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"The Island" Research Natural Area : a vegetation study with time and location comparisonsFox, M. Anne, 1939- 13 November 1995 (has links)
The purpose of this study was to document vegetation on "The Island", a
Research Natural Area at the confluence of the Crooked River and the Deschutes River in
central Oregon's Juniperus occidentalis Zone and to compare the results with an earlier
study reported in 1964 from 1960-'61 data. Present-day comparisons were also made
between "The Island" vegetation and three nearby sites. Percent cover and constancy of
major tree, shrub, grass, and forb species were considered along with percent cover of
litter, moss/lichen, rock and bare ground. Climatic data from the Metolius, OR Station
were examined, and the literature of succession especially succession in the juniper and
sagebrush steppe of the Great Basin was reviewed.
Data from 1992-'93 show more woody vegetation on "The Island", both tree and
shrub, than was measured thirty years ago. The only tree species present is Juniperus
occidentalis, while major shrub species are Artemisia tridentata and Purshia tridentata.
Grass cover appeared to be less, with a more even mix of the native perennial bunchgrass
species Agropyron spicatum, Festuca idahoensis, Poa sandbergii, and Stipa thurberiana,
than in the past when Agropyron spicatum and the alien annual grass, Bromus tectorum
dominated. The two plant associations identified in the 1964 report by Driscoll,
Juniperus occidentalis / Artemisia tridentata / Agropyron spicatum and Juniperus
occidentalis / Purshia tridentata / Agropyron spicatum were still identifiable, but the
shrub, Artemisia tridentata appeared to be entering areas where Purshia tridentata had
dominated in the past study. The present-day comparison sites showed many similarities
with sites on "The Island." The comparison sites in the Juniperus occidentalis / Artemisia
tridentata / Agropyron spicatum association measured slightly more tree and shrub cover
but similar grass cover when compared to "The Island." The comparison site in the
Juniperus occidentalis / Purshia tridentata / Agropyron spicatum association had more
tree cover and more Purshia tridentata cover, but less shrub cover generally and more
grass cover than the same association on "The Island." Forbs represented less than one
percent cover on all study sites. The differences recorded in 1992-'93 from that of the
study thirty years ago may reflect successional processes at work and a lack of any major
natural fires in the system. / Graduation date: 1996
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Structural fabric of the Palisades Monocline: a study of positive inversion, Grand Canyon, ArizonaOrofino, James Cory 29 August 2005 (has links)
A field study of positive inversion is conducted to describe associated structural
fabrics and to infer kinematic development of the Palisades Monocline, Grand Canyon,
Arizona. These features are then compared to sand, clay and solid rock models of
positive inversion to test model results and improve understanding of inversion
processes. The N40W 90 oriented Palisades fault underlying the monocline has
experienced northeast-southwest Precambrian extension and subsequent northeastsouthwest
Laramide contraction. The magnitude of inversion is estimated to be 25%
based on vertical offset across the fault, although this does not account for flexure or
horizontal shortening. The preferred N50W 90 joint and vein orientation and N50W 68
NE and SW conjugate normal faults are consistent with the Palisades fault and northeastsouthwest
extension. The N45E 90 joint orientation and approximately N40W 28 NE
and SW conjugate thrust faults are consistent with northeast-southwest contraction. The
deformation is characterized by three domains across the fault zone: 1) the hanging wall,
2) the footwall, and 3) an interior, fault-bounded zone between the hanging wall and
footwall. Extensional features are preserved and dominate the hanging wall,
contractional features define footwall deformation, and the interior, fault-bounded zone
is marked by the co-existence of extensional and contractional features. Extension
caused a master normal fault and hanging wall roll-over with distributed joints, veinsand normal faults. During inversion, contraction induced reverse reactivation of existing
hanging wall faults, footwall folding and footwall thrust-faulting. Precambrian normal
slip along the master normal fault and subsequent Laramide reverse slip along the new
footwall bounding fault created an uplifted domain of relatively oldest strata between the
hanging wall and footwall. Physical models of co-axial inversion suggest consistent
development of the three domains of deformation described at the Palisades fault,
however the models often require magnitudes of inversion greater than 50%. Although
vertical block motion during horizontal compression is not predicted directly by the
Mohr-Coulomb criterion, physical models and analytical solutions (incorporating Mohr-
Coulomb criterion) suggest maximum stress trajectories and near vertical failure above
high angle basement faults that compare favorably with the Palisades fault zone.
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GEOLOGIC CONTROLS ON PLIO-PLEISTOCENE DRAINAGE EVOLUTION OF THE KENTUCKY RIVER IN CENTRAL KENTUCKYAndrews Jr., William Morton 01 January 2004 (has links)
The primary goal of this project is to develop a relative chronology of events in the geologic history of the Kentucky River, and to consider the geologic controls on those events. This study utilized published geologic and topographic data, as well as field observations and extensive compilation and comparison of digital data, to examine the fluvial record preserved in the Kentucky River valley in central Kentucky. Numerous fluvial features including abandoned paleovalleys, fluvial terraces and deposits, bedrock benches, and relict spillways between adjacent river valleys were identified during the course of the study. The morphology of the modern valley coincides with bedrock lithology and can be used to describe the distribution and preservation of modern and ancient fluvial deposits and features in the study area. Bedrock lithology is the dominant control on valley morphology and on the distribution and preservation of fluvial deposits and features in the study area. Some stream trends are inherited from the late Paleozoic drainage of the Alleghanian orogeny. More recent inheritance of valley morphology has resulted from the erosion of the river from one lithology down into another lithology with differing erosional susceptibility, thus superposing the meander patterns of the overlying valley style onto the underlying lithology. One major drainage reorganization related to a pre-Illinoisan glacial advance disrupted the northward flow of the Old Kentucky River toward the Teays River system and led to organization of the early Ohio River. This greatly reduced the distance to baselevel, and led to abrupt incision and a change in erosional style for the Kentucky River. The successful projection of valley morphologies on the basis of bedrock stratigraphy, the history of erosion suggested by fission track data and the results of this study, as well as soil thickness and development, all argue against the existence of a midto late-Tertiary, low-relief, regional erosional surface. This study instead hypothesizes that the apparent accordance of ridge-top elevations in the study area is a reflection of a fluvially downwasted late Paleozoic depositional surface.
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Pensar e fazer geografia: uma contribuição para o controle de erosões em propriedades rurais no município de Regente Feijó/SP / Thinking and doing geography: a contribution to erosion control in rural properties in the municipality of Regente Feijó, São PauloSantana, Alessandro Donaire de [UNESP] 06 February 2017 (has links)
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Previous issue date: 2017-02-06 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Ao longo da história, as dinâmicas das sociedades provocaram a degradação acelerada dos recursos naturais, sendo as erosões um dos mais graves impactos materializados no espaço geográfico. No Brasil, as características de exploração geoeconômica, associadas às características pedoclimáticas, provocam o avanço das erosões. O Oeste Paulista apresenta alta suscetibilidade à ocorrência desses processos, em virtude da agropecuária praticada sobre solos com característica textural predominantemente arenosa. Por isso, a necessidade da adoção de estratégias que possibilitem a recuperação ou minimização das erosões. Neste sentido, esta pesquisa tem por objetivo principal analisar as transformações do espaço geográfico a partir do estudo das erosões presentes no noroeste do município de Regente Feijó/SP, viabilizando a implantação de técnica de controle de erosões em uma propriedade rural, possibilitando a articulação entre teoria e prática na minimização de seus impactos negativos no espaço rural. Para tanto, o trabalho foi realizado em parceria com um casal de agricultores familiares, cujos saberes contribuíram para a compreensão daquela realidade geográfica. Assim, a técnica, adaptada da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), consistiu na implementação de paliçadas feitas com materiais como bambus, madeiras e sacarias preenchidas com terra, posicionadas em sulcos e ravinas formados em um terraço rompido em área de pastagem. As paliçadas foram monitoradas por dezenove meses por meio da técnica das estacas graduadas (GUERRA, 2002). Também foram coletadas amostras dos sedimentos retidos a montante das paliçadas para realizar granulometria e fracionamento (EMBRAPA, 1997). Apesar do trânsito bovino na área, os resultados das estacas graduadas mostraram que as paliçadas retiveram considerável parcela de sedimentos durante as precipitações, além de permitir o desenvolvimento da gramínea Brachiaria decumbens, que funciona como uma barreira natural. A análise granulométrica dos sedimentos apontou mais de 80% de areia na sua composição, constituídas de areias finas e muito finas (entre 65% e 82% - fracionamento). Essas análises revelam a fragilidade dos solos da propriedade, dedicada à criação de gado de engorda, mas que tem um histórico de uso da terra marcado pela adoção de práticas agropecuárias inadequadas, o que provocou o avanço das erosões e, consequentemente, a adoção de estratégias de controle por parte dos agricultores: recomposição da mata ciliar dos córregos que perpassam a propriedade, bem como a recuperação de voçorocas e ravinas, deixando se recompor a vegetação. O avanço da pesquisa permitiu, ainda, desenvolver uma parceria com a Coordenadoria de Assistência Técnica Integral (CATi), que implementou um projeto para recuperar uma voçoroca na propriedade; esta foi aterrada e guarnecida a montante com bacias de contenção e terraços. Os agricultores cercaram a área para impedir o trânsito do gado e semearam a terra com sementes de gramíneas. Apesar da alteração da paisagem, os resultados preliminares mostraram que a intervenção foi adequada. Portanto, a Geografia pode contribuir para criar estratégias para enfrentar os mais diversos problemas ambientais. Porém, deve estar aberta ao “diálogo de saberes”, valorizando o saber popular que, em conjunção com o saber acadêmico, pode desenvolver ações que minimizem os impactos negativos causados pela humanidade na produção do espaço geográfico. / Throughout history, the dynamics of society have accelerated the degradation of natural resources, and erosions are one of the most serious impacts in geographic space. In Brazil, the characteristics of geo-economic exploration associated with pedoclimatic characteristics have led to the increase in erosion. The western region of São Paulo State has a high susceptibility to the occurrence of such processes due to agricultural practices being performed on soils with predominantly sandy textural characteristics. Therefore, there is a need to develop strategies enabling the recovery or minimization of erosion. The main objective of this research was to analyze geographic space transformations based on the investigation of erosions in the northwestern area of Regente Feijó, São Paulo. The application of erosion control techniques in a rural property allows articulation between theory and practice in minimizing their negative impacts on rural areas. The study was conducted in partnership with a couple of family farmers whose knowledge contributed to the understanding of geographical reality. The technique was based on the Brazilian Agricultural Research Corporation (EMBRAPA), and consisted of the implementation of palisades made with materials such as bamboos, woods, and bags filled with sand in furrows and ravines set up on a broken terrace in a pasture area. Palisades were monitored for 19 months using the graduated stakes technique reported by Guerra (2002). Samples were collected from sediments that were retained upstream of palisades to calculate granulometry and fractionation (EMBRAPA, 1997). Although there was cattle traffic in the area, results from graduated stakes showed that palisades retained a considerable amount of sediments during precipitation and allowed the development of the grass Brachiaria decumbens, which acts as a natural barrier. The granulometric analysis of sediments showed more than 80% of sand in its composition, containing fine and very fine sand (between 65% and 82%). These analyses revealed soil fragility, which has been used to raise cattle for fattening, with a history of land use marked by the adoption of inadequate agricultural practices. These characteristics led to erosion and, therefore, the adoption of control strategies by farmers: restoration of the ciliary forest of streams crossing the rural property and recovery of gullies and ravines, allowing the vegetation recovery. Advances in research have also enabled a partnership with the Coordination of Integral Technical Assistance (CATi), which implemented a project to recover a gully in the property that was grounded and trimmed upstream with containment basins and terraces. Farmers surrounded the area to stop cattle traffic and sowed the land with grass seeds. Despite landscape transformation, preliminary results showed that the intervention was adequate. Geography can help when it comes to creating strategies to face different environmental problems. However, it should be open to the “dialogue of knowledge”, respecting the common knowledge that together with academic knowledge, we can develop actions to minimize negative impacts caused by humans in the production of geographic space. / A lo largo de la historia, las dinámicas de las sociedades provocaron la degradación acelerada de los recursos naturales, siendo las erosiones uno de los más graves impactos materializados en el espacio geográfico. En Brasil, las características de explotación geoeconómica, asociadas a las características pedoclimáticas, provocan el avance de las erosiones. El oeste del Estado de São Paulo presenta una alta susceptibilidad a la ocurrencia de esos procesos, en virtud de la agropecuaria practicada sobre suelos con característica textural predominantemente arenosa. Por eso, hay la necesidad de la adopción de estrategias que posibiliten la recuperación o minimización de las erosiones. En este sentido, esta investigación tiene como objetivo principal analizar las transformaciones del espacio geográfico a partir del estudio de las erosiones presentes en el noroeste de la municipalidad de Regente Feijó, Estado de São Paulo, viabilizando la implantación de la técnica de control de erosiones en una propiedad rural, posibilitando la articulación entre teoría y práctica en la minimización de sus impactos negativos en el espacio rural. El trabajo se realizó en asociación con una pareja de agricultores familiares, cuyos conocimientos contribuyeron a la comprensión de esa realidad geográfica. Así, la técnica, adaptada de la Empresa Brasileña de Investigación Agropecuaria (EMBRAPA), consistió en la implementación de barreras hechas con materiales como bambú, maderas y sacos llenos de tierra, colocados en surcos y quebradas formados en una terraza rota en un área de pastoreo. Las barreras fueron monitoreadas durante diecinueve meses por medio de la técnica de las estacas graduadas (GUERRA, 2002). También se tomaron muestras de los sedimentos retenidos por encima de las barreras para realizar granulometría y fraccionamiento (EMBRAPA, 1997). A pesar del tránsito bovino en el área, los resultados de las estacas graduadas mostraron que las barreras conservaron considerable parte de los sedimentos durante las precipitaciones, además de permitir el desarrollo de la gramínea Brachiaria decumbens, que funciona como una barrera natural. El análisis granulométrico de los sedimentos dio como resultado más del 80% de arena en su composición, constituidas de arenas finas y muy finas (entre el 65% y el 82% - fraccionamiento). Estos análisis revelan la fragilidad de los suelos de la propiedad, dedicada a la creación de ganado de engorde, pero que tiene un historial de uso de la tierra que provocó el avance de las erosiones y, consecuentemente, la adopción de estrategias de control por parte de los agricultores: recomposición de la mata ciliar de los arroyos que atraviesan la propiedad y recuperación de quebradas, dejando que se recomponga la vegetación. La investigación permitió, además, desarrollar una alianza con la Coordinadora de Asistencia Técnica Integral (CATi), que implementó un proyecto para recuperar una quebrada en la propiedad; ésta fue puesta a tierra y arriba, para su protección, fueron construidas cuencas de contención y terrazas. Los agricultores rodearon el área para impedir el tránsito del ganado y sembraron la tierra con semillas de gramíneas. A pesar de la alteración del paisaje, los resultados preliminares mostraron que la intervención fue adecuada. Por lo tanto, la geografía puede contribuir a crear estrategias para enfrentar los más diversos problemas ambientales. Sin embargo, debe estar abierta al "diálogo de saberes", valorizando el saber popular que, en conjunción con el saber académico, puede desarrollar acciones que minimicen los impactos negativos causados en el espacio geográfico. / FAPESP: 2014/20850-1
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Les fortifications chez les Iroquoiens nordiques de 1400 à 1650 de notre èreDeschamps-Léger, Simon 08 1900 (has links)
Ce mémoire porte sur les fortifications des Iroquoiens nordiques de 1400 à 1650 de notre ère. Les Hurons, les Iroquois et les Iroquoiens du Saint-Laurent constituent les principaux groupes à l’étude. L’objectif initial consistait à comprendre l’absence de fortification sur certains sites de la région de Saint-Anicet et vérifier certaines informations ethnohistoriques suggérant que seulement les villages les plus imposants bénéficiaient d’une fortification. Notre étude, qui s’appuie sur 207 sites, confirme que les villages les plus imposants étaient plus souvent fortifiés, particulièrement chez les Hurons. Par contre, au niveau de l’Iroquoianie, on dénote la présence de fortifications sur des sites de taille modeste et leur absence sur certains sites de grande taille. On constate aussi chez les Hurons, les Iroquoiens du Saint-Laurent et les Iroquois que les sites frontaliers, à proximité des autres groupes, ont plus souvent fait l’objet de fortifications et ce peu importe leur taille. De plus, l’augmentation du nombre de sites fortifiés concorde, pour les trois groupes à l’étude, avec une augmentation des conflits intragroupes et intergroupes. Notre étude confirme aussi la relation étroite entre une sédentarité prolongée et la présence d’une palissade.
À partir des données compilées, nous avons également tenté d’observer dans quelle mesure évoluent les différentes caractéristiques physiques des fortifications (nombre de rangées, taille des pieux), les structures connexes (remblais/fossés, entrées, galeries, séparations internes) de même que l’influence européenne et les essences de bois employées. Encore une fois, l’augmentation de la taille des pieux et du nombre de rangées s’accordent avec une augmentation des conflits tandis que la présence de structures défensives connexes préhistoriques et l’utilisation de remblais et fossés chez les Iroquoiens du Saint-Laurent confirment une vocation défensive dès le XVe siècle.
Nous abordons en dernier lieu la valeur symbolique et d’intégration sociale des fortifications iroquoiennes. L’adéquation des données concernant l’évolution physique des palissades iroquoiennes ainsi que leur valeur symbolique et d’intégration sociale, somme toute limitée, confirme à notre avis la fonction défensive prévalante des fortifications iroquoiennes de 1400 à 1650 de notre ère. Nous reconnaissons toutefois les implications sociales et symboliques découlant des fortifications, dont la construction opportuniste était essentiellement communautaire et non-coercitive. / This thesis focuses on the study of the northern Iroquoians fortifications from 1400 to 1650 A.D. The Huron, Iroquois and Iroquoians of the St. Lawrence are the main groups under study. The initial objective was to understand the lack of fortification on Saint-Anicet site and to verify some ethnohistorical information suggesting that only the most imposing villages were fortified. Our study, based on 207 sites, confirms that the larger villages were more often fortified, particularly among the Hurons. However, at the Iroquoian level, we denote fortifications on small sites and their absence on some large sites. We also found that Huron, St. Lawrence Iroquoians and Iroquois border sites, near other groups, were more often fortified regardless of their size. In addition, the increase in the number of fortified sites for the three groups coincide with an increase in intra-group and inter-group conflicts. Our study also confirms the close relationship between a prolonged sedentary lifestyle and the presence of a palisade.
From the compiled data, we also observed the evolution of different physical characteristics of the fortifications (number of rows, pile size), related structures (embankment / ditch, entrances, galleries, internal separations), European influence and species of wood used for construction. Again, the increase in pile size and number of rows is consistent with an increase in conflict, while the presence of prehistoric related defensive structures and the use of embankments and ditches among the St. Lawrence Iroquoians confirm a defensive vocation from the XVe century.
Finally, we discuss the symbolic and social integration value of the Iroquoian fortifications. The adequacy of the data concerning the physical evolution of the Iroquoian palisades, as well as their limited symbolic and social integration value, confirms in our opinion the prevalent defensive function of the Iroquoian fortifications from 1400 to 1650 AD. We recognize, however, the social and symbolic implications of fortifications, whose opportunist construction was essentially communal and non-coercive.
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