نتایج جستجو برای: benthic foraminifera
تعداد نتایج: 15528 فیلتر نتایج به سال:
To assess the influence of orbital-scale variations on late Oligocene to early Miocene climate and ocean chemistry, high-resolution (~5 kyr) benthic foraminiferal carbon and oxygen isotope and percent coarse fraction time series were constructed for Ocean Drilling Program site 929 on Ceara Rise in the western equatorial Atlantic. These time series exhibit pervasive lowto high-frequency variabil...
The marine ecosystem has been severely disturbed by several transient paleoenvironmental events (<200 kyr duration) during the early Paleogene, of which the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) was the most prominent. Over the last decade a number of similar events of Paleocene and Eocene age have been discovered. However, relatively little attention has been paid to pre-PETM events,...
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...
Planktic foraminifera have traditionally been classified within a single order: Globigerinida. However, recent phylogenetic studies, both molecular and stratophenetic, are evidencing the polyphyletic origin of planktic from several benthic ancestors. At least four independent events benthic-planktic transition identified. One them occurred after Cretaceous–Paleogene boundary mass extincti...
Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs) where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with (13)C and (15)N) by calcareous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern ...
Purpose. The work studies Sinjar formation (upper Paleocene lower Eocene) within the Bazyan anticline in Sulaimaniyah region (northeastern Iraq). facies analysis is based on petrographic study of limestone deposits and essential to identify their nature. sediments that formed have a high content skeletal granules which include small amount red algae residues unicellular organisms-foraminifera. ...
C. Borrelli, A. Sabbatini, G. M. Luna, C. Morigi, R. Danovaro, and A. Negri Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Science Center Jonsson-Rowland, 1W19, 110 8th Street, Troy, NY, 12180, USA Department of Marine Science, Polytechnic University of Marche, Via Brecce Bianche, 60122 Ancona, Italy Stratigraphy Department, Geological Survey of Denmark and Gr...
The sulfur content of planktonic and benthic foraminifera was measured in specimens recovered from deep-sea sediment cores and individuals grown in culture. A new method for measuring sulfur in foraminiferal calcium carbonate was developed, employing a high-resolution inductively coupled plasma-mass spectrometer. The sulfur measurements, expressed as sulfur-to-calcium (S/Ca) ratios in the foram...
Large benthic foraminifera (LBF) are important for reef sediment formation, but sensitive to elevated temperature and nutrients. However, it is possible that conspecific foraminifera living in different reef sites present divergent response to environmental shifts. We investigated how populations of Amphistegina lobifera from reef sites located along a temperature and nutrient gradient of the n...
Benthic foraminifera are significant indicators of habitat changes and useful for paleoenvironmental reconstruction. During the Permian period, variation in species, individual sizes, morphological characteristics different assemblages, such as fusulinids, is a clue to paleoecological interpretations. The eastern part Sichuan Basin, located near equator middle Permian, Guadalupian was precipita...
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