Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 19 of 19 for “"Planktic foraminifera"”.
-
Climate proxies in planktic foraminifera: Environmental or biomineralisation controls?
The calcite shells (or ‘tests’) of foraminifera are among the best archives of Earth’s past climate. Numerous trace elements and isotopes in foraminiferal fossils have been applied as proxies to reconstruct ocean environments over geological time. However, the proxy-environment correlations often …
-
Sodium-Calcium Ratios in the Planktic Foraminifera <i>Trilobatus Sacculifer</i> as a Proxy for Sea Surface Salinity
… salinity and the incorporation of sodium into foraminiferal calcite, suggesting a potential new proxy for reconstructing past changes in sea surface salinity (SSS) (Mezger et al., 2016 and Bertlich et al., 2018). In order to test the applicability of this new proxy in an open-ocean setting, …
-
Nitrogen cycling in the subtropical southeast Atlantic and southwest Indian Oceans as recorded by the nitrogen isotopes of modern planktic foraminifera
… and the long history of using fossil foraminifera to reconstruct past ocean conditions, it is only in recent years, due to methodological advances, that the nitrogen isotope ratio (δ15N) of foraminifera has become a viable proxy for past marine nutrient cycling. Organic N trapped …
-
Abrupt climate change in the Atlantic Ocean during the last 20,000 years : insights from multi-element analysis of benthic and planktic foraminifera and coupled OA-GCM
Minor and trace element records of planktic and benthic foraminifera from Atlantic sediment cores, as well as output from a coupled OAGCM, were used to investigate the magnitude and distribution of the oceanic response to abrupt climate events of the past 20 kyr. The study addressed three major …
-
Abrupt climate change in the Atlantic Ocean during the last 20,000 years : insights from multi-element analysis of benthic and planktic foraminifera and a coupled OA-GCM
Minor and trace element records from planktic and benthic foraminifera from Atlantic sediment cores, as well as outputfrom a coupled OA·GCM, were used to investigate the magnitude and distribution of the oceanic response to abrupt Climate events.of the past 20,000 years. The study addressed three …
-
FORAMINIFERAL DISTRIBUTION AND SEQUENCE STRATIGRAPHY OF OXFORDIAN SUCCESSIONS IN THE WESSEX/ANGLO-PARIS BASIN
… South Dorset and Normandy were obtained, and foraminifera extracted. Examination of the fauna revealed representatives from 23 families, comprising 36 genera and 126 species. All species were identified and the taxonomy of each studied and described. The abundance and distribution patterns of …
-
Response of pteropod and related faunas to climate change and ocean acidification
… Sea and Indian Ocean. Pteropods, heteropods and planktic foraminifera were picked from samples to provide palaeoenvironmental data for each core. Determination of pteropod calcification was made using the Limacina Dissolution Index (LDX) and the average shell size of Limacina inflata specimens. …
-
Reconstructing Surface Water Carbonate Ion Concentration Changes in the Eastern Equatorial Pacific Across Glacial Transitions
… climate changes. I measured B/Ca ratios in the planktic foraminifera Globigerina bulloides from core MV1014-17JC (00º10.83’S, 85º52.00’W; 2846 m water depth) as a proxy for changes in surface water carbonate ion concentration ([CO<sub>3</sub><sup>2-</sup>]) in the EEP across both climate …
-
Diffraction and Spectroscopy of Marine Calcite Biominerals: Insights into Structure and Geochemistry
… produced by marine organisms. Organisms such as foraminifera and coccolithophores provide an unparalleled 'proxy’ archive of past marine conditions. The way in which these organisms record these proxy archives is largely unknown, and is a fundamental question in applying and interpreting …
-
The centennial and millennial variability of the IndoPacific warm pool and the Indonesian Throughflow
… Mg/Ca and [delta]¹⁸0 of calcite of the calcitic planktic foraminifera Globigerinoides ruber (G. ruber) were used to estimate the sea surface temperature and [delta]¹⁸0 of water, an indicator of hydrologic conditions, over the past 20,000 years. I also attempted to estimate thermocline structure …
-
Early Palaeogene planktic foraminiferal assemblages in Australasian sequences: links to past changes in climate and carbon cycling
… μm), benthic foraminifer abundance (BENTH), and planktic foraminifer fragmentation ratio (FRAG) were measured to create a record of dissolution. There are three intervals where dissolution parameters indicate prominent dissolution episodes for both holes between 65 and 33.7 Ma: during the middle …
-
Neogene to quaternary foraminifera from the western margin of southern Africa
… how the margin evolved. Fossil shells (tests) of foraminifera (singlecelled protists) from twenty cores from the Namibian shelf (199 to 309 m water depth) and three cores from the western slope (874 to 3631 m water depth) of South Africa were studied to determine the middle Miocene to Quaternary …
-
Benthic foraminiferal change and depositional history across the Cretaceous – Paleogene (K/Pg) boundary in the Brazos River area, Texas
… impact or multiple impacts. The benthic foraminiferal data generated indicates significant changes in palaeoecology of the benthic foraminifera across the K/Pg boundary. The benthic foraminifera do not experience a mass extinction, unlike the planktic foraminifera, which were …
-
Aspects of Neogene palaeoceanography in the southern Tasman Sea (DSDP site 593)
… are nannofossil ooze changing upcore to foraminifera-bearing nannofossil ooze. This change in texture has been attributed to intermittent winnowing at the site and experimentally determined to be due to selective removal of grains sized 3-13 ηm, which comprise nannofossil placoliths. The …
-
The Role of the Ocean in MIS 4 Climatic Changes and Atmospheric CO₂ Variability: a Geochemical Fingerprinting Approach
… in the future. High resolution planktonic foraminifera Mg/Ca-based SST reconstructions from the Iberian Margin during MIS 4 show that certain aspects of the surface ocean response may not always track Greenland temperature and that Greenland ice core records do not serve as a universal …
-
Characteristics and evolution of a dynamic prograding continental margin: the late Neogene Giant Foresets Formation, northern Taranaki Basin, New Zealand
… and the paleoenvironmental interpretation of foraminiferal data derived from well cuttings samples. Outbuilding of the modem continental shelf-slope margin began during the Early Miocene as the regressive phase of a 1ˢᵗ-order megacycle. Four 2ⁿᵈ-order cycles superimposed on this megacycle have …