نتایج جستجو برای: aptian

تعداد نتایج: 457  

Journal: :Cretaceous Research 2023

The Aptian sedimentary deposits of the Castro Urdiales area in north Spain record an episode disoxia/anoxia which postdates Oceanic Anoxic Event 1a (OAE 1a). Carbonate platform and overlying facies are analysed for stratigraphy, sedimentology, total organic carbon isotopes. Lower shallow-water limestones covered by deeper-water marlstones organic-carbon-rich black lutites lower to upper Aptian,...

Journal: :International Journal of Plant Sciences 2013

Journal: :Frontiers in Earth Science 2023

High-amplitude changes in sedimentary δ 13 C characterize the Cretaceous system and have been proven useful for supra-regional chemostratigraphic correlation. In Cretaceous, these perturbations indicate large shifts between global carbon reservoirs that are usually caused by volcanic activity of igneous provinces, widespread deposition thick organic carbon-rich sequences and/or orbital paramete...

Journal: :Molecular phylogenetics and evolution 2016
Brent A Berger Ricardo Kriebel Daniel Spalink Kenneth J Sytsma

We examine the eudicot order Myrtales, a clade with strong Gondwanan representation for most of its families. Although previous phylogenetic studies greatly improved our understanding of intergeneric and interspecific relationships within the order, our understanding of inter-familial relationships still remains unresolved; hence, we also lack a robust time-calibrated chronogram to address hypo...

2015
Ignacio Díaz-Martínez Xabier Pereda-Suberbiola Félix Pérez-Lorente José Ignacio Canudo

BACKGROUND Large ornithopod tracks are known from the Upper Jurassic to the uppermost Cretaceous rocks of all continents but Antarctica. They include the tracks historically called Iguanodon footprints, iguanodontid footprints, hadrosaur/hadrosaurid footprints, and other large ornithopod tracks that have been used to define ichnotaxa. More than 40 ichnospecies based on large ornithopod tracks h...

Journal: Geopersia 2015

The investigated section cropping out in Kuh-e-Banesh, Zagros basin (southern Iran) is represented by limestone, Cherty beds and marllevels bearing abundant Planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. For the first time, well to moderatelypreserved forms of Planktonic foraminifera have been extracted from black shale and marls levels. Extracted biota was studied wit...

2005
Garry D. Karner Donna J. Shillington

High core recovery at Ocean Drilling Program (ODP) Leg 210, Site 1276, provided a high-resolution porosity-depth relationship and an equally impressive age-depth model based on first and last occurrences of microfossils. Site 1276 was drilled over transitional crust in the Newfoundland nonvolcanic margin, offshore Canada, between known continental crust on the west and apparent oceanic crust on...

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