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1
Reichelt, Kerstin. "Late Aptian-Albian of the Vocontian Basin (SE-France) and Albian of NE-Texas biostratigraphic and paleoceanographic implications by planktic foraminifera faunas /." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974321591.
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Heuser, Alexander. "Variations of calcium isotopes (d44Ca) [delta 44 Ca] in foraminifers over the past 24 Ma." [S.l.] : [s.n.], 2002. http://e-diss.uni-kiel.de/diss_713/d713.pdf.
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Rückheim, Sylvia. "The onset of planktic foraminifera in the mid-Cretaceous of the Boreal Realm." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975763350.
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Buchan, Olivia Claire Lewis Ronald D. "Relationships between large benthic foraminifera and their seagrass habitats, San Salvador, Bahamas." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/BUCHAN_OLIVIA_31.pdf.
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Young, Melinda. "The foraminiferal and sedimentological dynamics of a Portuguese submarine canyon system." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295866.
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Ferdinando, Darren. "Ostracode and foraminiferal taxonomy and palaeoecology of the Fossil Cliff Member of the Holmwood Shale, northern Perth Basin, Western Australia." University of Western Australia. Dept. of Geology and Geophysics, 2001. http://theses.library.uwa.edu.au/adt-WU2003.0019.
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The Sakmarian (Cisuralian, Permian) Fossil Cliff Member of the Holmwood Shale is situated in the northern Perth Basin, Western Australia, and consists of alternating beds of shale and silty calcarenite forming three parasequences. Within this member a diverse fauna of ostracodes and foraminifera are present. During the Cisuralian the northern Perth Basin formed part of the Gondwanan supercontinent and was linked to Greater India via an epeiric sea that opened to the north. The ostracode fauna is restricted to the calcareous beds of the member and consists of a diverse benthic fauna comprising 31 new species and 13 previously recorded species. Species from the Healdioidea, Bairdioidea, Youngielloidea, and Thlipsuroidea dominate the assemblage and suggest a normal-marine environment during the period represented by the calcareous beds, with an overall shallowing trend up the sequence. The fauna shows some similarity to faunas from the Tethyan deposits of North America and the Boreal deposits of Russia during the Late Carboniferous and Cisuralian. Twenty-eight species of foraminifera were recorded from the Fossil Cliff Member and underlying Holmwood Shale and comprise two distinct faunas, an agglutinated benthic foraminiferal fauna found within the shale beds and a calcareous benthic foraminiferal fauna present in the calcarenite units. The agglutinated foraminifera are inferred to represent deposition in dysoxic to suboxic (0.1-1.5 mL/LO2;), poorly circulated bottom waters below wave base. The calcareous foraminifera are inferred to represent deposition in normal-marine conditions. Both foraminiferal assemblages show a shallowing trend in their distribution that matches the trend identified in the ostracode fauna. Based upon the palaeoecology of the ostracode and foraminiferal faunas, the depositional environment for the Fossil Cliff Member is inferred to have been within shallow water in an epeiric basin during an overall marine regression that is overprinted by eustatic and isostatic oscillations resulting from deglaciation that occurred during the early Sakmarian (Cisuralian). These sea-level oscillations raised and lowered the oxic surface waters of the epeiric sea above and below the substrate resulting in a sparse agglutinated foraminiferal fauna or an abundant and diverse ostracode and calcareous foraminiferal fauna respectively.
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Stewart, Iain A. "The molecular evolution of planktic foraminifera and its implications for the fossil record." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/13020.
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The marine microfossils of planktic foraminifers are widely used for investigating palaeoceanographic and palaeoclimatic conditions. The objective of this project was to investigate genotypic variation within planktic foraminiferal morphospecies and the spatial distribution of genotypes in the subpolar, transitional and subtropical North Atlantic. Foraminiferal genomic DNA was extracted and the ~1000 base pair 3' terminal region of the small subunit ribosomal RNA gene was amplified using the polymerase chain reaction. Using distance-based molecular phylogenetic analysis, a neighbour-joining phylogeny was reconstructed based on 31 planktic and15 benthic previously sequenced foraminifera and extended to include 15 genotype sequences obtained from the North Atlantic during this study. Bulk plankton samples were collected for preliminary examination of genotype/morphotype relationships. The molecular phylogeny is largely consistent with the foraminiferal fossil record. It supports the suggestion that the origins of planktic foraminifers are polyphyletic, as the spinose planktic foraminifers cluster separately from the non-spinose planktic foraminifers within the phylogeny. Brachn length variation within the planktic cluster reflects large differences in evolution rate between morphospecies. Within the North Atlantic, genotypic variation has been identified within the morphospecies, Globigerina bulloides, Turborotalita quinqueloba, Globigerinella siphonifera, Globigerinella calida, Globigerinoides ruber and Neogloboquadrina pachyderma. The distribution of genotypes is complex, and it has been found that genotypes, representing a single morphospecies, often co-exist within the water column. This could be indicative of cryptic speciation, suggesting that North Atlantic planktic foraminiferal diversity is much higher than fossil record interpretations have indicated. The genotypes within G. bulloides, G. siphonifera, G. calida and T. quinqueloba have different geographic distributions within the North Atlantic. It is apparent that G. bulloides Types IIa and IIb and G. siphonifera Types IIa and IIb have extensive distributions suggesting that they are more generalist in adaptation, and tolerant to a wide range of oceanic conditions.
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Brombacher, Jenneke Fopke Antonia. "High-resolution evolution : calibration and application of fossil foraminifera in evolutionary time series." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/416830/.
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Many evolutionary processes are well-studied on generational and macroevolutionary time scales, but much less is known about the processes bridging short- and long-term biotic change. This is commonly due to a lack of sufficiently-high-resolution fossil records over long microevolutionary time scales. The work presented in this thesis describes new calibrations and applications of planktonic foraminifera in evolutionary biology. The high-resolution fossil archives of planktonic foraminifera enable construction of continuous, long-term microevolutionary time series of large numbers (>10,000) of individuals. In Chapter 2 I study the repeatability of traits commonly used in studies describing foraminifera evolution. The results show that some traits are reliable, whereas others are very susceptible to small mounting-induced errors and should be used with caution. Chapter 3 deals with various representations of foraminifera body size, and whether these proxies remain accurate in a lineage undergoing morphological change. This was shown to be the case for foraminifera shell area as measured from a two-dimensional image, but less so for shell diameter. In Chapter 4 I study within- and among-population allometries during an interval of global climatic upheaval. When climate remains constant the within-population allometries predict evolutionary change from one time-step to the next. However, the evolutionary allometry measured across step-wise environmental change deviates significantly from the static evolutionary allometries. Changes in biodiversity are often linked to climate change, usually represented by global temperature. However, climate consists of many interacting variables, and species likely respond to the entire climate system as opposed to individual variables. In Chapter 5 I show that evolutionary response in two species of planktonic foraminifera is indeed best explained by combinations of environmental parameters. Chapter 6 presents evolutionary time series of two species of planktonic foraminifera from six sites along an Atlantic transect over 600,000 years. The results show that temporal dynamics do not match spatial variation, implying that care should be taken when extrapolating one population’s predicted response to another location.
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Burbidge, Susan M. (Susan Margot) Carleton University Dissertation Geology. "Late quaternary benthic foraminifera of the Patton-Murray Seamount group, Gulf of Alaska." Ottawa, 1992.
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Abke, Rodney Alan. "A fossil assemblage of ostracoda, foraminifera, and gastropoda of the West Texas salt flats." Virtual Press, 1994. http://liblink.bsu.edu/uhtbin/catkey/897497.
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The salt flats of west Texas are large ephemeral lakes, Pleistocene to Holocene in age. The evaporite material in these lakes represents the sedimentary history of the lake and the surrounding area. Recently, a fossil assemblage was found in the sediments of this deposit. This assemblage includes four species of ostracoda (Limnocvthere staplini, Candona rawsoni, Candona thomasi, and Cvprideis salbrosa), two species of gastropoda, (Amnicola decepta, and Amnicola pilsbrvi), and discovery is significant because this assemblage has not been previously reported, and it provides an opportunity to reconstruct part of the physical and chemical environment of the salt flats during a portion of its history. Autecological comparison of these species indicate that they lived in a shallow, alkaline, brackish water environment. The known paleoclimate of the area, and the sedimentology support this interpretation.Department of Geology
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Stritch, Rebecca A. (Rebecca Ann) Carleton University Dissertation Earth Sciences. "Early Cretaceous (Albian) foraminifera in Northwestern and Central Alberta, Canada; biostratigraphy and paleoenvironmental changes." Ottawa, 1997.
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Halldén, Tom. "Förändringar i västra Yoldiahavets vattenmiljö under trettioett år : En studie av fossil från ostracoder, mollusker och foraminiferer från Myssjaren, östra Mellansverige." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92993.
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I denna studie undersöks hur vattenmiljön förändrades i ett område av västra Yoldiahavet, idag sjön Myssjaren i östra Mellansverige. Syftet med undersökningen har varit att återskapa hur vattnets salthalt förändrades i området genom att studera förekomsten av fossil från saltvattenkrävande bentisk kalkskalsfauna i lera från perioden. Fossil hittades från sju år, 10 395-10 388 lervarvsår BP, av den 31 år långa period, 10 410-10 379 lervarvsår BP, som har undersökts. Utifrån fossilförekomsten kunde det konstateras att vattnet var bräckt under dessa sju år. Eftersom att fossil inte hittades från tidigare och senare perioder Därför är det möjligt att vattnet var bräckt både före och efter denna period. Det som begränsade de undersökta arternas utbredning i området var halten suspenderat sediment i vattnet. Det var en konsekvens av att mycket sediment transporterades till området i och med att området befann sig mellan två större utlopp av glacialt smältvatten. Därför har denna studie, förutom att konstatera att vattnet var bräckt under den undersökta perioden, även visat en succession av arter i Yoldiahavet. I studien identifieras också en 4 år lång kallperiod som varade mellan 10 393-10 389 lervarvsår BP. Vid 10 387 lervarvsår BP börjar iskanten att avancera, troligen som ett resultat av denna kallperiod, vilket slutligen leder till att de undersökta arterna upphör att förekomma i leran.
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Campbell, Robert John. "Calcareous nannofossil and foraminiferal analysis of the middle to upper cretaceous Bathurst Island Group, Northern Bonaparte Basin and Darwin Shelf, Northern Australia." University of Western Australia. School of Earth and Geographical Sciences, 2003. http://theses.library.uwa.edu.au/adt-WU2003.0025.
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[Truncated abstract] The Northern Bonaparte Basin and adjacent Darwin Shelf form part of a major petroleum province on the northwestern margin of Australia. The middle to Late Cretaceous Bathurst Island Group consists of siliciclastic and pelagic carbonate strata that form the regional seal to underlying Upper Jurassic and Lower Cretaceous reservoir sandstones. The Bathurst Island Group has previously been subdivided into four stratigraphic sequences or ‘play intervals’ bound by regional disconformities in the Valanginian (KV horizon), Lower Aptian (KA horizon), upper Lower Cenomanian (KC horizon), Middle Campanian (KSC horizon), and at the CretaceousPaleocene boundary (T horizon). Correlation of these sedimentary packages and stratigraphic surfaces requires high-resolution calcareous microfossil biostratigraphy, while palaeobathymetric determinations based on benthonic foraminiferal assemblages are important for determining the subsidence history of the area and relative sea-level changes. This study presents the first detailed stratigraphic distributions, taxonomic lists and illustrations of foraminifera and calcareous nannofossils from the Bathurst Island Group of the Northern Bonaparte Basin and Darwin Shelf. A biostratigraphic framework has been constructed for the study area incorporating ‘standard’ (Tethyan) Cretaceous planktonic foraminiferal and calcareous nannofossil events where applicable, and integrating locally defined events where necessary. This framework allows Cretaceous strata to be correlated regionally across the study area and to the global chronostratigraphic scale. Correlation of the Northern Bonaparte Basin and Darwin Shelf strata to the Cretaceous Stages and international time scale is based on recent ties of nannofossil and foraminiferal events to macrofossil zones and palaeomagnetic polarity chrons at ratified and proposed Global Stratotype Sections and Points (GSSPs). Calcareous nannofossil events recorded in the study area that are critical for defining stage boundaries include the lowest occurrences of Prediscosphaera columnata, Micula decussata, Lithastrinus grillii, and Aspidolithus parcus parcus, and the highest occurrences of Helenea chiastia, Lithastrinus moratus, Aspidolithus parcus constrictus, and Eiffellithus eximius. Important planktonic foraminiferal events for correlation include the lowest occurrences of Rotalipora gr. globotruncanoides, and Dicarinella asymetrica, and the highest occurrences of Planomalina buxtorfi, Rotalipora cushmani, and Dicarinella asymetrica. During the middle to Late Cretaceous the Northern Bonaparte Basin and Darwin Shelf occupied mid-high palaeolatitudes between 35ºS to 45ºS. These palaeolatitudes are reflected in the transitional character of the planktonic microfossil assemblages, which combine elements of the low-latitude, warm-water Tethyan Province to the north and the cool-water high-latitude Austral Province to the south. ‘Standard’ Tethyan zonations are most applicable for uppermost AlbianMiddle Campanian strata because equator-to-pole temperature gradients were weakly developed, and global climate was warm and equable during this interval. These conditions resulted in broad latitudinal distributions for Tethyan marker species, and consequently most UC calcareous nannofossil zones and European-Mediterranean planktonic foraminiferal zones are recognised. In contrast, the EarlyLate Albian and the late Middle CampanianMaastrichtian were intervals of greater bioprovinciality and stronger palaeotemperature gradients. In these intervals application of the Tethyan zonations is more difficult, and a number of the Tethyan biostratigraphic markers are absent from the study area (e.g. Ticinella species in the Albian and Radotruncana calcarata in the Late Campanian). Cretaceous palaeobathymetric reconstruction of the study area is based on comparison of the foraminiferal assemblages with those of previous Cretaceous palaeobathymetric studies. Marginal marine assemblages consist solely of low diversity siliceous agglutinated foraminifera (e.g. Trochammina). Inner and middle neritic water depths (0-100 m) contain rare to common planktonic foraminifera (mainly globigerine forms), robertinids (e.g. Epistomina), siliceous agglutinates, lagenids, buliminids (e.g. Neobulimina), and rotaliids. The outer neritic zone (100-200 m water depth) contains abundant planktonic foraminifera (keeled and globigerine), calcareous agglutinates (e.g. Dorothia), and diverse lagenids, buliminids, and rotaliids. Upper-middle bathyal water depths (200-1000 m) are characterised by abundant planktonic foraminifera, common siliceous agglutinated taxa (e.g. Glomospira), rare to common Osangularia, and globular species of Gyroidinoides, Pullenia, and Paralabamina.
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Goineau, Aurélie. "ECOLOGIE DES FORAMINIFERES BENTHIQUES DANS LE PRODELTA DU RHONE DETERMINATION DE BIO-INDICATEURS ENVIRONNEMENTAUX ET RECONSTITUTION HISTORIQUE D'UNE ANTHROPISATION RECENTE." Phd thesis, Université d'Angers, 2011. http://tel.archives-ouvertes.fr/tel-00660713.
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Cette thèse a été réalisée dans le cadre de 2 projets ANR (Vulnérabilité : Milieux et Climats) : le projet CHACCRA (Climate and Human-induced Alterations in Carbon Cycling at the River-seA connection) et le projet EXTREMA (Episodes météo-climatiques extrêmes et redistribution des masses sédimentaires et des polluants associés au sein d'un système côtier). L'objectif de ce travail doctoral a été de définir les caractéristiques écologiques des faunes de foraminifères benthiques vivant sur la plate-forme continentale dans la zone d'influence du Rhône (Golfe du Lion, Nord-ouest de la Mer Méditerranée), afin d'utiliser les faunes benthiques en tant que bioindicateurs des caractéristiques environnementales actuelles et passées. Aussi, les facteurs environnementaux contraignant la structure (densité, composition faunistique) ainsi que la distribution spatiale et la variabilité temporelle des faunes actuelles de foraminifères benthiques ont été identifiés. Il a été mis en évidence Ie rôle des apports épisodiques de sédiments lors des crues du Rhône, constituant un facteur de stress pour les faunes benthiques vivant près de l'embouchure. La nature et la quantité de matière organique détritique ainsi que les processus liés à la dégradation de cette matière sont également apparus comme des contraintes écologiques majeures contrôlant la dynamique spatiale et temporelle des communautés. Par la suite, un outil basé sur les assemblages fossiles de foraminifères benthiques préservés dans les sédiments au débouché du fleuve a été défini. Celui-ci a permis de retracer l'histoire récente (400 dernières années) du prodelta du Rhône en termes d'apports fluviatiles terrigènes et organiques.
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Waite, Amanda J. "Top down and bottom up a comparison of nannofossil strontium/calcium and benthic foraminiferal accumulation rates as paleoproductivity indicators /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 3.19 Mb., 95p, 2005. http://wwwlib.umi.com/dissertations/fullcit/1428257.
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Gaillot, Jérémie. "The late Permian-early Triassic Khuff formation in the Middle-East : sequence biostratigraphy and palaeoenvironments by means of calcareous algae and foraminifers." Lille 1, 2006. http://www.theses.fr/2006LIL10162.
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Les carbonates et évaporites de la formation Khuff (Permien supérieur) de la plate-forme arabique abritent un des plus grands réservoirs de gaz au monde. Le matériel étudié comprend 6000 échantillons de subsurface ou d'affleurements et provient du Golfe persique, de Turquie, d'Arabie Seoudite et de Chine du Sud. Les objectifs de l'étude étaient de: (1) construire un cadre biostratigraphique robuste à partir de l'étude systématique détaillée des algues calcaires et des foraminifères, (2) caractériser les environnements de dépôt et leur succession dans le temps à la fin du Permien et au Trias basal. La comparaison des différents assemblages a permis de subdiviser l'intervalle étudié en 8 unités distinctes limitées par des niveaux d'importants renouvellements biotiques. A la fin du Permien, le Zagros (Iran), le Taurus (Turquie), la Chine du Sud et même le Japon partagent un assemblage de foraminifères similaire et constituaient des provinces paléogéographiques périodiquement interconnectées. L'étude paléoécologique montre que les points hauts relatifs contrôlés structuralement ont été successivement ennoyés et que le système a évolué depuis une plate-forme barrée vers une rampe très faiblement inclinée. Les unités oolithiques majeures (réservoirs) se sont développées à la fin du Wuchiapingian (partie supérieure du réservoir k4) et au début du Trias (réservoir k2), et sont piégées à l'intérieur de zones plus fortement subsidentes. La subsidence thermique liée à l'ouverture de l'Océan Neotethys est sans doute le facteur majeur contrôlant la sédimentation sur la plate-forme arabique et a joué un rôle important durant les phases successives d'extinction de la fin du PermienThe carbonates and evaporites of the late Permian Khuff formation form widespread reservoirs across the Arabian plate and concentrate the biggest gas resources in the world. The material studied includes 6000 samples from subsurface and outcrops in the Persian gulf, Turkey, Saudi Arabia and South China. The objectives of the study were (1) to build a robust biostratigraphic framework based on a detailed description of algal-foraminiferal biotic content, (2) to characterize the depositional environments and their temporal successions during the late Permian and early Triassic. By comparison of fossils distribution, the middle/late Permian Khuff deposits are divided into 8 units limited at their tops by turnovers levels, corresponding to significant reshapings of biotic assemblages. During the late Permian, Zagros (Iran), Taurus (Turkey), South China and even Japan share similar foraminiferal assemblages and represent intermittently connected palaeobiogeographic provinces. Palaeoecological results show that the structurally controlled palaeohighs are successively drowned and that the system evolves progressively from a rimmed platform towards an almost uniformly flat ramp. The major oolitic units (reservoirs) developed within high-subsiding areas by sediment volume funneling, mainly during the late Wuchiapingian (upper k4 reservoir) and early Triassic (k2 reservoir). The thermal subsidence during the Neotethyan spreading is likely the main factor that drove the Khuff deposition on the Arabian platform and can be related to the demise of the regional Permian fauna
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Dessandier, Pierre-Antoine. "Distribution des faunes vivantes, mortes et fossiles de foraminifères benthiques sur la marge portugaise : impact des apports fluviatiles et de la qualité de la matière organique." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0351/document.
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La marge ibérique est un milieu biologiquement productif régit par l'influence d'un upwelling saisonnier et des apports continentaux. Les foraminifères benthiques sont des protistes matins qui présentent une grande sensibilité aux conditions environnementales. Ils apparaissent ainsi comme des bio-indicateurs particulièrement efficaces dans ce type de contexte. Dans le cadre de cette thèse, les faunes de foraminifères benthiques, vivants, morts et fossiles prélevées sur un total de 23 carottes interfaces et deux carottes et deux carottes piston, essentiellement situées au débouché de quatre feluves ouest-ibériques majeurs (Douro, Mondego, Tage et Sado) ont été étudiés.Cette analyse faunistique, conjointe à des mesures sédimentaires et géochimiques a permis d'identifier l'impact de la qualité de la matière organique, et donc des apports fluviatiles sur la distribution des faunes vivantes en période hivernale. La comparaison des faunes mortes et vivantes sur les premiers centimètres de sédiments illustre la variation saisonnière de la réponse faunistique à l'upwelling et aux apports continentaux. Elle met également en évidence l'impact des processus taphonomiques sur la conservation de ces bio-indicateurs en vue de permettre une meilleure compréhension du signal fossile de ces faunes. L'application paléoenvironnementale de ces bio-indicateurs a été menée sur une carotte longue prélevée au large du Tage qui permet une reconstruction des derniers 5700 ans cal. BP. Elle a permis de mettre en évidence des périodes caractérisées par des apports importants de matière organique issus du fleuve ainsi que des variations de l'intensité de l'upwellingThe Iberian Margin is a highly productive system driven by coastal upwelling and river inputs. Benthic foraminifera are marine protists particularly sensitive to environmental conditions. Hence they appear well suited bio-indicators for such environment. In the framework of this thesis, living, dead and fossil benthic foraminifera were analized on 23 surface sediment cores and two piston cores essentially from locations off the major rivers of the Portuguese Coast (Douro, Mondego, Tagus and Sado). This faunal analysis, combined with sedimentary and geochemical measurements allow thhe identification of the impact of fluvial exports and organic matter quality during the late winter period. The comparison of dead and living communities, on the first few centimeters of the sediment, shows the seasonal variation of faunas controlled by upwelling activity and riverine discharges intensity. The impact of taphonomical processes on the preservation of these bio-indicators is also investigated in the perspective of a better understanding ofthe fossil signal of these faunas. The paleoenvironmental application of these bio-indicators was then conducted on a 10 m long core from the Tagus shelf that allows paleoreconstruction for the last 5,700 cal. yr BP. The fossil benthic foraminifera record shows that some periods were characterized by intense river runoff and others by variable intensity of the seasonal upwelling
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Petrocchi, Francesca. "Paleo- ecologia dei Foraminiferi in ambiente estremo: un caso di studio in Antartide." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/9763/.
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Nel presente lavoro sono state analizzate le distribuzioni quantitative dei Foraminiferi planctonici e bentonici presenti in una carota e in un box core prelevati nel Mare di Ross in Antartide durante la campagna KOPRI ANTA03 nel Febbraio 2013 nell’ambito del progetto di ricerca congiunto Corea- Italia finanziato dal Progetto Nazionale di Ricerca in Antartide (PNRA). Scopo del lavoro è stato quello di comprendere l’evoluzione ambientale dell’area in base alla distribuzione quantitativa e qualitativa delle associazioni a Foraminiferi nel tardo Quaternario. In base alla distribuzione quantitativa dei Foraminiferi identificati, la sequenza sedimentaria della carota C2 è stata suddivisa in tre intervalli corrispondenti a tre principali fasi paleoceanografiche/paleoclimatiche. La prima fase, più antica di 18 ka, caratterizzata dall’assenza o rarità di forme documenta un ambiente con presenza di copertura glaciale. La seconda, depositatasi tra 18 ka e ~8 ka è caratterizzata da una maggiore variabilità intraspecifica e riflette un miglioramento delle condizioni climatiche. La terza, corrisponde ad un periodo compreso tra ~8 ka e ~2 ka. La presenza di forme agglutinanti e l’assenza di Foraminiferi a guscio calcareo suggeriscono la presenza di condizioni di dissoluzione carbonatica sul fondale in un ambiente marino libero da copertura glaciale. La documentazione di numerosi individui allo stadio giovanile di Neogloboquadrina pachyderma durante l’intervallo B ha reso possibile avanzare ipotesi riguardo la strategia di sopravvivenza di questa specie in ambiente estremo quale il ghiaccio antartico. La somiglianza morfologica tra individui giovanili di Neogloboquadrina pachyderma riscontrata durante il nostro studio nei sedimenti a livello fossile nella carota con individui giovanili della stessa specie provenienti da campioni di ghiaccio marino antartico documentati in bibliografia, ha permesso di supportare la tesi dello sviluppo di tali forme nei pori del “microghiaccio”.
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Consorti, Lorenzo. "Selected larger benthic foraminifera (LBF) from the middle and late cretaceous global community maturation cycles in two adjoining palaeobioprovinces: pyrenees and tethys." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/403772.
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En la presente tesis se discuten los resultados de un estudio arquitectural y taxonómico sobre grandes Foraminíferos bentónicos cuya presencia caracteriza los ciclos de maturación global del Cretácico Medio y Superior. La descripción de nuevos taxones, acompañadas de consideraciones sobre su estratigrafía y distribución temporal, añade datos sobre el escenario evolutivo de los grandes Foraminíferos bentónicos que caracterizan las fases antecedentes y posteriores de la extinción ocurrida durante el limite Cenomaniense-Turoniense (CTB). La presente tesis incluye cinco artículos que presentan nuevos datos o revisan los existentes desde varias localidades (España, Italia, Irán). Se presentan nuevos datos sobre la distribución de soritoideos a lo largo de todos los ambientes carbonatados del Océano del Tethys durante el máximo del ciclo de maturación del Cretácico Medio como la revisión de Praetaberina (ex Taberina bingistani) desde sur de Italia a Irán. Este trabajo de revisión y los datos de estratigrafía isotópica muestran que la distribución del nuevo género se limita al Cenomaniense superior con dos especies; una desde la plataforma Apulica y la otra de las montañas de Zagros. El artículo sobre los soritoideos de la península Ibérica ha sido importante para definir la distribución estratigráfica de este grupo en una zona poco estudiada. Nuevos datos sobre la recuperación y la evolución de las comunidades de grandes Foraminíferos bentónicos después de la extinción del Cenomaniense-Turoniense enriquece el conocimiento sobre la dinámica del ciclo de maturación global del Cretácico Superior en las paleobioprovincias del Pirineo y del Tethys. Los nuevos rotaloideos que aquí se presentan han sido datados por medio de la estratigrafía de estroncio, indicando la existencia de dos comunidades que evolucionaron de manera separada en cada una de las bioprovincias. Sus diversificación empiezó en el Turoniense superior pero la exacta relación temporal entre ambas áreas queda sin resolver. Finalmente, la presencia de Pseudorhapydionina en el Santoniense de la paleobioprovincia del Pirineo indica que este género sobrevivió a la extinción del CTB. Hasta ahora Pseudorhapydionina habia sido considerada típica del Cenomaniense del Tethys, pero este hallazgo indica que su evolución continuó en el Pirineo después de la extinción del CTB.Architectural and taxonomic study of selected larger benthic Foraminifera from the Upper Cretaceous of the Tethyan and Pyrenean paleobioprovinces is presented within a context of Middle and Late Cretaceous Global Community Maturation Cycles. Descriptions and determinations of the stratigraphic distributions of some new and revised taxa provide further data in reconstructing evolutionary trends among the larger benthic Foraminifera before and after the Cenomanian-Turonian boundary (CTB) extinction. This thesis includes five research papers presenting new data and reviewing existing knowledge from widespread localities (Spain, Italy and Iran). New perspectives are presented on soritoidean palaeobiogeography throughout the carbonate shelves and platforms of Tethyan Ocean during the peak of the Middle Cretaeous GCMC as well as a revision of Praetaberina (ex "Taberina" bingistani) from Southern Italy and Iran. The revision of Praetaberina and chemostratigraphy of the host strata show that the distribution of this genus is limited to the Upper Cenomanian where two species are described from the Apulian Platform and Zagros Mountains respectively. The report of Iberian soritoideans has been crucial in defining their stratigraphic distribution in a area that has been little studied. New data defining the recovery and the evolution of the foraminiferal communities after the Cenomanian-Turonian boundary extinction has enriched knowledge of the Late Cretaceous GCMC of the Pyrenean and Tethyan paleobioprovinces. The new rotaloideans described from these areas have been stratigraphically anchored by means of Strontium Isotope Stratigraphy indicating that two communities evolved separately in each palaeobioprovince. Diversification of these communities started at least during the late Turonian, but the exact timing remains unresolved. Finally the occurrence of the genus Pseudorhapydionina in the Santonian of the Pyerenean palaeobioprovince indicates that this genus was not affected by the Cenomanian-Turonian extinction event. Pseudorhapydionina was formerly considered to be confined to the Cenomanian within the Tethyan area but the new record presented here indicates its evolution in the Pyrenean area continued after the Cenonian-Turonian boundary event.
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Morard, Raphaël. "Pour une meilleure caractérisation du registre fossile pélagique : diversité morphologique, biogéographie et écologie des espèces cryptiques de foraminifères planctoniques." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00708217.
Full textAbstract:
L'utilisation des coquilles carbonatées de foraminifères planctoniques comme marqueurs paléocéanographiques repose sur l'hypothèse fondamentale que chaque espèce morphologique correspond à une espèce biologique caractéristique d'un habitat spécifique. Cette relation empirique a été récemment remise en cause par des analyses moléculaires qui ont révélé la présence systématique de plusieurs espèces génétiques (espèces cryptiques) au sein des morpho-espèces actuelles. Il a été suggéré que ces espèces cryptiques ou génotypes, présentaient (1) des préférences biogéographiques et écologiques restreintes par rapport à leur morpho-espèce respective et (2) des différences morphologiques. Dans ce travail, nous avons caractérisé la diversité génétique, morphologique et écologique de 4 morpho-espèces clefs de la paléocéanographie, i.e. Orbulina universa, Truncorotalia truncatulinoides, Globoconella inflata et Globigerina bulloides. Cette étude repose sur le développement d'un protocole d'extraction ADN non destructif pour la coquille calcaire, permettant l'analyse conjointe de la variabilité génétique et morphologique d'un même individu. Les variations de forme ou de porosité de chacun des génotypes des morphoespèces ont été quantifiées. Il apparaît que le fort degré de plasticité morphologique largement documenté chez les foraminifères planctonique et jusqu'alors interprété comme écophénotypique, est au moins en partie la conséquence du regroupement de plusieurs génotypes présentant des morphologies et préférences écologique particulières. Sur la base de ces observations, des modèles de reconnaissance morphologique permettant d'identifier les génotypes à partir de la morphologie de la coquille, utilisables à l'échelle populationnelle, ont été développés. Afin de quantifier l'impact de l'intégration de la diversité cryptique dans les reconstitutions paléocéanographiques basées sur les assemblages de foraminifères planctoniques, les fonctions de transfert couramment utilisées ont été re-calibrées en intégrant les distributions restreintes des génotypes d'O. universa, T. truncatulinoides, G. inflata et G. bulloides. Ces re-calibrations conduisent à un degré de précision jusqu'alors jamais atteint dans les reconstructions paléocéanographiques basées sur les assemblages de foraminifères planctoniques.
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Roosmawati, Nova. "Long-Term Surface Uplift History of the Active Banda Arc-Continent Collision: Depth and Age Analysis of Foraminifera from Rote and Savu Islands, Indonesia." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd887.pdf.
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Haarmann, Tim [Verfasser], Torsten [Akademischer Betreuer] Bickert, Gerold [Akademischer Betreuer] Wefer, and Geert-Jan [Akademischer Betreuer] Brummer. "The use of single foraminiferal shells for recording seasonal temperatures and water column stratification and its applicability to the fossil record / Tim Haarmann. Gutachter: Gerold Wefer ; Geert-Jan Brummer. Betreuer: Torsten Bickert." Bremen : Staats- und Universitätsbibliothek Bremen, 2012. http://d-nb.info/1072046679/34.
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Shaw, Neil B. "Biostratigraphy of the Cowlitz Formation in the upper Nehalem River Basin, northwest Oregon." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3654.
Full textAbstract:
Examination of stream and roadcut exposures of the Cowlitz Formation allows the selection of measured representative sections, and collection of fossils, from an area roughly defined by the intersection of the boundaries of Clatsop, Columbia, Tillamook and Washington counties in Oregon. The study defines the features of the local environment of deposition, correlates sections to derive a composite columnar section, and develops a checklist of species for both microfossils and megafossils of the Cowlitz Formation.
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Tiedemann, Nicholas S. "The sequence stratigraphy of the Commanchean-Gulfian interval, Big Bend National Park, West Texas." CardinalScholar 1.0, 2010. http://liblink.bsu.edu/uhtbin/catkey/1569029.
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Within Big Bend National Park, the unconformable contact between the Buda Limestone and the overlying Boquillas Formation represents the Commanchean-Gulfian boundary. Previous studies of the geochronology of this interval have relied primarily on provincial ammonite faunas rather than foraminifera, and place the Buda and basal Boquillas in the Lower Cenomanian. Because of its indurated nature, a comprehensive foraminiferal biozonation has not been acquired for the Buda Limestone. Recent revisions to Cretaceous foraminiferal biozonations and taxonomies necessitates a new biostratigraphic study of the Buda - Boquillas interval. The overlapping ranges of F. washitensis, G. bentonensis, G. caseyi, P. appenninica, P. delrioensis, P. stephani, and R. montsalvensis place the Buda within the upper portion of the Early to Middle Cenomanian Th. globotruncanoides Zone. Microkarst found on the surface of the Buda Limestone has been interpreted as representing a subaerial exposure and sequence boundary. However, microkarst-like features can result from subaqueous or intrastratal processes. Carbon and oxygen stable isotope analysis of the lower and middle Buda has indicated a mean δ13C value of 1.73‰ VPDB, which is in line with other values reported from the Lower Cenomanian. The top 2.6m of Buda contains a 0.62‰ negative δ13C shift from 1.88‰ VPDB to 1.26‰ VDPB in a 40 cm interval, expected if subaerial exposure occurred. Higher variation in measured carbon isotope values beneath the contact also lend evidence for meteoric alteration. The standard deviation in δ13C values from the top 2.8 m of the Buda is 0.207, which is 2.16 times larger than the rest of the studied section at 0.096. The Buda contains a shallow pelagic-dominated fauna of heterohelicids (45-90%), globigerinellids (3-37%), and hedbergellids (4-22%). Intermediate-depth globigerinellids display an initial increase followed by a marked decrease in abundance upsection, interpreted as sea level transgression and regression, respectively. The lower contact of the Buda with the Del Rio Clay has been previously interpreted as a subaerial exposure, and a P:B break from ~0% planktonics in the upper Del Rio to ~80% in the Buda supports this claim. This study therefore interprets both the upper and lower contacts of the Buda as
sequence boundaries. The overlying 1.2 m Boquillas is nearly devoid of benthics and represents a deeper assemblage including the double-keeled Dicarinella sp., as well as several Upper Cenomanian (D. algeriana Subzone) species. Based on foraminiferal data, the duration of the Buda - Boquillas unconformity is roughly equivalent to the missing Th. reicheli and Th. greenhornensis Biozones, or a sizable portion of the Middle Cenomanian.Systematic paleontology -- Biostratigraphy of the Buda Limestone -- Biostratigraphy of the lowermost Boquillas Formation -- Stable isotope geochemistry.
Department of Geological Sciences
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Oudet, Claudine. "Evolution des associations de foraminifères comme bio-indicateurs des paléo-environnements : le bassin subalpin (bassin vocontien et sa marge occidentale) au Cénomanien." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01019281.
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Quatre coupes ont été étudiées dans les séries marno-calcaires de talus et de bassin profond de la "fosse vocontienne" au Cénomanien. Le travail effectué à partir de plus de 800 échantillons dans lesquels les associations de foraminifères planctoniques et benthiques ont été étudiées a montré des particularités biostratigraphiques, et paléogéographiques. En effet, il existe un diachronisme dans l'extension verticale de Thalmanninella reicheli et dans l'apparition du marqueur de la base du Cénomanien supérieur (Rotalipora cushmani). T. reicheli a une extension verticale courte, mais située dans le Cénomanien inférieur peu élevé d'après les faunes d' ammonites associées; R. cushmaniapparait avant les ammonites marquant le Cénomanien moyen (Acanthoceras). Les chutes du niveau marin relatif enregistrées par des discontinuités lithologiques dans la coupe de la marge du talus au Cénomanien basal, dans la partie moyenne du Cénomanien, et au passage Cénomanien-Turonien sont également repérées par la dominance des assemblages de foraminifères benthiques opportunistes, d'abord dans les coupes de marge et de plate-forme méridionale, ensuite dans les coupes de bassin profond. Ces passages correspondent aussi à des évènements dysoxiques, liés à l'anomalie du δ13C. L'évolution des foraminifères benthiques s'avère très sensible à profondeur de l'eau et à la dysoxie,leur réponse étant plus rapide que la variation du δ13C. La régression forcée au passage Cénomanien-Turonien correspond à des dépôts de black shales dans la coupe du bassin le plus profond, traduisant l'événement anoxique OAE2. La fin de l' extension de Rotalipora cushmani, définit le sommet de l'étage dans les 4 coupes.
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Alhussein, Mohamad. "Taxonomie und Palökologie der benthischen Foraminiferen aus dem Mitteljura des Kachchh-Beckens, westliches Indien." Doctoral thesis, 2010. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-49273.
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In der vorliegenden Arbeit werden die Foraminiferenfaunen von 125 Proben, die aus drei Profilen des marinen Mitteljura (Bajocium bis Unteroxfordium) von Kachchh, West-Indien stammen, analysiert: Das Badi Nala-Jhura Village-Profil (ca. 550 m Mächtigkeit) und das Kamaguna-Profil (ca. 365 m Mächtigkeit) wurden am Jhura Hill (23°26’8’’ N; 69°37’00’’ E) ca. 17 km NW von Bhuj aufgenommen, während das dritte Profil durch den Jumara Dome (ca. 365 m Mächtigkeit) (23°40’40’’ N; 69°04’00’’ E) ca. 50 km NW des Jhura Hill liegt. Die Proben wurden lithologisch sowie nach ihren Foraminiferen-Vergesellschaftungen ausgewertet, welche wichtige Daten zur Palökologie lieferten. Die Profile umfassen die mitteljurassische Sedimentabfolge, die der Jhurio-, Patcham- und Chari-Formation des Jhura Dome und Jumara Dome angehört. Die Schichtenfolge des Bajocium und Bathonium besteht aus Karbonaten und gemischt karbonatisch-siliziklastischen Sedimenten der Jhurio- und Patcham-Formation, während im Callovium die Chari-Formation siliziklastisch dominiert ist. Die sedimentäre Abfolge des Kachchh-Beckens zeigt an der Bathonium-Callovium-Grenze signifikante Veränderungen in der Lithologie, im faunistischen Inhalt und in der Faunendiversität. Die lithologischen Veränderungen von einer Karbonat-dominierten Abfolge im mittleren und oberen Bathonium zu siliziklastischen Sedimenten im Callovium gehen mit einer Abnahme der zuvor hohen Diversität einher. Der Grund für den Faunenumschwung liegt vermutlich in einer deutlichen Änderung der Umweltbedingungen von sauerstoffreich im unteren zu sauerstoffarm im oberen Profilabschnitt, was sich in einem Wechsel von einer Kalkschaler- zu einer Sandschaler-dominierten Foraminiferenfauna dokumentiert. Eine weitere Ursache für den Fazies- und Faunenumschwung liegt in einer deutlichen KlimaÄnderung, indem heiße, aride Bedingungen im Bathonium von kühleren, feuchteren Verhältnissen zu Beginn des Callovium abgelöst wurden. Taxonomisch konnten insgesamt 111 Foraminiferentaxa identifiziert werden, die 43 Gattungen angehören. Insgesamt wurden 24 Sandschaler- und 85 benthische Kalkschaler-Taxa sowie 2 Arten planktischer Foraminiferen (Globuligerina) in den untersuchten Profilen bestimmt. Die benthischen Formen dominieren somit bei weitem an Diversität und Häufigkeit, da die planktischen Protoglobigerinen im mittleren Jura global noch keine große Rolle spielten. Aufgrund der spärlich vorhandenen Literatur wurde jedes Taxon inklusive Synonymieliste beschrieben, durch rasterelektronen-mikroskopische Aufnahmen (REM) dokumentiert und auf 9 Tafeln illustriert. In der Foraminiferen-Gesamtfauna dominieren Vertreter der Familie Nodosariidae mit den Gattungen Lenticulina, Astacolus, Citharina, Lingulina, Marginulinopsis, Nodosaria und Vaginulina. Mit der zweitgrößten Häufigkeit folgen die Familien Epistominidae, Textulariidae und Spirillinidae mit den Gattungen Epistomina, Spirillina sowie Reophax, Ammobaculites und Textularia. Die Arten Reophax sterkii, Triplasia althoffi, Verneuilinoides subvitreus, Nubeculinella bigoti, Dentalina filiformis, Saracenaria oxfordiana, Lingulina longiscata, Citharina flabellata, Palmula deslongchampsi, Vaginulina proxima, Ammodiscus asper, Ammodiscus siliceus, Triplasia bartensteini, Spirillina orbicula, Ophthalmidium carinatum, Tubinella inornata, Nodosaria fusiformis, Pyramidulina rara und Ramulina ascissa wurden erstmals in Gesteinen des Kachchh-Beckens nachgewiesen. Die dominierenden Taxa in den untersuchten Sedimenten sind epifaunale Formen, die einen hohen Sauerstoffgehalt im Bodenwasser benötigen. Infaunale, im Sediment lebende Arten treten dagegen etwas seltener auf. Diese lebten bevorzugt in sub- bis dysoxischen Milieus mit geringen Gehalten an gelöstem Sauerstoff im Bodenwasser und konnten auch Sauerstoffminima tolerieren. Aus der benthischen Foraminiferenfauna können folgende Rückschlüsse gezogen werden: • Die wichtigsten Parameter für die Verbreitung der Foraminiferen sind Substrat, Energieniveau und Sauerstoffgehalt. • Die höchste Diversität weisen die epifaunalen Vergesellschaftungen auf. • Mit zunehmender Sedimenttiefe nehmen Häufigkeit und Diversität ab. • Die Diversität der Kalkschaler ist höher als die der Sandschaler. • Minimale Diversitäten liegen in Stressmilieus mit geringen Sauerstoffgehalten vor. • Die hohen Werte des Evenness-Index weisen auf eine annähernd gleichmäßige Verteilung der benthischen Foraminiferen in den Profilen hin. • Epifaunale Arten werden von den physikochemischen Eigenschaften des Bodenwassers gesteuert. Sie sind auf partikuläres organisches Material und hohe Sauerstoffgehalte des Bodenwassers angewiesen. In der vorliegenden Arbeit wurden Probencluster gebildet, um Faunenassoziationen zu erfassen und danach die Umwelt- und Ablagerungsbedingungen zu rekonstruieren. Aus drei Profilen wurden 125 Proben für eine quantitative palökologische Analyse der Foraminiferen ausgewählt. Die W-mode Clusteranalyse zeigt eine große Ähnlichkeit zwischen den Proben, die sich in zwei Hauptcluster mit insgesamt sechs Subclustern gruppieren lassen. Die dadurch gebildeten Probengruppen stellen verschiedene Foraminiferenassoziationen dar, die sich beschreiben und weitgehend interpretieren lassen. • Assoziation A zeichnet sich durch hohe Anteile der Gattung Epistomina mosquensis aus. Diese Assoziation repräsentiert vollmarine Ablagerungsbedingungen mit normalmariner Salinität und guter Durchlüftung des Bodenwassers. • Assoziation B wird durchweg von Reophax metensis dominiert. Die Assoziation charakterisiert einen niedrig-energischen und teilweise sauerstoffarmen Sedimentationsraum. • Assoziation C wird stark von Dorothia prekummi dominiert und kennzeichnet vollmarine Bedingungen. • Assoziation D ist von Lenticulina subalata beherrscht und charakterisiert gutdurchlüftete Flachwasserbereiche. • Assoziation E wird von Spirillina polygyrata dominiert. Sie ist typisch für einen flachen Subtidalbereich unterhalb der Wellenbasis mit vollmarinen Bedingungen, normal mariner Salinität und gut durchlüftetem Bodenwasser. • Assoziation F zeichnet sich durch hohe Gehalte an Lenticulina quenstedti aus. Die Assoziation charakterisiert Bereiche, die überwiegend unterhalb der Schönwetter-Wellenbasis liegen und ein niedriges bis mittleres Sauerstoff-Niveau aufweisen. Aus einem Vergleich zwischen den Gehäusegrößen und der Häufigkeit von Lenticulina subalata und Epistomina mosquensis in den karbonatischen und siliziklastischen Sedimenten ergab sich, dass die Gehäuse von L. subalata und E. mosquensis in den Karbonaten größer sind als in den Siliziklastika. Die mitteljurassischen Ablagerungsräume des Kachchh-Beckens werden anhand der lithologischen und faunistischen Parameter rekonstruiert. Ferner werden die Foraminiferen-Vergesellschaftungen mit den von FÜRSICH et al. (2004) beschriebenen Makrofauna-Assoziationen verglichen. Aus diesen Untersuchungen ergaben sich folgende Schlussfolgerungen: • Die Ablagerungen im Jhura-Profil sind in flacherem Wasser sedimentiert worden als im Kamaguna-Profil und Jumara-Profil. • Die Mikro- und Makrofauna in diesen Profilen führt zu mehr oder weniger identischen palökologischen Schlussfolgerungen.
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Ortiz, Joseph D. "Planktic foraminifers of the California Current at 42��N : last glacial maximum and present." Thesis, 1995. http://hdl.handle.net/1957/23528.
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MOCNESS plankton tows, sediment traps and sedimentary material are used to determine
the linkage between bio-physical forcing and foraminiferal response over a range of time
scales from the event scale to the glacial interglacial cycle. The annually averaged planktic
foraminiferal fauna of the modem California Current is a diverse community composed of
individuals from subarctic, transitional, and subtropical foraminiferal assemblages. This
community is more diverse, but less abundant in total standing stock and shell flux than the
subarctic community of the Gulf of Alaska. The use of plankton tow and isotopic data
allow us to partition the foraminiferal community into shallow dwelling euphotic zone
species and deep dwelling sub-thermocline species. On both the event and seasonal time
scales, heterotrophic species were most abundant in cold, biomass rich coastal waters. In
contrast, species which harbored endosymbionts were more abundant in oligotrophic
waters with higher ambient light levels. During the Last Glacial Maximum (LGM), the
diverse modern fauna was replaced with a low diversity, high flux, heterotrophic
community similar to that of the modern Gulf of Alaska. Modern analog temperature
estimates suggest the California Current was roughly 3��C cooler during the LGM than
today. Coupled with oxygen isotopic results from G. bulloides, the surface thermal
structure implies an equatorward flowing glacial California Current at these sites. The
Polar Front thus remained north of these locations during the LGM. Comparison of glacial
G. bulloides carbon isotopes and shell accumulation rates with organic carbon flux
estimates implies the glacial California Current was (1) higher in nutrient content, (2) lower
in plankton biomass, and (3) lower in export carbon flux than its modem counterpart. This
description suggests that during the LGM the plankton community of the California Current
was very similar to the modern plankton community of the Gulf of Alaska.Graduation date: 1996
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Feldman, Andrew Howard Arnold Anthony Jay. "The evolutionary origin and development of the neogene planktonic foraminiferal globorotalia (truncorotalia) subgenus the mode and tempo of speciation and the origin of coiling direction reversals and dominance /." 2004. http://etd.lib.fsu.edu/theses/available/etd-04122004-160415.
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Thesis (Ph. D.)--Florida State University, 2004.Advisor: Dr. Anthony J. Arnold, Florida State University, College of Arts and Sciences, Dept. of Geological Sciences. Title and description from dissertation home page (viewed Aug. 27, 2004). Includes bibliographical references.
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Haynes, Laura. "The Influence of Paleo-Seawater Chemistry on Foraminifera Trace Element Proxies and their Application to Deep-Time Paleo-Reconstructions." Thesis, 2019. https://doi.org/10.7916/d8-x2x2-da06.
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The fossilized remains of the calcite shells of foraminifera comprise one of the most continuous and reliable records of the geologic evolution of climate and ocean chemistry. The trace elemental composition of foraminiferal shells has been shown to systematically respond to seawater properties, providing a way to reconstruct oceanic conditions throughout the last 170 million years. In particular, the boron/calcium ratio of foraminiferal calcite (B/Ca) is an emerging proxy for the seawater carbonate system, which plays a major role in regulating atmospheric CO2 and thus Earth’s climate. In planktic foraminifera, previous culture studies have shown that shell B/Ca increases with seawater pH, which is hypothesized to result from increased incorporation of borate ion (B(OH)4 -) at high pH; increasing pH increases the [B(OH)4 -] of seawater. However, further experiments showed that B/Ca responds to both pH and seawater dissolved inorganic carbon concentration (DIC), leading to the hypothesis that B/Ca is driven by the [B(OH)4 -/DIC] ratio of seawater. Because pH (and thus B(OH)4 -) can be determined via the δ11B composition of foraminiferal calcite, B/Ca therefore may provide an opportunity to determine seawater DIC in the geologic past.
The magnesium/calcium ratio (Mg/Ca) of foraminifer shells is a well-established proxy for seawater temperatures, where foraminiferal Mg/Ca increases at greater temperatures. However, foraminifera shell chemistry such as B/Ca and Mg/Ca ratios also depend on the major ion chemistry of seawater. For example, the seawater Mg/Ca ratio (Mg/Casw), which has increased significantly over the last 60 million years, is known to affect the sensitivity of the Mg/Ca proxy to temperature. In addition, the seawater boron concentration ([B]sw) has also increased across the Cenozoic. The dependence of B/Ca proxy relationships on Mg/Casw and [B]sw composition remains unknown.
During the Paleogene era (65-34 Ma), Earth’s climate was characterized by a number of rapid warming events termed ”hyperthermals”. Evidence from the sedimentary record suggests that hyperthermals were catalyzed by rapid carbon release and caused widespread ocean acidification and deep-sea deoxygenation. These hyperthermal events present the best geologic analog conditions to anthropogenic climate change, and their study can therefore help to illuminate how the Earth system responds to rapid carbon release and warming. Planktic foraminiferal B/Ca records from the largest hyperthermal event, the Paleocene-Eocene Thermal Maximum (PETM), show a large decrease, which agrees with the theory that ocean acidification should cause B/Ca to decline. However, the decrease is larger than can be reconciled from existing proxy calibrations conducted in modern seawater, begging the question of whether the low Mg/Casw of the Paleogene Ocean affected the sensitivity of B/Ca to the seawater carbonate system. Because there are also a number of outstanding uncertainties regarding the controls on B/Ca- including seawater [Ca] and shell growth rate, light intensity, and phosphate concentration- it is also possible that these factors contributed to the PETM B/Ca excursion. The influence of these additional parameters on B/Ca, as well as the influence of Mg/Casw, needs to be tested in controlled culture experiments.
To address these outstanding questions in proxy development, I conducted a series of culture experiments in three living planktic foraminifer species- Orbulina universa, Trilobatus sacculifer, and Globigerinoides ruber (pink). In order to refine our understanding of proxy controls on foraminiferal B/Ca, I investigated how foraminiferal B/Ca is affected by variable light intensity, growth rate (indirectly via seawater [Ca] manipulation), and seawater [B]. Subsequently I tested the influence of low seawater Mg/Ca, analogous to that of the Paleocene ocean, on B/Ca-carbonate chemistry relationships. In Chapters 2 and 3, I detail how my results support the notion that planktic foraminiferal B/Ca in these three symbiont-bearing species is driven by the B(OH)4 -/DIC ratio of seawater and is not compromised by growth rate effects. Furthermore, the sensitivity of B/Ca to B(OH)4 -/DIC is increased under low Mg/Casw in both O. universa and T. sacculifer. In Chapters 2 and 3, I hypothesize that this increased sensitivity is due to decreased cellular pH regulation under low Mg/Casw, leading to a greater sensitivity of the foraminiferal microenvironment’s carbon system to external forcing. I define new culture calibrations that can be applied to records from Paleocene seawater in Chapter 3, and use these calibrations to reconstruct surface ocean DIC and the overall size of the carbon system perturbation across the PETM in Chapter 4. Finally, in Chapter 5, I show how foraminiferal Mg/Ca responds to seawater Mg/Ca and the carbon system from these same experiments, with implications for accounting for carbon system influences on Mg/Ca from early Cenozoic proxy records.
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Chezem, Michelle A. "Foraminiferal paleoecology across the early to middle Eocene transition (EMET) of the western Caribbean." 2012. http://liblink.bsu.edu/uhtbin/catkey/1666209.
Full textAbstract:
Foraminiferal faunas across the early to middle Eocene transition (EMET) were studied from three locations in the western Caribbean: Calle G section in Cuba, ODP site 998 B the Cayman Rise, and ODP site 999 B the Colombian basin. There were three primary objectives of this project 1) to observe changes in physical and biological paleoceanographic parameters in the Western Caribbean, more directly in the Cayman Ridge and the Colombian Basin, by the use of planktonic foraminifera data, 2) determine the cause of an oxygen isotope anomaly seen in Cuba by Fluegeman (2007) and that is expected to be present in the Western Caribbean, and 3) determine if the anomaly is a local or a more widespread regional event. The Calle G section in northwestern Cuba consists of early to middle Eocene age foraminiferal chalks. The planktonic foraminiferal fauna at this section is characterized by subbotinids and acarininids but does not contain morozovellids. Oxygen isotopes were obtained across the EMET from the planktonic foraminiferan Acarinina collactea. The resultant curve shows widely fluctuating values during the early portion of the EMET with more stable values occurring in the middle Eocene. The foraminiferal paleoecologic index tau curve at the Calle G section produced is similar to the oxygen isotope curve. ODP site 998 B, Cayman Rise, contains a series of foraminiferal limestones across the EMET. Unlike the Calle G section, this interval contains an abundant planktonic foraminifera fauna including Morozovella. The Morozovella:Acarinina ratio studied at ODP site 998 shows high, fluctuating values in the early part of the EMET with low, stable values during the middle Eocene.ODP site 999 B in the Colombian Basin consists of a series of foraminiferal chalks throughout the EMET. Similar to ODP site 998 this location also has an abundant assemblage of planktonic foraminifera including Morozovella. Evidence supporting turbidities have been observed at this locale as layers of shell hash and large benthic foraminifera. The Morozovella:Acarinina ratio studied at ODP site 999 is similar to that of ODP site 998 showing a high fluctuating values in the early part of the EMET with low, stable values in the middle Eocene. The presence of fluctuating values of oxygen isotopes, tau, and the Morozovella:Acarinina ratio followed by stable values across the EMET may be related to a change in circulation patterns through the Caribbean caused by a developing oceanic gateway. The widely fluctuating oxygen isotope values in the latest Ypresian may also be related to an influx of freshwater in the North Atlantic associated with the coeval Azolla event in the Arctic Ocean.Department of Geological Sciences
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Layman, Thomas Bruce 1957. "Paleoenvironmental significance of benthic foraminiferal biofacies in the Yegua Formation (Middle Eocene), southeast Texas." 1987. http://hdl.handle.net/2152/20375.
Full textAbstract:
Foraminiferal data analysis and lithofacies analysis of a three-well transect through the Middle Eocene Yegua Formation in southeast Texas provide insights into the depositional and paleoenvironmental history of the Gulf of Mexico Basin. Vertical and downdip changes in the lithology of the Yegua Formation in the three wells represents the depositional environments of a delta system that prograded onto the continental shelf, updip from the shelf margin. Two progradational episodes and two marine transgressions of the Yegua delta system occurred within this interval of the Yegua Formation in southeast Texas. Factor analysis of benthic foraminiferal census data reveals five major recurring assemblages of benthic foraminifera. These assemblages, or biofacies, occupied environments ranging from marginal marine to normal marine, middle-to-outer shelf environments. The stratigraphic relationships of the five biofacies show paleoenvironmental complexities that are not readily apparent from the lithofacies analysis. Integration of lithologic data and nonforaminiferal paleontologic data with the foraminiferal data produces a detailed paleoenvironmental reconstruction of the Yegua shelf in dip direction. Comparison of the foraminiferal data from the Yegua Formation with modern foraminiferal data from the Gulf of Mexico indicates that several properties of modern foraminiferal assemblages are similar to the foraminiferal assemblages of the Yegua Formation. Generic predominance, species diversity, and planktic to benthic ratios of modem foraminiferal assemblages can be used to help determine the paleoenvironmental significance of the Yegua foraminiferal assemblages. These properties of modern foraminiferal assemblages are not exact analogs for Middle Eocene assemblages and should be applied with caution.text
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Murgese, Stefano Davide. "Late Quaternary palaeoceanography of the eastern Indian Ocean based on benthic foraminifera." Phd thesis, 2003. http://hdl.handle.net/1885/151812.
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Martinez, Jose Ignacio R. "Late pleistocene palaeoceanography of the Tasman Sea." Phd thesis, 1993. http://hdl.handle.net/1885/140125.
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Harrison, Michael Anthony. "The Uitoe Limestone of New Caledonia : a Middle Eocene syntectonic foralgal reef from the southwest Pacific." 2013. http://liblink.bsu.edu/uhtbin/catkey/1741645.
Full textAbstract:
A study of a poorly understood limestone unit was conducted to contribute temporal information necessary to unraveling a series of cryptic events for a complex geologic region containing economically important natural resources. Secondary objectives included understanding the environment of deposition and regional influences. Biostratigraphic and sedimentologic information observed from the Uitoé Limestone went to reconstructing the paleoenvironment, constraining the age of deposition and indicating the paleogeographic faunal associations. Facies associations indicate a middle ramp depositional setting common in many location in the Tethys Sea. Paleogeographic associations for the microflora and fauna indicate a Tethyan signature present but a lack of Australian influence. A combination of planktic and benthic foraminiferal assemblages for the region constrain the age of the Uitoé Limestone between the middle of the Lutetian and the Early Bartonian.Department of Geological Sciences
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(8790095), Abdullah Khan Zehady. "DATA MINING AND VISUALIZATION OF EARTH HISTORY DATASETS FROM GEOLOGICAL TIMESCALE CREATOR PROJECT." Thesis, 2020.
Find full textAbstract:
The Geologic TimeScale Creator (TSCreator) project has compiled a range of paleo-environmental and bio-diversity data which provides the opportunity to explore origination, speciation and extinction events. My PhD research has four major interconnected themes which include the visualization methods of evolutionary tree and the impacts of climate change on the evolution of life in longer and shorter timeframes: (1) Evolutionary range data of planktonic foraminifera and nannofossils over the Cenozoic era have been updated with our latest geological timescale. These evolutionary ranges can be visualized in the form of interactive, extensible evolutionary trees and can be compared with other geologic data columns. (2) A novel approach of integrating morphospecies and lineage trees is proposed to expand the scope of exploration of the evolutionary history of microfossils. It is now possible to visualize morphological changes and ancestor-descendant lineage relationships on TSCreator charts which helps mutual learning of these species based on genetic and bio-stratigraphic studies. (3) These evolutionary datasets have been used to analyze semi-periodic cycles in the past bio-diversity and characteristic rates of turnover. Well-known Milankovitch cycles have been found as the drivers of fluctuations in the speciation and extinction processes. (4) Within a shorter 2000-year time period, global cooling events might have been a factor of human civilization turnover. Using our regional and global cultural turnover time series data, the effect of climate change on human culture has been proposed. The enhancement of the evolutionary visualization system accomplished by this research will hopefully allow academic and non-academic users across the world to research and easily explore Earth history data through publicly available TSCreator program and websites.