نتایج جستجو برای: foraminifera

تعداد نتایج: 4350  

Journal: :Anais da Academia Brasileira de Ciencias 2007
Wanessa S Marques Eldemar de A Menor Alcides N Sial Valdir A V Manso Satander S Freire

Specimens of Recent foraminifera of Amphistegina radiata, Peneroplis planatus and Globigerinoides ruber, from fifty samples of surface sediments of the continental margin of the State of Ceará, Brazil, have been analyzed for carbon and oxygen isotopes to investigate oceanographic parameters and determine the values of delta18O of the oceanic water. From a comparison between values of delta18O o...

2005
JÉRÔME FLAKOWSKI IGNACIO BOLIVAR JOSÉ FAHRNI JAN PAWLOWSKI

Molecular phylogenies of foraminifera are commonly inferred from the small subunit rRNA (SSU) genes, which can easily be obtained from single cells isolated from environmental samples. The SSU phylogenies, however, are often biased by heterogeneity of substitution rates, and their resolution of higher level relationships is often very low. The sequences of protein-coding genes provide an import...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Shmuel Bentov Colin Brownlee Jonathan Erez

Foraminifera are unicellular organisms that inhabit the oceans in various ecosystems. The majority of the foraminifera precipitate calcitic shells and are among the major CaCO(3) producers in the oceans. They comprise an important component of the global carbon cycle and also provide valuable paleoceanographic information based on the relative abundance of stable isotopes and trace elements (pr...

Journal: Geopersia 2016
Farzaneh Barani Felix Schlagintweit, Koorosh Rashidi

The larger benthic foraminifera Gyroconulina columellifera Schroeder & Darmoian, 1977 (type-locality: Maastrichtian Aqra Formation of Iraq) is described for the first time from two sections of the Maastrichtian Tarbur Formation of the Zagros Fold-Thrust-Belt, SW Iran. New details on its wall microstructure are provided. The microfacies is represented by bioclastic wacke-/pack-/grainstones with ...

2014
T. C. Moore Bridget S. Wade Thomas Westerhold Andrea M. Erhardt Helen K. Coxall Jack Baldauf Meghan Wagner

There is general agreement that productivity in high latitudes increased in the late Eocene and remained high in the early Oligocene. Evidence for both increased and decreased productivity across the Eocene-Oligocene transition (EOT) in the tropics has been presented, usually based on only one paleoproductivity proxy and often in sites with incomplete recovery of the EOT itself. A complete reco...

2011
Felix Schlagintweit

Some new and poorly known larger benthic foraminifera are described from Middle Jurassic (Upper Aalenian–Bajocian) shallow-water limestones of the Croatian Karst Dinarides. Cymbriaella lorigae FUGAGNOLI is reported for the fi rst time outside its type-locality, the Upper Pliensbachian of the Southern Alps. New taxa described include Bosniella bassoulleti n. sp. and Dubrovnikella septfontainei n...

2009
CARL WUNSCH

Difficulties remain with theoretical explanations of the apparent reduced zonal sea surface temperature gradient in the tropical Pacific of the Pliocene. One favored hypothesis is that it was a ‘‘permanent El Niño’’ state, with the warm phase of ENSO remaining fixed over millions of years. Here, an alternative is suggested— that there was a ‘‘perpetually running ENSO’’ with a shorter return tim...

Journal: Geopersia 2016

Study of a late Late Santonian to Late Campanian hemipelagic succession from Abtalkh Formation at the Bahadorkhan section (Central Kopet-Dagh) enabled us to verify paleoecology changes based on planktonic and benthic foraminifera assemblage. Bahadorkhan section is consisted of calcareous shale, lime marl, marl, and a few dispersed chalky limestone beds. Upper and lower boundaries of Abtalkh For...

Journal: :رخساره های رسوبی 0
رضوان دهقان امرالله صفری

the qom formation in ghohrud area, have been investigated in order to determine its biostratigraphy and palaeoecology. the thickness of qom formation is 325 meters at the study area and consists of thin, medium to thick bedded and massive limestons. they underline on eocene volcanic with disconformably and its upper boundary is overlain by alluvium. based on thin section studies 14 genera and 2...

2009
CARL WUNSCH

Difficulties remain with theoretical explanations of the apparent reduced zonal sea surface temperature gradient in the tropical Pacific of the Pliocene. One favored hypothesis is that it was a ‘‘permanent El Niño’’ state, with the warm phase of ENSO remaining fixed over millions of years. Here, an alternative is suggested— that there was a ‘‘perpetually running ENSO’’ with a shorter return tim...

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