. The age of the Kholchan flora is estimated as the Coniacian on the basis of stratigraphic position, presence of Podozamites, Metasequoia and Quereuxia and also isotopic data. This flora is equivalent with the Chaun flora of Central Chukotka, with the Aleeki flora from the Villigha and Toomahni Rivers interfluve and with the Ulya flora from the southern part of the Okhotsk-Chukotka volcanogenic belt.

New species of the genus Sequoia Endlicher (Cupressaceae) from the Late Cretaceous deposits of the Northeastern Russia

Palaeobotany ◽  
2015 ◽  
Vol 6 ◽  
pp. 80-95 ◽  
Author(s):  
D. A. Yudova ◽  
L. B. Golovneva
Keyword(s):  
New Species ◽  
River Basin ◽  
Late Cretaceous ◽  
Volcanic Belt ◽  
Northeastern Russia ◽  
Eastern Siberia ◽  
New Siberian Islands ◽  
Chukotka Volcanic Belt ◽  
Epidermal Features ◽  
Cretaceous Deposits

New species Sequoia ochotica Yudova et Golovn. (Pinopsida, Cupressaceae) from the Turonian-Coniacian deposits of the Arman and Chingandzha Formations of the Okhotsk-Chukotka volcanic belt is described based at morphological features of leaves and shoots. Two other Late Cretaceous species of this genus: S. minuta Sveshn. from the Vilyui River basin of Eastern Siberia and S. tenuifolia (Schmalh.) Sveshn. et Budants. from the New Siberian Islands have comparable shoot morphology, but these species were described based at epidermal features.

scholarly journals Stratigraphic and Structural Setting

1985 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. El-Arnauti ◽  
M. Shelmani
Keyword(s):  
Marine Sediments ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Late Jurassic ◽  
The West ◽  
Southeastern Part ◽  
Younger Age ◽  
History Of ◽  
Sirte Basin ◽  
Cretaceous Deposits

Abstract. INTRODUCTIONThe material which forms the basis of this project was obtained from a number of wells in the study area in Cyrenaica, the northeastern part of Libya. The study area, which is located between latitudes 25° and 33°N and between longitudes 20° and 25° E, covers some 365,750 square kilometres (see Fig. 1). The area extends from the Egyptian border in the east to the eastern flank of the Sirte Basin in the west and is part of the stable Saharan Shield.Since Precambrian time several phases of epeirogenic movements have produced troughs, horst blocks or platforms which have in turn influenced the subsequent sedimentological history of the area. In the southern and southeastern part of the study area, the basement is unconformably overlain by a thick, partially marine Palaeozoic sequence which is in turn unconformably overlain by sediments of Jurassic or younger age. The basement in the central and southwestern parts of the area is unconformably overlain by non-marine clastics of Late Jurassic and Early Cretaceous age or by marine sediments of Late Cretaceous and Tertiary age. In the eastern and northeastern section the basement is overlain by a wedge of eastward thickening marine Palaeozoic rocks which are in turn unconformably overlain by marine sediments of Late Cretaceous and Tertiary age. In the most northerly part of the northeastern region of the study area, a thick paralic sequence of Triassic, Jurassic and Early Cretaceous deposits is unconformably overlain by Late Cretaceous and Tertiary sediments.PALAEOZOICRocks of Cambro-Ordovician . . .

scholarly journals A Middle Jurassic (Bajocian) ophthalmosaurid (Reptilia, Ichthyosauria) from the Tuxedni Formation, Alaska and the early diversification of the clade

2013 ◽  
Vol 151 (1) ◽  
pp. 41-48 ◽  
Author(s):  
PATRICK S. DRUCKENMILLER ◽  
ERIN E. MAXWELL
Keyword(s):  
Northern Hemisphere ◽  
Late Cretaceous ◽  
Middle Jurassic ◽  
Evolutionary History ◽  
Data Set ◽  
Shallow Marine ◽  
Early Diversification ◽  
New Material ◽  
Northern And Southern Hemispheres ◽  
Cretaceous Deposits

AbstractOphthalmosauridae is a clade of derived thunniform ichthyosaurs that are best known from Callovian (late Middle Jurassic) to Cenomanian-aged (Late Cretaceous) deposits in both the Northern and Southern Hemispheres. Ophthalmosaurids arose prior to the Early–Middle Jurassic boundary, however, very little is known about their diversity and distribution in the earliest phase of their evolutionary history during the Aalenian–Bathonian (Middle Jurassic) interval. Here we describe new diagnostic ophthalmosaurid material from the Early Bajocian (Middle Jurassic) of Alaska. The specimen, UAMES 3411, is a partial disarticulated skull that was discovered in the Middle Jurassic Tuxedni Formation, which was deposited in shallow marine settings outboard of the then-accreting Wrangellia composite terrane. The new material is significant in that it is the first Jurassic ichthyosaur described from Alaska, one of the oldest ophthalmosaurids known and the only Middle Jurassic ophthalmosaurid described from the Northern Hemisphere. The new material adds to a rapidly growing data set on ophthalmosaurid diversity and suggests that the clade was geographically widespread by the Early Bajocian, very early in its evolutionary history.

scholarly journals New turtle remains from the Late Cretaceous of Monte Alto-SP, Brazil, including cranial osteology, neuroanatomy and phylogenetic position of a new taxon

2017 ◽  
Author(s):  
Gabriel S. Ferreira ◽  
Fabiano Vidoi Iori ◽  
Guilherme Hermanson ◽  
Max C. Langer
Keyword(s):  
Late Cretaceous ◽  
Phylogenetic Position ◽  
Phylogenetic Study ◽  
New Taxon ◽  
Early Paleocene ◽  
Cranial Osteology ◽  
Land Vertebrates ◽  
Comparative Description ◽  
High Diversity ◽  
Cretaceous Deposits

A high diversity of land vertebrates is known from the Late Cretaceous deposits of the Bauru Basin, Brazil, including at least five turtle taxa, all belonging tothe cladePodocnemidoidae. Some of the richest fossil sites of this basin are in the area of Monte Alto, which yielded several squamate, dinosaur, and crocodyliform taxa. Yet, the single turtle reported so far from this area was only briefly described. Here, we further describe that specimen, a complete but very crushed shell, as well as a partial skull, both found in outcrops of the Adamantina Formation. Comparison of the shell to other podocnemidoid taxa reveals its affinities to Roxochelys wanderleyi, a turtle originally described from that same stratigraphic unit. The comparative description of the skull and its inclusion in a phylogenetic study, supports the proposal of a new taxon representing a lineage (Peiropemydodda) so far known only from the Marília Formation of the Bauru Basin and the early Paleocene of Bolivia. The digitally reconstructed endocast and inner ear of the new taxon were also described, as not previously done fora fossil pleurodire.

scholarly journals Fossil eggshell cuticle elucidates dinosaur nesting ecology

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5144 ◽  
Author(s):  
Tzu-Ruei Yang ◽  
Ying-Hsuan Chen ◽  
Jasmina Wiemann ◽  
Beate Spiering ◽  
P. Martin Sander
Keyword(s):  
Late Cretaceous ◽  
Direct Evidence ◽  
Southern China ◽  
High Concentration ◽  
Nesting Ecology ◽  
Deep Time ◽  
Chemical Studies ◽  
Micro Analysis ◽  
Cretaceous Deposits ◽  
Chemical Evidence

The cuticle layer consisting mainly of lipids and hydroxyapatite (HAp) atop the mineralized avian eggshell is a protective structure that prevents the egg from dehydration and microbial invasions. Previous ornithological studies have revealed that the cuticle layer is also involved in modulating the reflectance of eggshells in addition to pigments (protoporphyrin and biliverdin). Thus, the cuticle layer represents a crucial trait that delivers ecological signals. While present in most modern birds, direct evidence for cuticle preservation in stem birds and non-avian dinosaurs is yet missing. Here we present the first direct and chemical evidence for the preservation of the cuticle layer on dinosaur eggshells. We analyze several theropod eggshells from various localities, including oviraptorid Macroolithus yaotunensis eggshells from the Late Cretaceous deposits of Henan, Jiangxi, and Guangdong in China and alvarezsaurid Triprismatoolithus eggshell from the Two Medicine Formation of Montana, United States, with the scanning electron microscope (SEM), electron probe micro-analysis (EPMA), and Raman spectroscopy (RS). The elemental analysis with EPMA shows high concentration of phosphorus at the boundary between the eggshell and sediment, representing the hydroxyapatitic cuticle layer (HAp). Depletion of phosphorus in sediment excludes the allochthonous origin of the phosphorus in these eggshells. The chemometric analysis of Raman spectra collected from fossil and extant eggs provides further supportive evidence for the cuticle preservation in oviraptorid and probable alvarezsaurid eggshells. In accordance with our previous discovery of pigments preserved in Cretaceous oviraptorid dinosaur eggshells, we validate the cuticle preservation on dinosaur eggshells through deep time and offer a yet unexplored resource for chemical studies targeting the evolution of dinosaur nesting ecology. Our study also suggests that the cuticle structure can be traced far back to maniraptoran dinosaurs and enhance their reproductive success in a warm and mesic habitat such as Montana and southern China during the Late Cretaceous.

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