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1
Arriaga, Cavalieri Maria Eugenia. "Patrones de supervivencia y recuperación de los macroforaminíferos después de la extinción en masa del límite Cenomaniense-Turoniense." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/394041.
Full textAbstract:
Los macroforaminiferos constituyen un grupo de organismos k-estrategas de abundante presencia en los ambientes de plataformas pocos profundas, tanto en la actualidad como en el registro fósil, siendo a su vez uno de los grupos más susceptible a cambios en el medio am¬biente.
Durante la transición Cenomanience – Turoniense (CTB), la cual coincide con un epi¬sodio global de depositación de sedimentos ricos en materia orgánica (Evento Anóxico 2 o Evento Bonarelli), los macroforaminíferos que poblaban las plataformas carbonatadas fueron dramáticamente afectados por el drástico cambio en las condiciones ambientales. Dicho cam¬bio generó la octaba mayor extinción de organismos marinos que se conoce, acabando con la comunidad de macroforaminíferos correspondiente al Ciclo de Maduración Global del Cretáci¬co medio (GCMC). En esta tesis se discuten los patrones de recuperación de los foraminíferos luego de esta extinción.
El trabajo ha sido realizado en dos paleobioprovincias contiguas: la del Tetis central, que aflora en los Apeninos meridionales, y la Pirenaica, que aflora en los Pirineos meridionales (Unidad Surpirenaica Central). En los Pirineos, al igual que en la mayoría de plataformas a nivel mundial, las aguas que cubrían las plataformas poco profundas del Cenomaniense sufrieron un proceso de eutrofización que condujo a la desaparición de los organismos productores de carbonato, trayendo como consecuencia el cese de la sedimentación carbonatada. Esta falta de sedimentación tiene como consecuencia un hiato sedimentario, el cual que se registra pre¬vio a la inundación de la plataforma (drowning platform). Mientras que la Plataforma Apení¬nica mantuvo una sedimentación carbonatada somera durante el tránsito Cenomaniense-Tu¬roniense, y a pesar haber sido colonizada por organismos cianobacteriales, algunos pequeños foraminíferos bentónicos fueron capaces de sobrevivir.
Este estudio sugiere que, a pesar de las diferencias depositacionales y paleogeográficas entre las dos áreas estudiadas, los patrones de recuperación fueron muy similares, de la si¬guiente manera: 1) la información genética de las formas k-estrategas se perdió en la extinción en masa; sin embargo cierta “herencia” se mantiene en las pequeñas formas oportunistas de los géneros Nezzazatinella, Cuneolina, Dictyopsella y Rotorbinella sobrevivientes a la extin¬ción. 2) la calibración cronoestratigráfica de las secciones de los Apeninos meridionales, reali¬zada mediante datos de estratigrafía isotópica de Carbono y Estroncio, indican que después de la crisis del CTB las primeras formas nuevas aparecen en el Turoniense inferior (parte superior) y Turoniense medio, representadas por las especies Moncharmontia apenninica y Pseudocy¬clammina spharoidea; aunque no es sino hasta el Turoniense medio-superior que aparecen Scandonea samnítica y Reticulinella kaeveri, formas relativamente más complejas. 3) en los
Pirineos, la reaparición de fauna somera de foraminíferos en el registro fósil no ocurre has¬ta el Turoniense medio-superior, luego de la recuperación de la sedimentación carbonatada, con la presencia de las especies Moncharmontia apenninica y Pseudocyclammina spharoidea además de las formas “heredadas” del Cenomaniense, apareciendo luego géneros complejos como Eofallotia. 4) en ambas áreas el inicio del “Ciclo de Maduración Global de la Comunidad de macroforminíferos del Cretácico superior fue aparentemente simultánea. No obstante, a partir del Turoniense medio-superior se manifiesta ya un cierto provincialismo, a través de la presencia de los géneros Scandonea y Reticulinella en la paleobioprovincia del Tethys central y representantes del grupo de los meandropsínidos en la paleobioprovincia pirenaica, provin¬cialismo que se será mucho más acentuado en las etapas posteriores de ciclo de maduración.Larger foraminifera are a k-strategists group extremely abundant in shallow water plat¬form environments, both in the recent and the fossil record. They represent one of the most sensitive marine organisms to environmental perturbations. During the Cenomanian-Turonian Boundary (CTB) interval, coinciding with a widespread episode of organic-rich sediments deposition (Oceanic Anoxic Event 2 or Bonarelli event), the larger foraminifera inhabiting the shallow environment were dramatically affected by a major paleoenvironmental conditions change. Such event finished with the middle Cretaceous Glo¬bal Community Maturation Cycle (GCMC). In this work we discuss the post-extinction recovery pattern. This works has been carried out in two neighboring paleoprovinces: Central Tethys, which outcrop at the southern Appenines, and the Pyrenean, outcrop located at the southern Pyrenees (Central Sud-pyrenean Unit). In the Pyrenees, like in most of the platforms, the water layer suffered an eutrophication process that leads demise the carbonate producer organisms, causing a stop on carbonate sedimentation. Such lack on sedimentation generates a sedimen¬tary hiatus perceptible in the stratigraphic record before the drowning episode. While the platform from southern Apennines was able to keep up on shallow carbonate sedimentation, and despite the colonization of cyanobacteria organisms, some small foraminifera were capa¬ble to survive. Here is suggest that even though the paleogeographic and depositional differences bet¬ween the studied areas, both present similar recovery patterns in the fallowing way: 1) The genetic information necessary for sustaining a k-strategy was lost with the extinction, but the “legacy” of larger foraminifera survived in the small r-strategist forms of Nezzazatinella, Cu¬neolina, Dictyopsella and Rotorbinella survivor genus. 2) chronostratigraphic calibration of Apenninic sections made by Strontium and Carbon Isotopic Stratigraphic data, indicates that the firth “newcomers ” appears during the upper part of lower Turonian with Moncharmontia apenninica and Pseudocyclammina spharoidea new species; but is not until middle-upper Tu¬ronian that more complex forms appears with Scandonea samnítica and Reticulinella kaeveri species. 3) In the Pyrenees, the shallow foraminiferal fauna reenter during the mid-upper Tu¬ronian after the carbonate sedimentation retrieval, represented by Moncharmontia apennini¬ca and Pseudocyclammina spharoidea species together with the “legacy” forms from Cenoma¬nian age; then also appear more complex genus as Eofallotia. 4) It seems like in both areas the Global Community Maduration Cycle of upper Cretaceous began simultaneously. However, from the middle-upper some sort of provincialism is noticeable with the presence of Scando¬nea and Reticulinella genus in the central Tethys, while the firth forms of meandropsinids are showns up for the Pyrenean realm, such paleoprovincialism considerably emphasizes during the latter stages of upper Cretaceous GCMC.
2
Silva, Cristiane Pakulski da. "Bioestratigrafia e paleoecologia de foraminíferos da Bacia de Barreirinhas, cretácio, margem equatorial brasileira." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/38528.
Full textAbstract:
O presente estudo integra informações bioestratigráficas e paleoecológicas obtidas através da análise de foraminíferos planctônicos e bentônicos recuperados dos sedimentos provenientes de cinco poços (1-MAS-1, 1-MAS-3A, 1-MAS-4A, 1-MAS-14 e 1-MAS-15) da Bacia de Barreirinhas, perfazendo um total de 127 amostras de calha preparadas e analisadas. Os sedimentos aqui analisados abrangem os andares Albiano superior ao Campaniano superior com registro geológico inserido nos grupos Caju (Albiano - Cenomaniano) e Humberto de Campos (Turoniano - Maastrichtiano). Através dos dados bioestratigráficos obtidos foi possível estabelecer sete biozonas de foraminíferos, de caráter local, com base na última ocorrência do táxon guia (LAD - Last Appereance Datum). O Albiano superior foi definido com base nas biozonas do foraminífero planctônico Ticinella primula Lauterbacher (1963) e foraminíferos bentônicos Lingulogavelinella albiensis Malapris (1965)-Gyroidina bandyi Trujillo (1960); o Cenomaniano inferior foi determinado através das biozonas do foraminífero planctônico Globigerinelloides bentonensis Morrow (1934) e foraminífero bentônico Coronorotalites aptiensis Bettenstaedt (1952); o Cenomaniano superior foi reconhecido através das biozonas do foraminífero planctônico Rotalipora appeninica Renz (1936) e foraminífero bentônico Gavelinella intermedia Berthelin (1880); o Campaniano superior foi determinado com base na biozona do foraminífero planctônico Heterohelix pulchra Brotzen (1936). Após a identificação da microfauna, foi possível reconhecer 108 espécies de foraminíferos pertencentes a cinco subordens: a Subordem Globigerinina, de foraminíferos planctônicos, é representada por 40 espécies e 15 gêneros; os foraminíferos bentônicos são compostos por 68 espécies e 48 gêneros, pertencentes as Subordens Rotaliina, Textulariina, Lagenina e Miliolina. Através da análise da assembléia de foraminíferos, foi possível traçar a CCD (Carbonate Compensation Depth - Profundidade de Compensação do Carbonato) nos poços e separá-los com base na profundidade em: distais (1-MAS-1 e 1-MAS-14) e proximais (1-MAS-3A, 1-MAS-4A e 1-MAS-15). Observou-se que a Bacia de Barreirinhas possui uma tendência geral transgressiva ao longo do Período Cretáceo, caracterizada por meio do influxo sedimentar através de variações climáticas, como o aquecimento global ocorrido neste período. Esta teoria é reforçada pela completa ausência de tecas calcárias, tanto de foraminíferos bentônicos, quanto planctônicos, associada à ocorrência exclusiva de bentônicos aglutinantes e silicosos (Reophax globosus) nos poços distais ao final do Período Cretáceo. Nos poços 1-MAS-3A, 1-MAS-4A e 1-MAS-15, a fauna de foraminíferos identificada apresenta adaptações morfológicas a condições de baixa oxigenação na coluna d'água, características normalmente observadas durante os Eventos Oceânicos Anóxicos (Oceanic Anoxic Event - OEA). Como exemplo destas adaptações morfológicas, foram identificadas três espécies pertencentes ao gênero Schakoina, que possui câmaras alongadas e a espécie Biticinella breggiensis, que possui câmaras bilobadas, sugerindo um aumento na produtividade primária, disponibilidade de nutrientes e paleoambientes depletados em oxigênio. Com base nestas informações foi possível identificar que um Evento Anóxico de caráter local tenha ocorrido durante o Albiano superior, registrado somente nos poços 1-MAS-3A e 1-MAS-4A, enquanto que o Evento Anóxico Global 2 foi registrado no poço 1-MAS-15.This study integrates biostratigraphic and paleoecological information obtained through of planktonic and benthic foraminifera analysis from sediment recovered from five wells (1-MAS-1, 1-MAS-3A, 1-MAS-4A, 1-MAS-14 and 1-MAS-15) of Barreirinhas Basin, making a total of 127 samples prepared and analyzed. The sediments analyzed here cover the upper Albian to upper Campanian stages with geological record inserted in the Caju (Albian - Cenomanian) and Humberto de Campos (Turonian - Maastrichtian) groups. Through the biostratigraphic data obtained it was possible to establish seven foraminiferal biozones, of local character, based on the last occurrence of taxon guide (LAD - Last Appereance Datum). The upper Albian was defined based on planktonic foraminifera biozones of Ticinella primula Lauterbacher (1963) and benthic foraminifera Lingulogavelinella albiensis Malapris (1965)-Gyroidina Bandy Trujillo (1960); the lower Cenomanian was determined through the planktonic foraminifera biozones of Globigerinelloides bentonensis Morrow (1934) and benthic foraminifera Coronorotalites aptiensis Bettenstaedt (1952); the upper Cenomanian was recognized through the planktonic foraminifera biozones of Rotalipora appeninica Renz (1936) and benthic foraminifera Gavelinella intermedia Berthelin (1880); the upper Campanian was determined based on the planktonic foraminifera biozone Heterohelix pulchra Brotzen (1936). After the identification of microfauna, was possible to recognize 108 species of foraminifera belonging to five suborders: the Suborder Globigerinina, of planktonic foraminifera, is represented by 40 species and 15 genera; the benthic foraminifera are composed of 68 species and 48 genera, belonging to the suborders Rotaliina, Textulariina, Lagenina and Miliolina. Through analysis of foraminifera assemblage it was possible to trace the CCD (Carbonate Compensation Depth) in the wells and separate them based on depth in: distal (1-MAS-1 and 1-MAS-14) and proximal (1-MAS-3A, 1-MAS-4A and 1-MAS-15). It was noted that the Barreirinhas Basin has an overall transgression during the Cretaceous Period, characterized by sedimentary influx through weather changes, like global warming that occurred during this period. This theory is enhanced by the complete absence of calcareous tests, both of benthic as planktonic foraminifera associated with the exclusive occurrence of agglutinating and arenaceous benthic (Reophax globosus) in the distal wells of the end of Cretaceous Period. In the wells 1-MAS-3A, 1-MAS-4A and 1-MAS-15, the foraminifera fauna identified presents morphological adaptations to conditions of low oxygen in the water column, features typically seen during the Oceanic Anoxic Event (OEA's). As examples of these morphological adaptations, was identified three species of the Schakoina genera, which has elongated chambers and Biticinella breggiensis species, which has bilobeted chambers, suggesting an increase in the primary productivity, nutrient availability and paleoenvironments depleted in oxygen. Based on this information it was possible to identify a local character anoxic events occurred during the upper Albian, recorded only in a well 1-MAS-3A and 1-MAS-4A, while the global anoxic event 2 was recorded in a well 1-MAS-15.
3
Zerfass, Geise de Santana dos Anjos. "Estudos paleoambientais com base em isótopos de carbono, oxigênio e estrôncio em foraminíferos do terciário da Bacia de Pelotas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/23713.
Full textAbstract:
A Bacia de Pelotas, localizada na porção sul da margem continental brasileira, foi formada a partir da fragmentação do supercontinente Gondwana e preenchida por sedimentos essencialmente siliciclásticos desde o Cretáceo. A ausência de rochas vulcânicas apropriadas para a datação através de métodos radiométricos na seção terciária da bacia e a abundância de microfósseis de parede calcária, constitui um cenário favorável para a utilização da razão isotópica de estrôncio visando à obtenção de dados cronoestratigráficos. Além dos microfósseis de parede calcária, a ocorrência conspícua de microfósseis de parede orgânica caracteriza esta seção como adequada para a realização de correlações biocronoestratigráficas. Uma síntese dos dados bioestratigráficos publicados é aqui apresentada com o intuito de verificar a ocorrência de descontinuidades temporais na sucessão sedimentar da bacia. Posteriormente, a avaliação da preservação das testas de foraminíferos foi realizada a fim de fornecer elementos para selecionar as amostras a serem utilizadas nas análises e verificar a consistência dos dados isotópicos. Foram reconhecidos quatro tipos de alterações diagenéticas em diferentes níveis estratigráficos da base para o topo: recristalização (neomorfismo), cimentação, recobrimento por filme oxidado e dissolução. Dados da razão isotópica de estrôncio, oxigênio e carbono e da razão Sr/Ca, foram obtidos a partir da análise de amostras provenientes de quatro poços. Adicionalmente, uma abordagem bioestratigráfica e paleoambiental foi possível com base no estudo dos foraminíferos e palinomorfos de dois intervalos testemunhados em dois poços, um na região emersa e outra na submersa, constituindo uma seção de referência para correlação. Com base no estudo dos testemunhos foi proposto um arcabouço estratigráfico de alta resolução, tendo sido identificado um hiato de 2 Ma na seção do mesomioceno e um evento transgressivo entre o meso e o neomioceno. Em uma abordagem mais ampla, o arcabouço cronoestratigráfico da seção do Paleogeno-Neogeno de quatro sondagens foi detalhado. Foram reconhecidos seis hiatos: (i) no Paleogeno, (ii) no eoeocenomesoeoceno, (iii) no mesoeoceno, (iv) entre o neoeoceno e o eoligoceno, (v) no eomioceno e (vi) entre o eomioceno e o meso/neomioceno. Os hiatos identificados, exceto aquele entre o eoeoceno e o mesoeoceno, foram interpretados como disconformidades associados a eventos globais. Uma queda do nível do mar a 10.4 Ma gerou uma disconformidade que pode estar relacionada ao início da deposição do Cone do Rio Grande. Quedas do nível do mar a nível global são as prováveis causas das descontinuidades reconhecidas em 18,5 Ma, 31,5 Ma e 40,5 Ma. O hiato identificado no eoeoceno-mesoeoceno (53-47,9 Ma) foi por sua vez interpretado como uma seção condensada. Do eoeoceno ao neoligoceno, uma tendência de resfriamento associada à abertura da Passagem de Drake foi registrada com base na curva de isótopos de oxigênio. Com base nos dados de δ13C observou-se uma tendência de aumento de produtividade do neoligoceno ao eomioceno, a qual provavelmente está associada a uma fase de aquecimento. Uma nova fase de resfriamento, relacionada ao restabelecimento da calota de gelo na Antártica, foi registrada na seção do neomioceno em ciclos de aproximadamente 400.000 anos.The Pelotas Basin, situated in the southern Brazilian Atlantic Margin, is filled with siliciclastic sediments deposited from Cretaceous to Holocene. The absence of volcanic strata appropriate to radiometric dating and the abundance of calcareous microfossils constitute a favorable scenario for the use of strontium isotope ratio to obtain chronostratigraphic data for the Tertiary section of the basin. Furthermore, the conspicuous occurrence of organic-walled microfossils makes this section suitable for biochronostratigraphic correlations. A synthesis of the biostratigraphic data published is presented in order to recognize discontinuities in the stratigraphic record. Afterward, the assessment of the foraminifera tests preservation was effectuated with the purpose of providing criteria to select the samples to be analyzed and verify the consistency of the isotopic data. Four types of diagenetic alterations were recognized in different stratigraphic levels, from the base to the top of the studied section: recrystallization, cementation, oxidized coatings and dissolution. Strontium, oxygen and carbon isotope ratios and Sr/Ca ratio were performed in foraminifera tests from four drill-holes. Foraminifera and palynomorphs recovered from cores of two wells located on onshore and offshore regions provided a biostratigraphic and paleoenvironmental information, constituting a reference section for correlation. Based on the core study, a highresolution biostratigraphic framework is proposed, in which a hiatus of 2 Ma is identified in the middle Miocene, as well as a transgressive event in the middle-late Miocene. In a broader approach, a chronostratigraphic framework is presented for the Paleogene-Neogene section of four drill-holes. Six hiatuses were recognized: (i) Paleocene, (ii) early-middle Eocene, (iii) middle Eocene, (iv) late Eocene - early Oligocene, (v) early Miocene, and (vi) early Miocene - middle/late Miocene. The identified hiatuses, except that of early-middle Eocene, were interpreted as disconformities in association with global events. A sea-level fall at 10.4 Ma may be related to the deposition of Rio Grande Cone. Global eustatic sea-level falls produced the disconfomities recognized at 18.5 Ma, 31.5 Ma and 40.5 Ma. The hiatus recognized in the early Eocene was interpreted as a condensed-section deposited between 53.7 and 47.9 Ma. From the early Eocene to the late Oligocene, a trend of cooling registered using oxygen and carbon isotopes may be related to the opening of the Drake Passage. Based on δ13C, a trend of increasing productivity probable driven by warming was observed from the late Oligocene to the early Miocene. Another cooling phase was registered in the late Miocene section which can be related to the reestablishment of the ice-sheet in Antarctica. This interval is punctuated of short-term cycles of approximately 400 ky.
4
Nagai, Renata Hanae. "Variações de paleoprodutividade na plataforma interna de Cabo Frio, RJ, durante o holoceno." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/21/21133/tde-24092009-111219/.
Full textAbstract:
Análises sedimentológicas, geoquímicas e microfaunísticas realizadas em um testemunho coletado na plataforma interna de Cabo Frio, permitiram a compreensão das variações de produtividade nos últimos 9.300 anos. Quatro fases foram reconhecidas, influenciadas por flutuações do nível relativo do mar e mudanças climáticas que ocorreram na margem continental sudeste Brasileira, durante o Holoceno. Antes de 7,0 kanos cal A.P., os dados apontam para baixa produtividade, sob condições de nível relativo do mar mais baixo e clima úmido. Entre 7,0 e 5,8 kanos cal A.P., há aumento na produtividade oceânica, num cenário de nível do mar em ascensão e condições climáticas mais úmidas. Produtividade similar à fase anterior marca o período de 5,8 a 2,8 kanos cal A.P., em condições de descida do nível do mar e clima mais seco. De 2,8 kanos cal A.P. até o presente, aumento na produtividade oceânica e condições hidrodinâmicas intensas, associados ao estabelecimento do processo de ressurgência em Cabo Frio, quando condições climáticas atuais são estabelecidas. A partir de 2,5 kanos cal A.P., observa-se intensificação do processo de ressurgência, controlada pela ação conjunta de ventos de NE mais intensos (associados a eventos El-niño e/ou a posição da Zona de Convergência Intertropical - ZCIT), meandramento da Corrente do Brasil - CB - e configuração atual da linha de costa.Sedimentological, geochemical and benthic foraminifera analyses carried out on a core sampled from the inner shelf of Cabo Frio, enabled us to identify different four productivity regimes related to sea-level fluctuations and/or climatic changes, that occurred in the southeastern Brazilian continental margin, during the last 9.3 kyr cal BP. Prior to 7.0 kyr cal BP, a lower productivity and less intense hydrodynamic regime occurred at lower sea levels and under drier climatic conditions. Between 7.0 and 5.8 kyr cal BP, relatively stronger local oceanic circulation and relatively high productivity were observed, in a scenario of rising sea levels and more humid conditions. From 5.8 to 2.8 kyr cal BP, bottom currents weakened and input of nutrients increased, with productivity levels similar to the previous phase at lower sea level and in a drier climate. From 2.8 kyr cal BP up to the present, stronger hydrodynamic conditions and a higher productivity regime linked to the establishment of the upwelling process in Cabo Frio. From 2.5 kyr cal BP to the present, upwelling enhancement has been recognized, resulting from the combined action of NE winds (related to El- Niño events and/or the Intertropical Convergence Zone - ITCZ - position), the meandering pattern of the Brazilian Current - BC - and present day coastline configuration.
5
Disaró, Sibelle Trevisan. "Caracterização da plataforma continental da Bacia de Campos (Brasil, SE) fundamentada em foraminíferos bentônicos recentes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/172465.
Full textAbstract:
Foraminíferos bentônicos vivos foram estudados visando a caracterização da plataforma continental da Bacia de Campos (sudeste do Brasil; 20.5°S - 24°S). Espécimes coletados no período seco/inverno/ressurgências menos frequentes de 2008 e no período chuvoso/verão/ressurgências mais frequentes de 2009 foram analisados para investigar padrões de distribuição espacial e temporal. As estações foram distribuídas em cinco isóbatas (25, 50, 75, 100 e 150 m), de nove transectos perpendiculares à linha de costa, totalizando 45 estações. Em cada estação, com busca-fundo e com delimitador 10 cm2 coletou-se três amostras de sedimento superficial (estrato 0-2 cm). Em laboratório, 20 cm³ de sedimento úmido por amostra foi lavado em peneira (63 μm), depois seco e triado na lupa. Material excedente foi estocado para contraprovas. Análises de Agrupamento e nMDS foram utilizadas para reconhecer grupos de estações e a Análise Canônica de Correspondência foi utilizada para investigar relações dos foraminíferos com dados ambientais. As variáveis-resposta quantitativas básicas foram biomassa e abundância; biomassa foi estimada por biovolume. A estrutura ecológica das associações (densidade, diversidade, dominância, equitatividade) foi estimada. Os dados foram avaliados visando caracterização da área e gestão ambiental da bacia. Registrou-se 519 táxons de foraminíferos. A análise integrada dos períodos identificou três áreas principais: (i) Plataforma interna (entre 25 e 50 m) - tem sedimentos predominantemente siliciclásticos, predominam espécies epifaunais, positivamente correlacionadas com areia, temperatura mais alta e concentração mais alta de clorofila-a; nela ocorrem Tiphotrocha concava, Bolivina paula, Nonionella sp.C, Discorbis williamsoni, Ammonia parkinsoniana, Ammonia tepida, Bolivina striatula, Textularia agglutinans, Angulogerina cf. A. jamaicensis Buliminella elegantissima, Paracassidulina nipponensis, Rectocibicides miocenicus, Placopsilina bradyi e muitas espécies dos seguintes gêneros Quinqueloculina, Textularia, Asterotrochammina, Eoeponidella, Porosononion, Polymorphina, Rotaliammina e Discorbis. (ii) Plataforma média/externa – (entre 75 e 100 m) - tem características predominantemente oligotróficas; areia, cascalho e lama, todos com alto teor de carbonato; as associações são compostas por Uvigerina auberiana, Technitella harrisii, Paratrochammina brasiliensis s.l., Planulina foveolata, Seabrookia earlandi, Svratkina spp., Pullenia spp., Discorbinella floridensis, Cibicidoides corpulentus, Stomatorbina torrei, Labrospira jeffreysii, Tetrataxiella ayalai, Mychostomina revertens, Amphicoryna scalaris, Globocassidulina rossensis, Ehrenbergina spinea, Spirotextularia floridana, Siphonina reticulata, Spirillina vivipara, Patellina corrugata e algumas espécies de Astrononion, Fissurina e Lenticulina entre outras. (iii) Área de ressurgências – predomínio de espécies infaunais positivamente correlacionadas com lama, feofitina-a e carbono orgânico total; a associação é composta por muitos rotalídeos pequenos como Bulimina marginata, Pappina compressa, Angulogerina angulosa, s.l., Alabaminella weddellensis, Bolivina fragilis, Bolivina ordinaria, Nonionella stella, Hopkinsina pacifica, Bolivinellina translucens, Stainforthia complanata, Bulimina patagonica, Hanzawaia concentrica, Gyroidina umbonata, Nonionella opima, Epistominella exigua, Cassidulina carinata, Fursenkoina pontoni e Nonionella atlantica; e alguns aglutinantes como Adercotryma glomeratum, Lagenammina atlantica, Ammoscalaria pseudospiralis, Reophax scorpiurus, Sepetibaella sepetibaensis, Labrospira crassimargo, Reophax pauciloculatus, Leptohalysis scottii, Textularia ? torquata e Reophax arayaensis e milliolídeos como Quinqueloculina sabulosa, Quinqueloculina atlantica s.l. e Pyrgo nasuta. A distribuição espacial dos foraminíferos é determinada pela profundidade, sedimento (tamanho de grão e conteúdo de carbonato) e disponibilidade de alimento. Foraminíferos fitodetritívoros indicaram áreas de ressurgência em Cabo Frio, Cabo de São Tomé e também ao norte da área estudada. A biomassa na plataforma interna é similar à de outras áreas investigadas, mas os valores da plataforma média e externa são mais altos que o esperado para uma região oligotrófica, sazonalmente mesotrófica. As curvas ABC indicaram a isóbata de 25 m como a mais perturbada da plataforma, especialmente durante o período chuvoso quando recebe maior aporte da drenagem fluvial e pluvial, talvez amplificada por contaminantes antropogênicos. Área com ressurgência mostraram perturbação moderada pelo método das curvas ABC; provavelmente trata-se apenas de perturbação natural, causada pelo incremento de produção primária. O estudo aporta dados para a gestão ambiental e a reconstrução paleoambiental.Spatial and seasonal differences over the continental shelf and along the shelf break edges of Campos Basin, southeastern Brazil (20.5°S - 24°S) were investigated during 2008 (downwelling setting/dry/winter) and 2009 (upwelling setting/rainy/summer), based on living benthic foraminiferal assemblages, as part of the “HABITATS Project - Evaluation of the Environmental Heterogeneity of the Campos Basin, Brazil”. The assemblages and their relationship with environmental variables were studied to support the research and development activities of PETROBRAS, the Brazilian state-owned oil Company. The sampling design consisted of nine transects (45 stations) perpendicular to the coastline. Three replicates were taken from each station using a modified grab that performs as a box corer. The surface (0-2 cm) bottom sediment was collected (10 cm x 10 cm), fixed with 4 % formaldehyde buffered solution, stained with Bengal Rose, washed and sieved through a 63 μm mesh. Of the 200 cm3 of each replicate, 20 cm³ were analyzed and the remainder stored for retesting. Foraminiferal assemblages were recognized using cluster analysis, indicator species analysis and nonmetric multidimensional scaling. Spatial and temporal patterns of the foraminiferal assemblages were identified and the ecological structure (density, diversity, dominance, equitability) of these assemblages investigated. Foraminiferal biomass was estimated by measuring biovolume. The correlations of biotic and abiotic parameters were evaluated using canonical correspondence analysis. A total of 519 foraminiferal taxa were recorded. Spatial distribution responds to depth, sediment (grain size and carbonate content) and food availability. Cluster analysis with integrated periods allowed the recognition of three distinct areas: (i) an Inner shelf (25 – 50 m) area positively correlated with sand, higher temperature and higher chlorophyll-a content; it was occupied by Tiphotrocha concava, Bolivina paula, Nonionella sp. C, Discorbis williamsoni, Ammonia parkinsoniana, Ammonia tepida, Bolivina striatula, Textularia agglutinans, Angulogerina cf. A. jamaicensis, Buliminella elegantissima, Paracassidulina nipponensis, Rectocibicides miocenicus, Placopsilina bradyi and species of Quinqueloculina, Textularia, Asterotrochammina, Eoeponidella, Porosononion, Polymorphina, Rotaliammina and Discorbis. (ii) a Medium/outer shelf (75 – 150 m) area is composed by two subgroups correlated with depth and elevated carbonate levels; its species association includes Uvigerina auberiana, Technitella harrisii, Paratrochammina brasiliensis s.l., Planulina foveolata, Seabrookia earlandi, Svratkina spp., Pullenia spp., Eponides antillarum, Discorbinella floridensis, Cibicidoides corpulentus, Stomatorbina torrei, Labrospira jeffreysii, Tetrataxiella ayalai, Mychostomina revertens, Amphicoryna scalaris, Globocassidulina rossensis, Ehrenbergina spinea, Spirotextularia floridana, Siphonina reticulata, Spirillina vivipara, Patellina corrugata and some species from Astrononion, Fissurina and Lenticulina. (iii) an Upwelling area is positively correlated with phaeopigment (phytodetritus), mud and total organic carbon; this group includes abundant small rotalids such as Bulimina marginata, Pappina compressa, Angulogerina angulosa, s.l., Alabaminella weddellensis, Bolivina fragilis, Bolivina ordinaria, Nonionella stella, Hopkinsina pacifica, Bolivinellina translucens, Stainforthia complanata, Bulimina patagonica, Hanzawaia concentrica, Gyroidina umbonata, Nonionella opima, Epistominella exigua, Cassidulina carinata, Fursenkoina pontoni and Nonionella atlantica, and such agglutinated foraminifers as Adercotryma glomeratum, Lagenammina atlantica, Ammoscalaria pseudospiralis, Reophax scorpiurus, Sepetibaella sepetibaensis, Labrospira crassimargo, Reophax pauciloculatus, Leptohalysis scottii, Textularia ? torquata, Pseudobolivina fusiformis and Reophax arayaensis, and some miliolids (Quinqueloculina sabulosa, Quinqueloculina atlantica s.l. and Pyrgo nasuta). During the upwelling period the South Atlantic Coastal Waters enlarged its influence to include not only the Cape Frio area, but also an area at about 75 meters depth off Cape Sao Tome. Biomass values at the inner shelf agreed with available published data, but on the middle and outer shelf the values are higher than expected for an oligotrophic, seasonally mesotrophic basin. The ABC curves indicate the 25 m isobath as the most disturbed one and recognize a moderated disturbance in the upwelling area. During rainy season the 25 m isobath is disturbed by natural eutrophication phenomena that may be significantly amplified by anthropogenic activities. This study provides data for the monitoring plan for the area and for paleoenvironmental reconstructions.
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Bowen, Powell Jacqueline. "Larger Foraminiferal Biostratigraphy, Systematics And Paleoenvironments of The Avon Park Formation and Ocala Limestone, Highlands County, Florida." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/288.
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This study investigates the use of larger foraminifera in determining the biostratigraphy of the Avon Park Formation and the Ocala Limestone in central Florida. Sedimentary rocks of the Avon Park Formation are the oldest exposed deposits in the state of Florida, and together with the Ocala Limestone comprise a part of the confining unit of the Floridan Aquifer, a major source of Florida’s water supply. Material from the ROMP 29A core collected by the U. S. Geological Survey was evaluated and compared to previous studies of the biostratigraphy of the formations. The larger foraminifera of the Avon Park Formation were examined in thin section, and those of the Ocala Limestone were free specimens. The larger foraminifera from both units were described and identified, and the biostratigraphy determined. The morphological features of the larger foraminifera of the Ocala Limestone were measured and analyzed at various depths within the ROMP 29A core. The Avon Park Formation contains predominantly the shallow-water, conical foraminifera Fallotella cookei, Fallotella floridana, Pseudochrysalidina floridana, Coleiconus christianaensis, Coleiconus sp. A, Coskinolina sp. A, Coskinolina sp. B, Fallotella sp. A, Fallotella sp. B, Fabularia vaughani and larger miliolids. The Ocala Limestone contains a different, deeper water assemblage that included the larger foraminifera Heterostegina ocalana, Lepidocyclina ocalana varieties, Lepidocyclina chaperi, Lepidocyclina pustulosa, Nummulites willcoxi, Nummulites striatoreticulatus, Nummulites floridensis and Pseudophragmina spp. A, B, and C. The age of the Avon Park Formation was corroborated by the occurrence of the biomarker echinoid Neolaganum dalli as Eocene, and the Ocala Limestone also contained Eocene larger foraminifera with Eocene to possibly Oligocene calcareous nannofossils. The distribution of the larger foraminifera of the Avon Park Formation was correlated with the subtidal and peritidal zones of the continental shelf. Analyses of variance showed that the changes in measurements of the morphology in Heterostegina ocalana, Lepidocyclina spp. and Nummulites spp. were correlated with change in the depositional environments.
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Mayer, Michaela. "Zur Ökologie der Benthos-Foraminiferen der Potter Cove (King George Island, Antarktis) = Ecology of benthic foraminifera in the Potter Cove (King George Island, Antarctica) /." Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2000. http://www.gbv.de/dms/bs/toc/314065083.pdf.
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Varhelyi, Aron. "Quaternary Arctic foraminiferal isotopes: species reliability and palaeoceanographic application." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-158047.
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To investigate whether foraminiferal stable isotope (δ18O/δ13C) variations have potential as a chronostratigraphic tool in the Arctic Ocean, this thesis presents new δ18O/δ13C data from five marine sediment cores. Three of those are downcore analyses (PS92/54-1; TC/PC-03; PC-07) and the remaining two are core top analyses (PC-04; PC-08). Seven species of benthic foraminifera (Cassidulina neoteretis, Cibicides lobatulus, Cibicidoides wuellerstorfi, Oridorsalis tener, Quinqueloculina arctica, Stainforthia concava and Triloculina sp.) and one planktic (Neogloboquadrina pachyderma sinistral) were compared against physical properties data, foraminifera counts and existing age models. The stable isotopic data reveal species-specific niches, resulting from vital effects and habitat preferences. As changes in δ13C mainly are related to palaeoproductivity and ocean/atmosphere gas exchange, and has limited use as a dating tool, the focus has been to create high-resolution downcore δ18O records that can be compared to a global benthic stack. Cibicidoides wuellerstorfi is found to be the most common benthic foraminiferal species in the central Lomonosov Ridge cores (TC/PC-03 and PC-07) whereas C. neoteretis and N. pachyderma are most common at the Yermak Plateau (PS92/54-1). Usefulness of C. wuellerstorfi in the central Lomonosov Ridge cores is limited due to low amplitude changes in δ18O over periods interpreted to cover several Marine Isotope Stages. A similar issue was observed in C. neoteretis δ18O on the Yermak Plateau (PS92/54-1). There, C. neoteretis abundances were low during interglacials. Instead, planktic N. pachyderma δ18O at the Yermak Plateau site (PS92/54-1), more closely than any analysed benthic species, resembled the global benthic δ18O stack. This implies potential of N. pachyderma δ18O as a chronostratigraphic tool in this region of the Arctic. Using N. pachyderma δ18O to correlate distal cores in the Arctic Ocean would demand addressing the issues of regional differences in pelagic δ18O, varying calcification depths and poor preservation. Addressing why the range of variability differs between sites in the same MISs is crucial, before attempting to stack downcore δ18O from the relatively abundant Arctic benthic species C. neoteretis.Med siktet på att undersöka huruvida variationer i stabila isotopvärden (δ18O/δ13C) hos foraminiferer har potential som dateringsredskap i Arktiska Oceanen, presenteras härmed ny δ18O/δ13C data från fem marina sedimentkärnor. Tre kärnor analyseras på längden (PS92/54-1; LOMROG III TC/PC-03 och PC-07) medan två analyser begränsas till kärnornas toppskikt (LOMROG I PC-04 och PC-08). Resultat från sju olika arter av bentoniska foraminiferer (Cassidulina neoteretis, Cibicides lobatulus, Cibicidoides wuellerstorfi, Oridorsalis tener, Quinqueloculina arctica, Stainforthia concava and Triloculina sp.) och en planktonisk (Neogloboquadrina pachyderma sinistral) har jämförts mot data som baserats på kärnornas fysiska egenskaper, mängden foraminiferer och befintliga åldersberäkningar. De nya isotopresultaten avslöjar nischer som är specifika för varje art och som, förutom isotopvärdena i det omkringliggande havsvattnet, är beroende av varierande fraktioneringseffekter samt habitatpreferenser. Förändringar i δ13C är mestadels avhängigt paleoproduktivitet och gasutbyte mellan atmosfär och hav. Det har därför begränsad användning som dateringsredskap. Fokus har istället legat på att skapa högupplöst δ18O data som kan jämföras med en global δ18O ’stack’. Cibicidoides wuellerstorfi är den vanligast förekommande arten i TC/PC-03 och PC-07 medan C. neoteretis och N. pachyderma har flest förekomster i PS92/54-1. I den senare kärnan saknas C. neoteretis under perioder där förändringar i δ18O antas vara stora (interglacialer). Istället är det δ18O hos planktoniska N. pachyderma som i högst grad efterliknar en global bentonisk ’stack’. Dessa resultat antyder att N. pachyderma potentiellt kan användas som lokalt dateringsverktyg. För att kunna korrelera mot mer avlägsna sedimentkärnor i Arktiska Oceanen med hjälp av δ18O från N. pachyderma, så behöver hänsyn tas till regionala skillnader i pelagial δ18O, varierande kalcifieringsdjup och dålig bevaring av foraminifererna. Det är viktigt att adressera varför det finns en amplitudskillnad mellan olika sedimentkärnor för samma tidsperioder, innan försök görs att sammanfoga δ18O resultat från den vanligt förekommande Arktiska bentoniska arten C. neoteretis.
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Licari, Laetitia. "Ecological preferences of Benthic Foraminifera in the Eastern South Atlantic : distribution patterns, stable carbon isotopic composition, and paleoceanographic implications = Ökologische Ansprüche benthischer Foraminiferen im östlichen Südatlantik /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2006. http://www.gbv.de/dms/bs/toc/514912308.pdf.
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Kuhn, Winfried. "Paleozäne und untereozäne Benthos-Foraminiferen des bayerischen und salzburgischen Helvetikums - Systematik, Stratigraphie und Palökologie /." München : F. Pfeil, 1992. http://catalogue.bnf.fr/ark:/12148/cb37429165g.
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Hurley, John Vincent. "Late-middle Eocene glacioeustacy : evidence from stable isotopes and foraminifera of the the [sic] Planktonic foraminiferan zone P14 (Truncorotaloides rohri zone), Mossy Grove Core, Hinds County, Mississippi." Virtual Press, 1999. http://liblink.bsu.edu/uhtbin/catkey/1117851.
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Glacioeustatic control of a late-middle Eocene oxygen isotope record is evident from the comparison of such a record with an independent proxy for sea-level. The data, δ18O and planktonic:benthic foraminifera ratios, were determined from samples of the Mossy Grove Core, Hinds County, Mississippi. The temporal order of magnitude for the glacioeustatic cycles, while smaller than two other orders of sea level change identified from this sedimentary package, is comparable to those associated with Milankovitch cycles. Refinement of the sample interval’s sequence statigraphy recognizes a Healing Phase Unit and allowed for identification of the time stratigraphic condensed section. Identification of the condensed section allows for the correlation of this sequence to other sections in the Gulf Coast.Department of Geology
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Leiter, Carola. "Benthos-Foraminiferen in Extremhabitaten." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-95510.
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Brückner, Sylvia [Verfasser]. "Climatic and hydrographic variability in the late Holocene Skagerrak as deduced from benthic foraminiferal proxies = Klimatische und hydrographische Variabilität im holozänen Skagerrak, abgeleitet aus benthischen Foraminiferen / Sylvia Brückner." Bremenhaven : Alfred- Wegener-Inst. für Polar- und Meeresforschung, 2008. http://d-nb.info/997391057/34.
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Lundquist, Jason James. "Foraminiferal biostratigraphic and paleoceanographic analysis of the Eagle Ford, Austin, and Lower Taylor groups (Middle Cenomanian through Lower Campanian) of central Texas /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Sanchez, Rios Maria Antonieta Guadalupe. "Foraminifères planctoniques et nannoplancton calcaire de quelques sites du Crétacé supérieur mexicain et sud-pyrénéen /." Toulouse : Université Paul Sabatier, Laboratoire de géologie sédimentaire et paléontologie, 1989. http://catalogue.bnf.fr/ark:/12148/cb35712901s.
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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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Ferguson, Julie E. "Palaeoclimate from foraminifers and molluscs in the Mediterranean." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547592.
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Caromel, Aude Genevieve Marcelle. "Form and function in planktic foraminifera." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.628998.
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Planktic foraminiferal tests and their morphology have been the subject of extensive study for biostratigraphy and palaeoenvironmental reconstructions. Iterative evolution of morphological designs and correlations between morphology and environmental parameters suggest either fundamental intrinsic constraints on form , or a functional control, or both. Yet the adaptive significance of the test morphologies in terms of these constraints has never been rigorously explored, and is the focus of this thesis. The developmental and growth constraints delimiting the scope of action for evolution were determined through ontogenetic reconstructions based on SRXTM scans. Differences in growth patterns between the globigerinid and globorotalid groups imply a different potential for diversification. Different metabolic processes dominate growth at different stages of ontogeny due to changes in surface area-to-volume ratios, so mechanisms of evolution responding to environmental factors may change depending on when they occur in ontogeny. Imposed on these are constructional considerations, which were gauged through estimation of coiling patterns through ontogeny from the reconstructions. Coiling in early ontogeny is constrained across all species to maximise lateral growth. From the neanic stage, changes in coiling occur to accommodate new chamber shapes, and are modulated by the migration of the aperture. Developmental processes of evolution must therefore operate within this framework. Computational fluid dynamic simulations were used to assess the functional role of the test in adjusting settling velocity, by varying morphological and water parameters independently. The range of evolutionary options open to foraminifera is a result of trade-offs between changes in size, shape and density, and environmentally required fluctuations can easily be accommodated by the natural within-population variability. The findings of this thesis imply that, in the compromise between function and constraints acting with the environment to define adult morphology and diversification, intrinsic factors are likely to play a more important role than function in plank tic foraminifera.
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Toth, Emoke. "Changements paléoenvironnementaux dans la Parathéthys Centrale pendant le Samartien (Miocène moyen) : étude paléontologique de microfaunes et analyses géochimiques." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00843092.
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Les changements paléoenvironnementaux se produisant pendant le Sarmatien dans la Paratéthys Centrale ont été reconstitués par l'étude des foraminifères (36 espèces) et des ostracodes (28 espèces) de deux forages, combinée à une analyse géochimique de leurs squelettes calcitiques, des coquilles aragonitiques de gastéropodes et des dents phosphatiques de rongeurs.La composition de la microfaune indique que la connexion entre la Paratéthys et la Méditerranée est interrompue ou réduite à la base du Sarmatien mais qu'un bras de mer persiste entre Paratéthys Centrale et Paratéthys Orientale jusqu'à la fin du Sarmatien. Le Sarmatien inférieur est caractérisé par des eaux saumâtres peu profondes (maximum 80 m), bien ventilées, des températures stables (~ 15°C), un riche couvert végétal (algues et/ou phanérogames) et des efflorescences phytoplanctoniques périodiques. Un événement transgressif y est observé (TST de 3ème ordre; TB 2.6 du cycle global). Les changements faunistiques qui se produisent à la limite entre Sarmatien inférieur et moyen sont expliqués par un évènement de type HST accompagné de conditions dysoxiques. A la fin du Sarmatien moyen, une baisse du niveau marin relatif d'environ 50 m se produit et des eaux tempérées chaudes, plus saumâtres (17-23‰) et bien ventilées se mettent en place. Après un court épisode régressif, une connexion est rétablie entre la Paratéthys et la Méditerranée au début du Sarmatien supérieur. Des eaux chaudes (15-21° C), bien ventilées, correspondant à des lagunes marines et des marécages avec de fortes variations de la salinité (15-43 ‰) s'installent alors avant un isolement ultime de la Paratéthys qui se produit à la fin du Sarmatien.
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Birse, S. E. A. "Experimental and computational studies on foraminiferal calcite." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596662.
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In this thesis, the effect of dissolution on the chemistry and structure of perforate planktonic foraminiferal tests was investigated. Atomistic simulations were undertaken to study the energetics of magnesium ions in calcite and their structural ordering in the {104} surface. Shell mass, δ18Oc and Mg/Ca measurements were obtained on core-top tests of foraminifera from depth transects in the Indian and Pacific oceans. The degree to which dissolution biased the temperature determined from δ18Oc and Mg/Ca measurements was found to be similar for G. sacculifer and G. ruber but greater for the Mg/Ca-temperature estimates for P. obliquiloculata and N. dutertrei. Corrections to the Mg/Ca ratios based on core-top depth, bottom water carbonate ion concentration, and shell mass were developed. For all species, bottom water carbonate ion concentration provided the best correction for the dissolution artifact. Crystallinity of the planktonic foraminiferal tests was investigated using x-ray powder diffraction from the {104} plane of calcite. Species offsets in crystallinity were attributed to differences in test structure, in particular the proportions of primary to secondary calcite composing the test wall. A correlation between tests which had undergone increased dissolution and a narrowing of the 104 Bragg peak was observed. This change was attributed to the preferential removal of smaller crystallites (the primary calcite). The crystallinity of undissolved tests correlated with growth rate. Faster test calcification could broaden the 104 Bragg peak because overall smaller crystallites were deposited or because more primary calcite was initially deposited. An empirical potential set was generated for calcium carbonate. Trends in metal cation defect energies between calcite and aragonite stemmed from the differences in bulk geometries. The {104} calcite surface, in vacuo and hydrated, was generated from the same potential set. Surface relaxation of the in vacuo surface was investigated by calculating within layer polarization and between layer strain.
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Barker, S. "Planktonic foraminiferal proxies for temperature and pCO2." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596364.
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The thesis aims to describe developments in the uses of planktonic foraminiferal calcite for oceanographic applications, specifically Mg/Ca ratios and foraminiferal shell weights as proxies for calcification temperature and paleo-pCO2 respectively. Sample preparation for the analysis of Mg/Ca and Sr/Ca ratios in foraminiferal calcite is investigated with the aim of defining a method that will give reproducible results and minimise signal contaminations. Each step of the cleaning procedure is scrutinised in order to gauge which are most important and which may be omitted as unnecessary and potentially detrimental to the elemental measurements being made. Success in the application of Mg/Ca-thermometry depends on the ability to quantify and compensate for any alteration of the primary signal after deposition. Compositional variations in foraminiferal calcite may be associated with partial dissolution at the seaflow. Investigation is made into the excessive scatter observed within a latitudinal transect of core-top Mg/Ca and Sr/Ca ratios and attributed to partial dissolution. Possible means of correcting or minimising the effects of such alteration are investigated and assessed. Recent interest in planktonic foraminiferal shell weight loss as a proxy for dissolution, and as such a potential means of quantifying compositional variability, demands investigation into the possibility that initial shell weight may not be constant. It is demonstrated that considerable variability does occur in the shell weights of several species of planktonic foraminifera in the modern surface ocean. It is proposed that initial shell weight is a function of calcification rate and controlled ultimately by the carbonate ion concentration, [CO3=], of ambient seawater during calcification. A first attempt is made to calibrate the effects of [CO3=] on shell weight in the modern ocean. The potential effects of anthropogenic atmospheric CO2 increases on marine calcification are then synthesised using the mineral relations between [CO3=] and calcification rate.
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Lea, David Wallace. "Foraminiferal and coralline barium as paleoceanographic tracers." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/54332.
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Pearson, Paul Nicholas. "Evolution and phylogeny of Palaeogene planktonic foraminifera." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386154.
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Seears, Heidi. "Biogeography and phylogenetics of the planktonic foraminifera." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/11879/.
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The planktonic foraminifera are a highly abundant and diverse group of marine pelagic protists that are ubiquitously distributed throughout the worlds’ oceans. These unicellular eukaryotes are encased in a calcareous (CaCO3) shell or ‘test’, the morphology of which is used to identify individual ‘morphospecies’. The foraminifera have an exceptional fossil record, spanning over 180 million years, and as microfossils provide a highly successful paleoproxy for dating sedimentary rocks and archiving past climate. Molecular studies, using the small subunit (SSU) ribosomal (r) RNA gene are used here to investigate the biogeographical distributions and phylogenetic relationships of the planktonic foraminifera. Biogeographical surveys of two markedly different areas of the global ocean, the tropical Arabian Sea, and the transitional/sub-polar North Atlantic Ocean, revealed significant genotypic variation within the planktonic foraminifera, with some genetic types being sequenced here for the first time. The foraminiferal genotypes displayed non-random geographical distributions, suggestive of distinct ecologies, giving insight into the possible mechanisms of diversification in these marine organisms. The ecological segregation of genetically divergent but morphologically cryptic genetic types could, however, have serious repercussions on their use as paleoproxies of past climate change. Phylogenetic analyses of the foraminifera based firstly on a partial ~1,000 bp terminal 3´ fragment of the SSU rRNA gene, and secondly on the ~3,000 bp almost complete gene supported the hypothesis of the polyphyletic origins of the planktonic foraminifera, which appear to be derived from up to 5 separate benthic ancestral lineages. The almost complete gene is sequenced here in the planktonic taxa for the first time, though amplification was problematic. In a first step to addressing a pressing need for new genetic markers to support data gained from the SSU rRNA gene, a culture system was established for the benthic foraminifera, in order to provide a reliable source of DNA for EST library construction or full genome sequencing. Finally, to overcome difficulties associated with the PCR amplification of the foraminifera, a new lysis buffer and DNA extraction procedure was developed. A highly successful buffer was created, allowing high quality DNA to be extracted from foraminiferal specimens, whilst leaving the delicate calcitic shell intact for morphological reference.
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Ward, Juliette Natalie. "Foraminifera as proxiles for monitoring organic pollution." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398830.
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Al-Sayigh, Abdul Razak Siddiq. "Lower Tertiary Foraminifera from south east Oman." Thesis, Aberystwyth University, 1999. http://hdl.handle.net/2160/1a8d5b93-df4b-412e-aecb-38c02de78e03.
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Over 250 samples were collected over three field seasons from the SE Oman Mountains. Fortyone species of planktonic Foraminifera (belonging to 7 genera) and twenty-eight species of larger benthonic Foraminifera, (belonging to 13 genera) are figured (both by SEM and optical photography) from the Wadi Musawa and Wadi Suq sections. Nine planktonic foraminiferal zones are formally recognised between the Upper Palaeocene(P 4) and upper Middle Eocene (P14). The known stratigraphic distribution of these species was used to recognise the zones P 5, P8-P9 as equivalentt o standard zones of Blow, 1969,1979, whilst strata considered generally equivalent to P4 and PIO-PI4 in the Wadi Musawa section are zoned on the basis of the local range. Younger sediments can only be dated on larger Foraminifera. A possible hiatus representing the planktonic zones P 6/P7 is tentatively identified. Fifteen lithostratigraphic units are recognised and formally described from three formations: the Abat Formation( units A-D), the Musawa Formation (units E-L) and the Tahwah Formation (units M-0). The ages of the Abat and Musawa formations are redefined and are shown to be significantly older than previously published. Biostratigraphical and palaeoenvironmental data from both the planktonic and the larger Foraminifera has been used in conjuction with the lithostratigraphy to construct a sequence stratigraphy, in which several cycles have been recognised. Some of these cycles may correlate with the global sea-level cycles of Haq et al. (1987) and include TA2.3 and TAM, Whilst others are local due to tectonically induced regressive and transgressive events. Information not only from the Foraminifera but also from radiolaria, ostracods and molluscs has been used to reconstruct the palaeoenvironment for the Omani Palaeogene. Parts of the Lower and Middle Eocene contain in-situ larger Foraminifera indicating deposition in a shelf (dominantly mid to outer) setting. During the late Palaeocene, most of the early Eocene, part of the middle Eocene, and the entire late Eocene/early Oligocene mixed assemblages of planktonics and shallow water benthonics were the dominant Foraminifera. The occurrence of the these two assemblages in deepwater sediments indicates a substantial period of time in which penecontemporaneous uplift and resedimentation of carbonate shelf deposits into deeperwater occurred. A number of new larger and smaller benthonic Foraminifera are described and one planktonic foraminifer renamed.
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Coxall, Helen Katherine. "Hantkeninid planktonic foraminifera and Eocene palaeoceanographic change." Thesis, University of Bristol, 2000. http://hdl.handle.net/1983/8efa1d22-0ff8-45a3-9a5c-bd5ea90e266f.
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The morphological and ecologicalevolution of middle-upper Eocene planktonic foraminiferal family Hantkeninidae is investigated in the context of the dramatic palaeoceanographic and climatic changes that marked the transition from Paleogene "greenhouse" to Neogene "icehouse" climatic conditions. Morphometric analysis proves that evolution in family Hantkeninidae was gradual but complex in detail with periods of relative stasis. Multiple lines of evidence demonstrate that Hantkenina evolved from planispiral clavate genus Clavigerinella and not, as was previously believed, from Pseudohastigerina micra. The ancestor of Clavigerinella was probably a low trochospiral form Paragloborotalia sp., which has been recognized for the first time in this study at a number of sites. Trends in chamber inflation, tubulospine angle and the position of the tubulospine on each chamber show the most dramatic evolutionary changes, indicating that these are the most useful characters for taxonomy. These morphological changes correlate well with known palaeoceanographic changes as well as the shift in hantkeninid ecology from a deep to a surface water habitat. Hantkeninids underwent pronounced adaptive evolution in depth habitats during the initial phase of the climatic transition. Lower middle Eocene forms lived in a cool deep-water environment within or below the oceanic thermocline and shifted to warmer surface waters in the late middle Eocene. They evolved in the low latitudes and were primarily. a tropical-subtropical group. The occurrence of Hantkenma australis at relatively high northerly and southerly latitudes during the middle Eocene may record a temporary expansion of warmer water conditions into these regions, possibly representing a hitherto unknown "hyperthermal" event. Clavigerinella is rare in middle Eocene open-ocean sequences but occasionally occurs in relative abundance in other localities (such as on continental margins and oceanic seamounts), suggesting that it was specialized for living in upwelling regions. A revised taxonomy of family Hantkeninidae is presented that reflects new understanding ofhantkeninid evolution. The reconstructed phylogeny demonstrates that the tubulospine-bearing genera Hantkenina and Cribrohantkenina represent a monophyletic clade. Multivariate analysis suggests that more than one morphological population existed at several times and that these may represent biological species. The results demonstrate that the hantkeninids are not merely passive recorders of ocean conditions but have instead evolved morphology and changed habitat in response to climate change.
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Eberwein, Astrid. "Holocene and Last Glacial Maximum (paleo-)productivity off Morroco : evidence from benthic foraminifera and stable carbon isotopes = (Paläo-)produktivität im Holozän und Letzten Glazialen Maximum vor Marokko erschlossen aus benthischen Foraminiferen und stabilen Kohlenstoffisotopen /." Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2007. http://www.loc.gov/catdir/toc/fy0712/2007425451.html.
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Mehrota, Nivedita. "Reconstruction of Holocene Paleoclimate Based on Benthic Foraminiferal Assemblages from Soledad Basin." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1310628185.
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Volkmann, Renate. "Planktic foraminifer ecology and stable isotope geochemistry in the Arctic Ocean : implications from water column and sediment surface studies for quantitative reconstructions of oceanic parameters = Ökologie planktischer Foraminiferen und stabile Isotope im Arktischen Ozean /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2000. http://www.gbv.de/dms/bs/toc/315939354.pdf.
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Allen, Kathryn. "Composition and structure of foraminiferal agglutinated test walls." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284673.
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Sexton, Philip. "Foraminiferal taphonomy, palaeoecology and palaeoceanography of the Eocene." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416473.
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Wade, Christopher Mark. "Analysis of HIV-1 and foraminiferal molecular evolution." Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/14622.
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In section A, five papers are presented which examine the evolution of HIV-1 both within and between patients. The first paper presented examines the molecular epidemiology of HIV-1 within Scotland, Northern England, and Ireland (paper I), with attention focused on identifying risk group associated differences within the cohort. This work also provides important background information for the interpretation of molecular data from transmission clusters. The main focus of the work on HIV-1 evolution has been on the transmission of HIV-1, with particular emphasis placed on mother-child transmission. Four papers are presented which examine evolutionary aspects of HIV-1 transmission. The first of these (paper II) examines the viral variants transmitted from mother to child in four mother-child transmission pairs. The second (paper III) analyses similar data from five mother-child transmission pairs, focusing predominantly on viral evolution within the child over the first year of life. The final two papers investigating HIV-1 transmission examine viral variation within two transmission sets. Paper IV examines the vertical transmission of HIV-1 to two infected children born to the same mother at an approximately two year interval, while paper V examines the heterosexual transmission of HIV-1 from a male index to two female contacts and the subsequent vertical transmission of HIV-1 to their two children. The phylogenetic placement of these transmission sets within the Edinburgh cohort is also assessed. In section B, four papers are presented which examine aspects of foraminiferal evolution. The first paper (paper I) focuses on the problems inherent in the amplification of foraminiferal DNA due to the association of large numbers of symbionts, commensals and food particles with each foraminifer. The amplification of foraminiferal sequences for the small subunit ribosomal RNA gene is then described, and the phylogenetic placement of the foraminifera within eukaryote evolution examined (papers II and III). Finally, the phylogenetic relationships within the foraminifera are described (paper V).
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Berberich, Doris. "Die planktische Foraminifere Neogloboquadrina pachyderma (Ehrenberg) im Weddellmeer, Antarktis = The planktonic foraminifere Neogloboquadrina pachyderma (Ehrenberg) in the Weddell Sea, Antarctica /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 1996. http://www.gbv.de/dms/bs/toc/194515826.pdf.
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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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Hudson, Wendy. "The evolution and palaeobiogeography of Mesozoic planktonic foraminifera." Thesis, University of Plymouth, 2007. http://hdl.handle.net/10026.1/719.
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In the 1960s Oberhauser and Fuchs (palaeontologists working at the Geologische Bundesanstalt in Vienna) described a range of new taxa from the Triassic of Austria that were thought to be the earliest planktonic foraminifera. The first reactions of the palaeontological community were negative but in the subsequent forty years our knowledge of Jurassic planktonic foraminifera has expanded considerably. A thorough re-evaluation of the Oberhauser and Fuchs collections in Vienna has shown that these species are probably not planktonic and that the first planktonic taxa appeared in the Toarcian. This origination in the centre of Western Tethys was followed by a rapid expansion of planktonic foraminifera throughout Peri-Tethys. This expansion is dominated by the genera Conoglobigerina and Globuligerina and while some believe that their separation is straightforward (based on apertural characters) analysis of large assemblages shows that this differentiation is not reliable and requires further analysis not only of holotypes, paratypes and topotypes but of large assemblages. In Southern Poland, Middle Jurassic limestones in the Pieniny Klippen Belt are described as foraminiferal packstones and represent the first evidence of a foraminiferal ooze on the ocean floor. This indicates that, by the mid-Jurassic, there was an oceanic stratification of the Aragonite and Carbonate Compensation Depths and that the modem ocean system had developed, although the depths of these various layers may have been different to those of the present day. By the Oxfordian a relatively diverse planktonic fauna had expanded throughout Peri- Tethys and, probably, around the globe in the tropics. The fauna expanded further in the early Cretaceous as Gondwana fragmented but data across the important Jurassic to Cretaceous transition is extremely limited and requires further investigation.
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Chapman, Mark Robert. "Late Pliocene planktonic foraminifera : palaeoceanography and faunal evolution." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332388.
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Khanna, Nikki. "The biological response of foraminifera to ocean acidification." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/8089.
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Elevated atmospheric concentrations of carbon dioxide (CO₂), partly driven by anthropogenic activity, are decreasing the pH of the oceans. This thesis aimed to assess the biological response of foraminifera to ocean acidification. Foraminifera are single-celled organisms that form the dominant component of many marine communities. A series of laboratory experiments were carried out on benthic intertidal foraminifera from the Eden and Ythan estuaries, NE Scotland, to assess the impacts of ocean acidification. The responses of two dominant intertidal species of foraminifera (Haynesina germanica and Elphidium williamsoni) to ocean acidification were initially investigated in a short-term (6 week) experiment. Multiple species and multiple stressors (seasonal temperature regime and elevated CO₂) were then incorporated in a long-term (18 month) mesocosm study to investigate the physiological consequences (e.g. survival, growth) of ocean acidification. Survival of both Haynesina germanica and Elphidium williamsoni was significantly reduced under low pH conditions. Live specimens of both these calcareous species were however recorded at low pH, in reduced numbers. Following long-term exposure to ocean acidification, foraminiferal populations were still dominated by calcareous forms. Agglutinated foraminifera were recorded throughout the long-term incubations but their numbers were not high enough in the initial sediment collections to allow them to contribute significantly to the populations. Overall, survival of all foraminifera was greatly reduced in elevated CO₂ treatments. Temperature effects were observed on foraminiferal survival and diversity with the largest CO₂ effects recorded under the seasonally varying temperature regime. Foraminiferal test damage for all live species was also highest under elevated CO₂ conditions. Test dissolution was particularly evident in Haynesina germanica with important morphological features, such as functional ornamentation, becoming reduced or completely absent under elevated CO₂ conditions. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness. In addition, changes in the relative abundance and activities of these important species could affect biological interactions (e.g. food web function) and habitat quality.
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Stouff, Véronique. "Interet des elevages de foraminiferes en laboratoire : etudes biologiques et ultrastructurales." Angers, 1998. http://www.theses.fr/1998ANGE0023.
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Apres un bref rappel sur le mode de vie et la biologie des foraminiferes, la methodologie des elevages est precisee, depuis la recolte jusqu'a la mise en place des specimens en incubateur. Les especes qui se sont le mieux adaptees aux conditions d'elevage (ammonia tepida, ammonia beccarii et elphidium crispum essentiellement) ont fait l'objet d'etudes biologiques et morphologiques en microscopie optique et en microscopie electronique a balayage (meb). Le suivi de la gametogenese a permis l'observation de gametes d'ammonia tepida et d'ammonia beccarii, et de zygotes d'ammonia beccarii. La schizogonie a ete etudiee en detail chez ammonia tepida, depuis la formation des proloculi dans le kyste de reproduction asexuee. Les consequences d'une hypersalinite sur le developpement ontogenique et l'induction de malformations ont ete mises en evidence chez ammonia tepida et chez elphidium crispum. Les consequences d'une decalcification, resultant du maintien des cultures en conditions acides, ont ete etudiees chez ammonia beccarii. L'interet de ces elevages pour l'etude morphologique et systematique de ces especes, ainsi que pour la reconnaissance de leur formes juveniles, a egalement ete demontre. Les applications possibles en ecologie et paleoecologie sont evoquees. La derniere partie de ce travail est consacree aux resultats obtenus en microscopie electronique a transmission (met), concernant les ultrastructures cellulaires d'ammonia tepida et d'ammonia beccarii. Une description detaillee des organites d'ammonia tepida est fournie. Quelques variations ultrastructurales importantes ont ete mises en relation avec l'etat physiologique et reproducteur des specimens. Certains organites rares ou absents chez ammonia tepida ont ete decrits chez ammonia beccarii, et une comparaison a ete effectuee entre les deux especes. Enfin, un cas tres particulier correspondant a un stade post-gametogenetique a pu etre observe et interprete chez ammonia beccarii, puis mis en relation avec les observations des gametes realisees en meb.
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Dos, Santos Francisco Kelmo Oliveira. "Ecological consequences of the 1997-98 El Niño Southern Oscillation on the major coral reef communities from northern Bahia, Brazil." Thesis, University of Plymouth, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246378.
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Speed, Craig Duncan. "High-resolution palaeoceanography of extreme early Pliocene carbonate-opal cycles in the eastern equatorial Pacific." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274423.
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Bordelon, Laura Anne. "AUSTRAL AUTUMN AND WINTER SEASONAL AFFECTS ON BENTHIC FORAMINIFERAL COMMUNITIES: BRANSFIELD AND NORTHERN GERLACHE STRAITS." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/150.
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The Southern Ocean has unique seasonal qualities due to the Antarctic Circumpolar Current (ACC) thermo-isolating the Antarctic continent. During summer months, surface primary productivity from algal blooms is very high. In the winter months, limited daylight hours (4 in winter) and formation of sea ice prevents sun light from reaching surface waters, therefore limiting productivity. The short seasons of productivity and long winters in Antarctica combined with seasonal changes in deep ocean temperatures, salinity, and fluxes of organic matter impact foraminiferal population dynamics. Fluctuations in surface primary productivity, as well as living foraminiferal assemblages have been documented around the Antarctica Peninsula, but the impact on benthic foraminiferal assemblages is poorly understood. This is a study of seasonal affects on benthic foraminiferal assemblages in the southern Bransfield-northern Gerlache Straits of the Southern Ocean. Surface sediment samples from 600 meters and 1200 meters water depth were collected during two seasonal cruises: early April to record the productivity of the end-of-summer bloom and late June to sample the less-productive winter period. Three hundred and sixty samples were collected from 7 sites and processed using standard techniques. To identify living foraminifera, samples were treated with Rose Bengal, and CellTracker Green on a select set of samples for comparison. Ninety total species were identified; seventy species from June and seventy-one from April, fifteen species of foraminifera unique to April, thirteen to June and two unique species in the CellTracker Green samples. The abundance of total living (stained tests) opportunistic benthic foraminiferal species from the 7 sampled sites show distinct temporal differences related to seasonality. An assemblage of deep water species was also found, as well as an assemblage of shallow water species. ANOVA and post hoc Tukey tests showed that the full cores must be analyzed to determine seasonal species assemblage changes. Cluster analysis and species abundances in CellTracker Green samples showed a marked difference from the Rose Bengal samples, consistent with literature that suggests the two methods differ. Fluctuating populations of foraminifera in fossil samples can be interpreted as changes in local or global climate. This study stands as a modern analog for fossil foraminiferal assemblages, and provides important information to help interpret paleoenvironmental conditions related to seasonality by defining seasonally and geographically distinct species assemblages.
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Demirel, Seda. "Foraminiferal Paleontology And Sequence Stratigraphy In The Upper Visean." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614831/index.pdf.
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The aim of this study is to investigate the Upper Visean substages, delineate the Visean - Serpukhovian boundary with calcareous foraminifera and interpret the foraminiferal evolution and sequence stratigraphical framework by using sedimentary cyclicity across the boundary section. For this purpose a 59,61 m thick stratigraphic section consisting of mainly limestone and partly sandstone and shale is measured in the Aziziye Gedigi and Oruçoglu Formations in the Pinarbasi Region of Eastern Taurides. A detailed micropaleontological study has revealed presence of important foraminiferal groups namely, parathuramminids, earlandiids, endothyroids, archaediscids, biseriamminids, fusulinids, loeblichids, tournayellids and paleotextularids and 145 species and three biozones. The biozones are, in ascending order, Eostaffella ikensis &ndash
Vissarionovella tujmasensis Zone (Mikhailovsky
Late Visean), Endothyranopsis cf. sphaerica &ndash
Biseriella parva Zone (Venevsky
Late Visean) and Eostaffella pseudostruvei &ndash
Archaediscids @ tenuis stage Zone (Taurssk
Early Serpukhovian). A detailed microfacies analysis was carried out in order to understand the depositional history and sedimentary cyclicity and construct the sequence stratigraphic framework of the studied area. Three main depositional environments consisting of open marine, shoal or bank and tidal flat environments were interpreted based on the analysis of 12 major microfacies and 11 sub-microfacies types. Based on the vertical association of microfacies twenty-six cycles, two sequence boundaries and three sequences were recognized in the studied section and these two sequence boundaries, which correspond to the Mikhailovsky and Venevsky horizons, are the records of the global sea level changes during the Late Paleozoic Ice Age. Within this context Visean &ndash
Serpukhovian boundary falls in the transgressive system tract of the third sequence. The duration of cycles are calculated as 117 ky and interpreted as orbitally induced glacioeustatic cycles.
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Laidler, Philip Damien. "Foraminiferal ecology of contemporary isolation basins in northwest Scotland." Thesis, Durham University, 2002. http://etheses.dur.ac.uk/4143/.
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Isolation basins contain high-resolution records of environmental change relating to RSL and climate since the last glacial maximum, and provide valuable data in constraining regional and global ice sheet and earth rheology models. A key weakness in current research is a lack of information regarding the identification of the reference tide level of different stages of basin isolation, and the role of factors such as freshwater input in controlling palaeosalinity. To address these issues, this thesis reports data collected from modern isolation basins from twenty sites in northwest Scotland. The basins range in size and elevation of their sill within the tidal cycle. Surface sediment samples were analysed for their foraminiferal composition, and other analyses of water chemistry and sedimentology were completed. Statistical analyses show a poor correlation between sill altitude and fauna. A transfer function was therefore produced based on average salinity, but calibration of this using fossil data was unsuccessful. This research demonstrates that the modern training set lacks adequate analogues for many of the fossil foraminiferal assemblages recorded in previous work. Likely causes for this include differences in the relative abundance of foraminiferal species between the modern and fossil data-sets, and the fact that no modern basin was found which has the water depth and salinity required for reconstruction of the fully marine stage. Because of these factors, foraminiferal data should be used with care in the definition of the indicative meaning of isolation basin sea-level index points. The statistical methods do, however, yield the first detailed understanding of the distributions of foraminifera in contemporary shallow water isolation basins, particularly with reference to their optimum and tolerance values for environmental variables. Variable salinity species such as Miliammina fusca are dominant in the training set, displaying their broad tolerance of environmental conditions.
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Leary, Paul Niell. "The Late Cenomanian anoxic event : implications for foraminiferal evolution." Thesis, University of Plymouth, 1987. http://hdl.handle.net/10026.1/2057.
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This study lnvestigates the effect of the late Cenomanian Oceanic Anoxic Event (OAE) on the planktonic and benthonic foraminifera. On the former, the OAE was the cause of major extinctions within the population, the return to pre-OAE oxygen levels permitting recolonization of the vacated niches. On the latter, the OAE caused extinctions but resulted in a low oxygen tolerant fauna which slowly evolved into the vacated niches on the post-oAE recovery of oxygen levels. The changes in the foraminiferal populations have been integrated With changes in other marine organisms through the late Cenomanian.
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Gfatter, Christian Helmut. "Application of Image Recognition Technology to Foraminiferal Assemblage Analyses." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7506.
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Analyses of foraminiferal assemblages involve time consuming microscopic assessment of sediment samples. Image recognition software, which systematically matches features within sample images against an image library, is widely used in contexts ranging from law enforcement to medical research. At present, scientific applications such as identification of specimens in plankton samples utilize flow through systems in which samples are suspended in liquid and pass through a beam of light where the images are captured using transmitted light. Identification of foraminifers generally utilizes reflected light, because most shells are relatively opaque.
My goal was to design and test a protocol to directly image foraminiferal specimens using reflected light and then apply recognition software to those images. A library of high quality digital images was established by photographing foraminifers identified conventionally from sediment samples from the west Florida shelf. Recognition software, VisualSpreadsheet™ by Fluid Imaging Technologies, Inc., was then trained to improve automated assemblage counts and those results were compared to results from direct visual assessment. The auto classification feature produced composite accuracies of foraminiferal groups in the range of 60–70% compared to traditional visual identification by a researcher using a stereo microscope. Site SC34, the source of images for the original image library, had an initial accuracy of 75% that was improved slightly through an alteration to one of the software classes, but composite accuracy plateaued at 60% with the updated filters. Thus, image acquisition advancements and further development of image recognition software will be required to improve automated or semi automated foraminiferal classifications. However, other potential applications were noted. For example, an advantage of acquiring digital images of entire samples or subsamples is the ability to collect quantitative data such as diameter and length, allowing size-frequency assessments of foraminiferal populations while possibly automating grain size analyses without requiring separate processing. In addition, data files of library and sample specimens can be readily shared with other researchers.
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Amirov, Elnur Fikret. "Planktonic Foraminiferal Biostratigraphy, Sequence Stratigraphy And Foraminiferal Response To Sedimentary Cyclicity In The Upper Cretaceous-paleocene Of The Haymana Basin (central Anatolia, Turkey)." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610140/index.pdf.
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The aim of this study is to establish the planktonic foraminiferal biozonation, to construct the sequence stratigraphical framework and to determine the foraminiferal response to sedimentary cyclicity in the sedimentary sequence spanning Upper Cretaceous-Paleocene in the Haymana basin (Central Anatolia, Turkey).
In order to achieve this study, the stratigraphic section was measured from sedimentary sequence of the Haymana, Beyobasi and YeSilyurt formations. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternating of siliciclastic and carbonate units.
On the account of the detailed taxonomic study of planktonic foraminifers, the biostratigraphic framework was established for the Maastrichtian-Paleocene interval. The biozonation includes 7 zonesPseudoguembelina hariaensis, P&
#945
, P1, P2, P3, P4 and P5 zones. The Cretaceous-Paleogene (K/P) boundary was delinated between the samples HEA-105 and 106. In order to construct the sequence-stratigraphical framework, the A, B, C and D-type meter-scale cycles were identified. Based on the stacking patterns of them, six depositional sequences, six third and two second order cycles were determined. Third order cycles coincide with the Global Sea Level Change Curve. On the account of the conducted petrographic analysis sandstone, mudstone, marl, limestone and muddy-limestone lithofacies were recorded in the studied samples. In order to demostrate the response of foraminifers to cyclicity, quantitative analysis has been carried out by counting the individuals of planktonic, benthonic foraminifers and ostracods. The best response to sedimentary cyclicity was revealed from planktonic foraminifers. The average abundance of planktonic foraminifers increases in the transgressive systems tract and decreases in the highstand systems tract.
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Vicedo, Vicedo Vicent. "Morfoestructura de los géneros cretácicos de los Rhapydioninidae (Foraminifera)." Doctoral thesis, Universitat Autònoma de Barcelona, 2008. http://hdl.handle.net/10803/3447.
Full textAbstract:
Los rapidionínidos representan un elemento importante, diverso y abundante en las comunidades de macroforaminíferos porcelanados de aguas poco profundas del Cretácico medio y superior. Su morfología general es muy similar, por lo que es necesario un estudio morfológico detallado para distinguir los géneros y especies en el interior de los diferentes grupos implicados. La revisión de los taxones aquí estudiados ha permitido eliminar ciertas contradicciones e inconsistencias que se han dado en la literatura del grupo, incrementar su potencial valor como fósiles guía y entender mejor el significado de su distribución paleogeográfica. En particular, el uso del nombre genérico de Pseudedomia Henson, 1948, (especie tipo P. multistriata, Maastrichtian) para designar especies del Ciclo de Maduración de la Comunidad (Global Community Maturation cycle, Hottinger 2001) previo, como "P." drorimensis Reiss et al., 1964, (Cenomaniense) o la supuesta sinonimia entre el género caribeño Raadshoovenia guatemalensis Van den Bold, 1946, (de edad supuestamente Paleoceno) y el género tetisiano Cuvillierinella salentina Papetti y Tedeschi, 1965, (Cretácico superior) han sido la causa de las dificultades en la comprensión de la evolución de la familia Rhapydioninidae en el tiempo y el espacio. Para llevar a cabo la revisión de los taxones, se han muestreado las localidades tipo o, cuando ha sido imposible, las localidades equivalentes siempre lo más cercanamente posible a las localidades tipo. En México, para el muestreo se han seguido las indicaciones y descripciones estratigráficas de Pêcheux (1984) y Michaud (1987). En España, se han considerado los trabajos de Martín-Chivelet (1993) para la Cordillera Bética y Calonge (1989) para la Cordillera Ibérica. En Grecia se han seguido los trabajos de Fleury (1974), mientras que el material de Italia fue recolectado por Mariano Parente en los Apeninos. Todos los rapidionínidos proceden de sedimentos extraordinariamente poco profundos. Por consiguiente, su restringido nicho ecológico dificulta una correlación precisa con la escala cronoestratigráfica en general y con la escala biostratigráfica basada en biozonaciones de orbitoídidos en particular. En consecuencia, algunas de las conclusiones taxonómicas dadas a nivel específico se deben considerar provisionales o tentativas. Los resultados de este trabajo confirman en gran medida las observaciones realizadas por Fleury y Fourcade en su trabajo de 1990, el único trabajo publicado en el que se da una visión general del grupo de los rapidionínidos desde que Henson publicara, en 1948, su monografía.
The rhapydioninids represent an important, diverse and abundant element in the shallow-water communities of porcelaneous foraminifera of the Middle and Late Cretaceous. Their general morphology is very similar and called for a careful morphological analysis in order to distinguish the genera and the species within the different groups involved. The revision of the relevant taxa given here permits to eliminate contradictions and inconsistencies in the current literature, to enhance their potential as biostratigraphic index fossils and to understand the significance of their paleogeographic distribution. In particular, the use of the generic name Pseudedomia Henson, 1948, (type species: P. multistriata, Maastrichtian) for species belonging to the previous Global Community Maturation cycle (Hottinger, 2001), such as "P." drorimensis Reiss et al., 1964, (Cenomanian) or the supposed synonymy of the Caribbean Raadshoovenia guatemalensis van den Bold, 1946, (said to be of Paleocene age) with the Tethyan Cuvillierinella salentina Papetti and Tedeschi, 1965, (Late Cretaceous) have produced considerable difficulties to understand the evolution of the rhapydioninid family in time and space.
In order to revise the various taxa involved, their type localities or as close equivalents as possible where sampled. In Mexico the stratigraphical descriptions and indications of Pêcheux (1984) and Michaud (1987) were followed. In Spain, we could relay on the work of Martin-Chivelet (1993) for the Betic Cordillera and of Calonge (1989) for the Iberian range. In Greece we founded our sampling on the papers of Fleury (1974), whereas in Italy Mario Parente collected suitable material for our research from the Apennines. All rhapydioninids are found in sediments with an extremely very shallow facies. Thus, their restricted ecological range often hampers a precise correlation with the chronostratigraphic time scale in general and with the ecologically closest biostratigraphic zonation based on orbitoids in particular. Therefore, some of the taxonomic conclusions on the species level must be considered as provisional or tentative. The results of the revisions given here confirm to a large extent the views expressed by Fleury and Fourcade in their paper of 1990, the only comprehensive overview on the group to be found in literature since Henson's monograph in 1948.
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Bryan, Sean Patrick. "Calibration of trace element paleoceanographic proxies in benthic foraminifera." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446083.
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Aze, Tracy. "Cope's rule and macroevolution of Cenozoic macroperforate planktonic foraminifera." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/22350/.
Full textAbstract:
Abstract A comprehensive phylogeny of macroperforate planktonic foraminifer species of the Cenozoic Era (~65 million years ago to present) is presented. The phylogeny is developed from a large body of palaeontological work that details the evolutionary relationships and stratigraphic (time) distributions of species-level taxa identified from morphology (‘morphospecies’). Morphospecies are assigned to morphogroups and ecogroups depending on test morphology and inferred habitat, respectively. Because gradual evolution is well documented in this clade, instances of morphospecies intergrading over time have been identified, allowing the elimination ‘pseudospeciation’ and ‘pseudoextinction’ from the record and thereby permit the construction of a more natural phylogeny based on inferred biological lineages. Each cladogenetic event is determined as either budding or bifurcating depending on the pattern of morphological change at the time of branching. This lineage phylogeny provides palaeontologically calibrated ages for each divergence that are entirely independent of molecular data. The tree provides a model system for macroevolutionary studies in the fossil record addressing questions of speciation, extinction, and rates and patterns of evolution. Specifically for this thesis the phylogenies provide a statistically robust framework for testing Cope’s rule (the evolutionary trend towards larger body size along a lineage). Eleven case studies were selected at random from all possible Neogene lineages and the mean areas of ancestor and descendant populations were compared. Over 6000 measurements were taken from 30 lineages and the resulting data show that Neogene macroperforate planktonic foraminifera do not support Cope’s rule with only 48% of the ancestor-descendant population comparisons demonstrating an increase in mean area. The size analysis illustrates that the most robust method for testing Cope’s rule is to compare ancestor-descendant populations from the beginning and end of evolutionary lineages as these are the least affected by temporal sampling biases.