نتایج جستجو برای: planktonic foraminifera

تعداد نتایج: 9925  

2013
Steffanie Kraft Martin Frank Ed C. Hathorne Syee Weldeab

The radiogenic neodymium (Nd) isotope composition of foraminiferal shells provides a powerful archive to investigate past changes in sources and mixing of water masses. However, seawater Nd isotope ratios extracted from foraminiferal shells can be biased by contaminant phases such as organic matter, silicates, or ferromanganese coatings, the removal of which requires rigorous multiple step clea...

2001
RICHARD K. OLSSON JAMES D. WRIGHT KENNETH G. MILLER

A latest Maastrichtian global warming event, which began approximately 450 k.y. and ended about 22 k.y. prior to the K/T boundary, is associated with the poleward migration of the warm-water planktonic foraminifer Pseudotextularia elegans. The warming event was apparently inititated by greenhouse warming due to the main outpouring of the Deccan Traps in India and is now well documented in the N...

In this research systematics and biostratigraphy of the Cretaceous deposits foraminifera in Kerch section, southwestern Qayen, in the eastern margin of the Lut Block, were studied in detail. This section with 260 meters thickness, mainly formed by gray to cream color marl and shale, marly limestone and limestone laid on a light-colored limestone bed at the base. Seventeen genera and twenty two ...

Journal: :Journal of Micropalaeontology 1998

Journal: :Journal of Micropalaeontology 1988

2015
T. Roy F. Lombard L. Bopp M. Gehlen

Planktonic Foraminifera are a major contributor to the deep carbonate flux and their microfossil deposits form one of the richest databases for reconstructing paleoenvironments, particularly through changes in their taxonomic and shell composition. Using an empirically based planktonic foraminifer model that incorporates three known major physiological drivers of their biogeography – temperatur...

The study of planktonic foraminifera in Jorband section reveals two major events in Campanian- Maastrichtian boundary and early-late Maastrichtian bio-diversification. In this study, occurrence and species richness of planktonic foraminifera in Jorband area show the warm marine environment dominant during early to late Campanian and it could be correlating by tropical and subtropical biozones. ...

2016
Erik Wolfgring Michael Wagreich

Deposits spanning the Radotruncana calcarata Taxon Range Zone at the Postalm section, Northern Calcareous Alps (Austria) are examined quantitatively for foraminiferal assemblages, especially the planktonic group. This study focuses on establishing a high resolution record spanning an 800 ka long stratigraphic interval from the active continental margin of the Penninic Ocean. The Postalm section...

2006
Bridget S. Wade William A. Berggren Richard K. Olsson

Planktonic foraminifera from a continuous Oligocene succession with clear magnetochronology and sediment cycles at Ocean Drilling Program Site 1218 (equatorial Pacific Ocean) were studied in the interval from 27 to 30 Ma. Paragloborotalia taxa are common and we examined their size, relative abundance, and stable isotopes. Multispecies stable isotope data indicate the depth habitats of Oligocene...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Jocelyn Anne Sessa Ekaterina Larina Katja Knoll Matthew Garb J Kirk Cochran Brian T Huber Kenneth G MacLeod Neil H Landman

Ammonites are among the best-known fossils of the Phanerozoic, yet their habitat is poorly understood. Three common ammonite families (Baculitidae, Scaphitidae, and Sphenodiscidae) co-occur with well-preserved planktonic and benthic organisms at the type locality of the upper Maastrichtian Owl Creek Formation, offering an excellent opportunity to constrain their depth habitats through isotopic ...

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