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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Palaeoenvironment of Late Neogene Lacustrine Sediments at the Gray Fossil Site, Tennessee, USA

Worobiec, Elzbieta, Liu, Yu Sheng Christopher, Zavada, Michael S. 31 July 2013 (has links)
A new palaeopalynological investigation was conducted on 15 samples from four test-pits at the Gray Fossil Site (Bear Pit, Elephant Pit, Test Pit 2-2010, and Rhino Pit). In total, 50 morpho-species of miospores (including five species of spores, eight species of gymnosperm pollen, and 37 species of angiosperm pollen) and 18 morpho-species of freshwater algal micro-remains were identified. One new morphological species, related to zygospores of the Zygnemataceae, Stigmozygodites grayensis sp. nov., is proposed. The assemblage of fossil algae recovered provides insights into the palaeoenvironmental conditions of the uppermost (125 cm) part of the Gray Fossil Site sedimentary cover, deposited after the formation of a number of sinkholes, and the fill of the palaeosinkholes. Most of the algae identified prefer meso-to eutrophic conditions and are characteristic of stagnant to slowly flowing shallow fresh water. Therefore, the lacustrine fossiliferous sediments at the Gray Fossil Site represent pond deposits. The palaeopalynological analysis revealed differences in the composition of the miospore and algal assemblages of the pits studied, suggesting that the Test Pit 2-2010, Bear, and Elephant pits are similar and may have been formed in the same pond, while the presence of a higher percentage of algae in the Rhino Pit may indicate sedimentation in a separate water body.
2

Palaeoenvironment of Late Neogene Lacustrine Sediments at the Gray Fossil Site, Tennessee, USA

Worobiec, Elzbieta, Liu, Yu Sheng Christopher, Zavada, Michael S. 31 July 2013 (has links)
A new palaeopalynological investigation was conducted on 15 samples from four test-pits at the Gray Fossil Site (Bear Pit, Elephant Pit, Test Pit 2-2010, and Rhino Pit). In total, 50 morpho-species of miospores (including five species of spores, eight species of gymnosperm pollen, and 37 species of angiosperm pollen) and 18 morpho-species of freshwater algal micro-remains were identified. One new morphological species, related to zygospores of the Zygnemataceae, Stigmozygodites grayensis sp. nov., is proposed. The assemblage of fossil algae recovered provides insights into the palaeoenvironmental conditions of the uppermost (125 cm) part of the Gray Fossil Site sedimentary cover, deposited after the formation of a number of sinkholes, and the fill of the palaeosinkholes. Most of the algae identified prefer meso-to eutrophic conditions and are characteristic of stagnant to slowly flowing shallow fresh water. Therefore, the lacustrine fossiliferous sediments at the Gray Fossil Site represent pond deposits. The palaeopalynological analysis revealed differences in the composition of the miospore and algal assemblages of the pits studied, suggesting that the Test Pit 2-2010, Bear, and Elephant pits are similar and may have been formed in the same pond, while the presence of a higher percentage of algae in the Rhino Pit may indicate sedimentation in a separate water body.
3

Upper Cretaceous Palynomorphs from Coal Canyon, Coconino County, Arizona

Agasie, John M. January 1967 (has links)
The coal-bearing Dakota Sandstone at Coal Canyon, Arizona, which is located in the western portion of the Black Mesa basin, has yielded abundant, diverse, and generally well-preserved spores, pollen, and microplankton. The formation is characterized by high frequencies of fern spores, especially striate spores belonging to the Schizaeaceae, and angiospermous pollen consisting primarily of simple tricolpate and tricolporate grains. Gymnospermous pollen is comparatively uncommon. The microflora assemblage contains many exclusively Cretaceous species previously reported from Australia, western Europe, Siberia, and other localities of North America. A microflora which compares closely with the Dakota assemblage occurs in the Woodbine strata of Oklahoma. On the basis of palynologic evidence, the age of the Dakota Sandstone at Coal Canyon, is interpreted as lowermost Upper Cretaceous (Cenomanian).
4

Exploratory Palynology in the Sierra Nevada, California

Adam, David Peter January 1965 (has links)
Pollen analysis of two surface transects of modern soil samples and four stratigraphic sections from the central Sierra Nevada of California have provided a climatic record covering the time interval since the recession of the last glaciers of the Wisconsin glaciation. Two separate warm intervals are recognized between the recession of the Wisconsin glaciers and the reappearance of glaciers in the Sierra during the Little Ice Age.
5

Some Palynological Applications of Multivariate Statistics

Adam, David Peter January 1970 (has links)
Palynology involves the study of past climatic and environmental changes through changes in the relative frequencies of different pollen types through time. Several multivariate statistical methods are suggested which can help in the description of patterns within pollen data. These techniques are based on comparisons between samples. Samples were compared using the product-moment correlation coefficient computed from data which had been subjected to a centering transformation. The methods are described using a geometric model. If there are m samples and n pollen types, then the data can be regarded as a set of m points in an n-dimensional space. Cluster analysis produces a dendrograph or clustering tree in which samples are grouped with other samples on the basis of their similarity to each other. Principal component analysis produces a set of variates which are linear combinations of the pollen samples, are uncorrelated with each other, and do the best job of describing the data using a minimum number of dimensions. This method is useful in reducing the dimensionality of data sets. Varimax rotation acts on a subset of the principal components to make them easier to interpret. Discriminant analysis is used to find the best way to tell groups of samples apart, where the groups are known a priori. Once a means of discrimination among groups has been established using samples whose groups are known, unknown samples may be classified into the original groups. Canonical analysis produces a way to display the maximum separation between groups in a graphic manner. Examples of applications of these methods in palynology are shown using data from Osgood Swamp, California, and from southern Arizona. These methods offer the advantages of reproducibility of results and speed in pattern description. Once the patterns in the data have been described, however, their interpretation must be done by the palynologist.
6

Registro paleoambiental em cabeceira de drenagem inscrita no remanescente de superfície aplainada VIII (A.R.I.E. do Buriti - SW PR) / Paleoenvironmental records in head of drainage entered in the remaining at planed surface VIII (A.R.I.E. DO BURITI - SW PR)

Bertoldo, Edson 15 December 2010 (has links)
Made available in DSpace on 2017-07-10T17:31:07Z (GMT). No. of bitstreams: 1 Edson Bertoldo.pdf: 5608945 bytes, checksum: fd55c97dda4b7d20b2fa9438b702daf3 (MD5) Previous issue date: 2010-12-15 / This study identifies paleoenvironmental records in the remaining at planed surface VIII, in Pato Branco (SW PR), more precisely in conservation area (A.R.I.E. do Buriti) by analysis of palynomorphs in a bog, characterization of the surface formations and the 14C dating method. Throughout the testimony of 130 cm, 37 different taxa were identified, which were separated into five ecological categories (trees, shrubs, ground herbs, algae and fern spores). The dating estimated suggests that the base of the bog was formed approximately 13,700 years BP, a period related to the Last Glacial Maximum (LGM). At that time the head of drainage would not have a connection to the piped drainage waterway of Independence river, local base level. According to the data obtained, we can affirm that in the region of the study area during the transition from the Pleistocene / Holocene to the present, there are no records of savannah, only grassland areas in the Pleistocene, inferred by the presence of ground herbs, especially Borreria and Asteraceae found in 12,700 years BP 14C (estimated) and total absence of algae and pollen grains of tree species, suggesting drier hydrological regime. Occasionally, high precipitation phenomeno occurred on the slopes and promoted the degradation of soil horizons in the upper slope (nose), promoting the deposition of colluvial layers until the new water regime, wetter, allowing the establishment of a herbaceous vegetation accompanied by ferns, mainly in the lower areas. In about 10,600 years BP 14C (est.), maintenance of high humidity is established and high precipitation caused the water table surface in the hollow constantly accelerating the hidromorfization paleohorizonte A humic, and developing in the rainy seasons, a small pond in the central axis of the headboard. Fact evidenced by the presence of algae and a significant expansion of Araucaria angustifolia, which requires an annual rainfall exceeding 1,400 mm.yr-1, without a dry season. The predominant vegetation is replaced by the Araucaria Forest and Atlantic Rain Forest composed of genres trees, ground herbs and ferns. The maximum expansion of the Araucaria Forest is logged about 6,880 years BP 14C (est.), face the increase of all taxa recorded, mainly from Araucaria. The presence of algae was more pronounced, again suggesting the occurrence of a blade of water conserved by an abundant and regular rainfall. In the years that followed, probably to 1,060 years BP 14C (est.), a reduction of vegetation as a general rule, changing only in the present with the planting of araucaria after the creation of A.R.I.E. do Buriti. Sometime in this period, the hollow head of the drainage began to develop perennial drainage channels, allowing efficient drainage at the head of drainage, reducing moisture levels in the bog / O presente estudo identifica registros paleoambientais no remanescente de superfície aplainada VIII, no município de Pato Branco (SW PR), mais precisamente na Unidade de Conservação - A.R.I.E. do Buriti, através da análise de palinomorfos de uma turfeira, caracterização das formações superficiais e datação pelo método do 14C. Ao longo de um testemunho de 130 cm, foram identificados 37 táxons diferentes, os quais foram separados em cinco categorias ecológicas (árvores, arbustos, ervas terrestres, algas e esporos de pteridófitas). A datação estimada sugere que a base da turfeira formou-se à aproximadamente 13.700 anos A.P, período relacionado ao Último Máximo Glacial (UMG). Nessa época a cabeceira de drenagem não teria uma ligação canalizada com a rede de drenagem do rio Independência, nível de base local. De acordo com os dados obtidos, pode-se afirmar que na região da área de estudo, durante a passagem do Pleistoceno/Holoceno até o presente, não há registros de cerrado, apenas de áreas campestres no Pleistoceno, inferido pela presença de ervas terrestres, principalmente Asteraceae e Borreria encontrados em 12.700 anos A.P. (est.) e total ausência de algas e grãos de pólen de espécies arbóreas, sugerindo regime hidrológico mais seco. Eventualmente, fenômenos de alta precipitação ocorreram nas encostas e promoveram a degradação dos horizontes de solo na alta encosta (nose), promovendo a deposição de camadas coluviais até o novo regime hídrico, mais úmido, propiciando a instalação de uma vegetação herbácea acompanhada de pteridófitas, principalmente nas áreas mais baixas. Há cerca de 10.600 anos A.P. 14C (est.), a manutenção da elevação de umidade se estabelece e altos índices de precipitação fizeram com que o lençol freático aflorasse no hollow constantemente, acelerando a hidromorfização do paleohorizonte A húmico e desenvolvendo, nas estações chuvosas, uma pequena lagoa no eixo central da cabeceira. Fato evidenciado pela presença de algas e por uma expansão significativa de Araucaria angustifolia, a qual necessita de um regime pluviométrico superior a 1.400 mm.ano-1, sem estação seca definida. A vegetação predominante passa a ser de Floresta Ombrófila Mista e Floresta Pluvial Atlântica composta por gêneros arbóreos, ervas terrestres e pteridófitas. A máxima expansão da Floresta Ombrófila Mista é registrada a cerca de 6.880 anos A.P. (est.), face o aumento de todos os táxons registrados, principalmente Araucaria. A presença de algas ficou mais acentuada, sugerindo novamente a ocorrência de uma lâmina de água, conservada por um regime pluviométrico abundante e regular. Nos anos que se seguiram, provavelmente à 1.060 anos A.P. (est.), ocorreu uma redução da vegetação de modo generalizado, modificando-se apenas no presente com o plantio de araucárias após a criação da A.R.I.E. do Buriti. Em algum momento desse período o hollow da cabeceira de drenagem passou a desenvolver canais de drenagem perenes, que permitiram a drenagem eficiente na cabeceira, diminuindo os níveis de umidade da turfeira
7

Registro paleoambiental em cabeceira de drenagem inscrita no remanescente de superfície aplainada VIII (A.R.I.E. do Buriti - SW PR). / Paleoenvironmental records in head of drainage entered in the remaining at planed surface VIII (A.R.I.E. DO BURITI - SW PR)

Bertoldo, Edson 15 December 2010 (has links)
Made available in DSpace on 2017-05-12T14:42:39Z (GMT). No. of bitstreams: 1 Edson Bertoldo.pdf: 5608945 bytes, checksum: fd55c97dda4b7d20b2fa9438b702daf3 (MD5) Previous issue date: 2010-12-15 / This study identifies paleoenvironmental records in the remaining at planed surface VIII, in Pato Branco (SW PR), more precisely in conservation area (A.R.I.E. do Buriti) by analysis of palynomorphs in a bog, characterization of the surface formations and the 14C dating method. Throughout the testimony of 130 cm, 37 different taxa were identified, which were separated into five ecological categories (trees, shrubs, ground herbs, algae and fern spores). The dating estimated suggests that the base of the bog was formed approximately 13,700 years BP, a period related to the Last Glacial Maximum (LGM). At that time the head of drainage would not have a connection to the piped drainage waterway of Independence river, local base level. According to the data obtained, we can affirm that in the region of the study area during the transition from the Pleistocene / Holocene to the present, there are no records of savannah, only grassland areas in the Pleistocene, inferred by the presence of ground herbs, especially Borreria and Asteraceae found in 12,700 years BP 14C (estimated) and total absence of algae and pollen grains of tree species, suggesting drier hydrological regime. Occasionally, high precipitation phenomeno occurred on the slopes and promoted the degradation of soil horizons in the upper slope (nose), promoting the deposition of colluvial layers until the new water regime, wetter, allowing the establishment of a herbaceous vegetation accompanied by ferns, mainly in the lower areas. In about 10,600 years BP 14C (est.), maintenance of high humidity is established and high precipitation caused the water table surface in the hollow constantly accelerating the hidromorfization paleohorizonte A humic, and developing in the rainy seasons, a small pond in the central axis of the headboard. Fact evidenced by the presence of algae and a significant expansion of Araucaria angustifolia, which requires an annual rainfall exceeding 1,400 mm.yr-1, without a dry season. The predominant vegetation is replaced by the Araucaria Forest and Atlantic Rain Forest composed of genres trees, ground herbs and ferns. The maximum expansion of the Araucaria Forest is logged about 6,880 years BP 14C (est.), face the increase of all taxa recorded, mainly from Araucaria. The presence of algae was more pronounced, again suggesting the occurrence of a blade of water conserved by an abundant and regular rainfall. In the years that followed, probably to 1,060 years BP 14C (est.), a reduction of vegetation as a general rule, changing only in the present with the planting of araucaria after the creation of A.R.I.E. do Buriti. Sometime in this period, the hollow head of the drainage began to develop perennial drainage channels, allowing efficient drainage at the head of drainage, reducing moisture levels in the bog / O presente estudo identifica registros paleoambientais no remanescente de superfície aplainada VIII, no município de Pato Branco (SW PR), mais precisamente na Unidade de Conservação - A.R.I.E. do Buriti, através da análise de palinomorfos de uma turfeira, caracterização das formações superficiais e datação pelo método do 14C. Ao longo de um testemunho de 130 cm, foram identificados 37 táxons diferentes, os quais foram separados em cinco categorias ecológicas (árvores, arbustos, ervas terrestres, algas e esporos de pteridófitas). A datação estimada sugere que a base da turfeira formou-se à aproximadamente 13.700 anos A.P, período relacionado ao Último Máximo Glacial (UMG). Nessa época a cabeceira de drenagem não teria uma ligação canalizada com a rede de drenagem do rio Independência, nível de base local. De acordo com os dados obtidos, pode-se afirmar que na região da área de estudo, durante a passagem do Pleistoceno/Holoceno até o presente, não há registros de cerrado, apenas de áreas campestres no Pleistoceno, inferido pela presença de ervas terrestres, principalmente Asteraceae e Borreria encontrados em 12.700 anos A.P. (est.) e total ausência de algas e grãos de pólen de espécies arbóreas, sugerindo regime hidrológico mais seco. Eventualmente, fenômenos de alta precipitação ocorreram nas encostas e promoveram a degradação dos horizontes de solo na alta encosta (nose), promovendo a deposição de camadas coluviais até o novo regime hídrico, mais úmido, propiciando a instalação de uma vegetação herbácea acompanhada de pteridófitas, principalmente nas áreas mais baixas. Há cerca de 10.600 anos A.P. 14C (est.), a manutenção da elevação de umidade se estabelece e altos índices de precipitação fizeram com que o lençol freático aflorasse no hollow constantemente, acelerando a hidromorfização do paleohorizonte A húmico e desenvolvendo, nas estações chuvosas, uma pequena lagoa no eixo central da cabeceira. Fato evidenciado pela presença de algas e por uma expansão significativa de Araucaria angustifolia, a qual necessita de um regime pluviométrico superior a 1.400 mm.ano-1, sem estação seca definida. A vegetação predominante passa a ser de Floresta Ombrófila Mista e Floresta Pluvial Atlântica composta por gêneros arbóreos, ervas terrestres e pteridófitas. A máxima expansão da Floresta Ombrófila Mista é registrada a cerca de 6.880 anos A.P. (est.), face o aumento de todos os táxons registrados, principalmente Araucaria. A presença de algas ficou mais acentuada, sugerindo novamente a ocorrência de uma lâmina de água, conservada por um regime pluviométrico abundante e regular. Nos anos que se seguiram, provavelmente à 1.060 anos A.P. (est.), ocorreu uma redução da vegetação de modo generalizado, modificando-se apenas no presente com o plantio de araucárias após a criação da A.R.I.E. do Buriti. Em algum momento desse período o hollow da cabeceira de drenagem passou a desenvolver canais de drenagem perenes, que permitiram a drenagem eficiente na cabeceira, diminuindo os níveis de umidade da turfeira
8

Apports des microfossiles non-polliniques à l'histoire du pastoralisme sur le versant nord Pyrénéen : entre référentiels actuels et reconstitution du passé / The use of non-pollen palynomorphs for reconstructing the history of pastoral activities in the Pyrenees : from modern datasets to reconstruction of the past

Cugny, Carole 27 September 2011 (has links)
Les microfossiles non-polliniques, des restes de divers organismes préservés dans les sédiments lacustres ou tourbeux, sont de plus en plus couramment employés en paléoécologie. Parmi ces microrestes, les spores de champignons coprophiles sont privilégiées dans les reconstructions des activités humaines telles que les activités pastorales. L’aptitude de ces spores à refléter la présence ou l’abondance des troupeaux n’est pas encore complètement comprise. Des analogues modernes ont été collectés dans deux zones d’estive, dans les montagnes du Pays Basque et d’Ossau. Des analyses de gradients contraintes par des variables environnementales ont permis d’identifier des assemblages non-polliniques associés à diverses conditions environnementales en contexte humide et terrestre. Un cortège d’ascospores de groupes coprophiles liées aux activités pastorales a pu être isolé. Les référentiels ont également fourni des informations sur la portée spatiale de l’information non-pollinique.Les microfossiles non-polliniques ont été étudiés dans quatre séquences tourbeuses en complément d’autres sources d’informations paléoenvironnementales (pollen, signal incendie). Ils ont fourni les informations sur les dynamiques des quatre sites durant l’Holocène et les périodes historiques. Les résultats des référentiels sont appliqués à l’interprétation des dynamiques pastorales. Les résultats modernes et fossiles montrent que la charge pastorale n’est pas le seul paramètre qui influence les signaux coprophiles ; ces spores pourraient avoir un potentiel d’indicateurs paléoenvironnementaux et pastoraux plus étendu qu’attendu.Les ascospores de groupes coprophiles sont décrites et illustrées ainsi que d’autres microfossiles fongiques, algaux et indéterminés. / Non-pollen palynomorphs, microscopic remains produced by a variety of organisms and preserved in peat and lake sediments, are now more widely used in palaeoenvironmental studies. In particular, spores of coprophilous fungi are considered as an adapted tool to reconstruct past land-use such as pastoral activities. However, their ability to reflect the presence and/or the number of cattle is not fully understood yet. Modern analogs from summer pastures in the Basque Mountains and the Ossau valley have been collected. Numerical analysis of modern non pollen-palynomorphs and environmental variables helped to distinguish several pools of microremains associated to distinct environmental conditions in both terrestrial and wet ecosystems. A group of ascospores of dung-related fungi clearly related to grazing activities was isolated. The modern dataset also provided useful information on the spatial scale represented by non-pollen palynomorphs. Fossil non-pollen palynomorphs from four peat records, combined with other palaeoenvironmental data (pollen, fire frequencies), have been studied. They informed on the evolution of the local conditions of the wetlands during Holocene and historical times. The modern data set is used to aid interpretation of the dynamics of past land-use and pastoral activities. The results from both modern and fossil approaches show that other parameters than the grazing pressure can induce variability in the copropilous signals; the indicative value of dung-related ascospores might be broader than expected. The ascospores of dung-related taxa are described and illustrated, alongside with other fungal, algal and unidentified microremains.
9

Late Quaternary Vegetation History And Climate Change In The Gobi Desert, South Mongolia / Spätquartäre Vegetationsgeschichte und Klimaveränderungen in der Wüste Gobi, südliche Mongolei

Murad, Waheed 28 June 2011 (has links)
No description available.
10

Vegetation, climate and environmental dynamics of the Black Sea/Northern Anatolian region during the last 134 ka obtained from palynological analysis

Shumilovskikh, Lyudmila 06 March 2013 (has links)
No description available.

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