No description available.

Thèse (M.Sc.)--Université Laval, 2005. / Titre de l'écran-titre (visionné le 28 septembre 2005). Bibliogr.

Across Britain, there are over 100 possible early-medieval linear earthworks commonly termed dykes; in total, they stretch for over 400 kilometres. They vary in size from those just 100 metres in length to the famous Offa’s Dyke, which is over 95 kilometres long. There have been studies of individual dykes (Noble and Gelling 1983 for example) and general discussions of the larger examples (Squatriti 2002 for example), but no systematic attempt to catalogue and analyse them all. Their size and number suggests these earthworks were probably an important aspect of early-medieval life and have the capacity to tell us a great deal about the societies that built them. Dating such earthworks is difficult even with modern archaeological techniques and, as few early-medieval written sources survive, historians have often incorrectly ascribed enigmatic dykes to this period. This present study ascertained which dykes probably belong to the early-medieval period and contains a comprehensive gazetteer of them in the appendix. It also discusses how the dykes relate to the surviving written records, how many people were involved in their construction, what were their functions and what dykes can tell us about the processes that created early-medieval Britain. It calculated that far fewer people were needed to build them than many previous studies had supposed. While some were estate boundaries and King Offa may have ordered the building of the dyke that bears his name to bolster his power, it is argued that many of these earthworks were designed to prevent raiding. The dykes were a symptom of the endemic low-intensity warfare and small-scale forays into neighbouring territories that often characterised this period.

A study f the characters of the Tertiary dyke-swarms of Skye, Ardnmurchan and. the Small Isles of Invernessshire is based on observations at over 7500 dyke-outcrops, most of whiciL are located along well-exposed traverses. Because of geological limitations analyses of the properties of the dykes (trend, dip and thickness) can be semi-statistical only. Each of the dyke-swarms consists of a regional linear component of LW. to N.N.W. trending dykes, including parallel secondary-swarms in Skye and Ardnamurchan, together with in Skye and R.hum N.E. subswarnis of distinctive geo-. graphic distribution and comparatively- low intensities. The observations taken have facilitated: (a.) the construction of contour-maps depicting symmetrical distributions of multiple- dykes, of the arithmetic-average trends and thicknesses of the dykes, etc., (b.) both an approximate delimitation of regional-swarms and the distinction of these from subsidiary-avarms, in each case on the basis of the intensity- distribution and trend-distribution of the constituent dykes, and Cc.) the discovery of a latent plutonic -complex near Jluck, az a possible "centre" off the rwrth-west coast of Lewis. The trends, thicknesses, and to some extent the dips of small groups of dykes are intimately related to: (i.) the locations of those dykes with respect to the axes of highintensity of both crustal-stretch (dilation) and number of dykes per kilometre, (ii.) the positions of the dykes in relation to the site of the roughly contemporaneous Central Intrusive Coiiplexes, and (iii.) the structure of the country-- rock in which the dykes were emplaced, especially in the cases of the !oinian rocks, the Tertiary lavas, and the peripherally folded Mesozoic rocks bordering the Central Complex of Skye. The form and structure of the dyke-swarms, the distribution of the petrological types of dykes, and the available aeromagnetic, gravity-anomaly, and radiometric-dating evidence, indicate that the emplacement of each dyke-swarm is related to a sone of N.W. transcurrent faulting roughly paralleling the major dilation-axis of the swarm. Such faults were the consequence of differential movement of crustal blocks away from the line of a proposed Tertiary separation (Rockall Trough) of the British mainland and Rockall Plateau. Intracrustal, elongate, ridge-like basaltic magma-reservirs, whose ultimate source was the upper mantle, are believed to have ascended each of these faults. At the intersections of the N.W. transcurrent faults with preexisting N.E. faults cylinders of basaltic magma arose to form the Central Intrusive Complexes. Dyke-swarms developed as offshoots of the basaltic ridges and to a small extent from the basaltic cylinders, under the influence of a N.E. to S.W. tension resulting from a relative separation in this same direction of' the crustal blocks on both sides of the Rockall Trough rift.

Thesis (M.Sc.)--Memorial University of Newfoundland, 1995. / Typescript. Bibliography: leaves 69-73. Also available online.

Esta tese apresenta os resultados dos estudos petrográficos, geoquímicos e de química mineral dos enxames de diques ácidos e básicos e suas encaixantes graníticas associadas ao Batólito Pelotas nas regiões de Piratini e Pinheiro Machado, RS. Os dados obtidos apontam para a existência de dois tipos de diques contemporâneos, ácidos e básicos, gerados aparentemente por processos e fontes magmáticas distintas, com os primeiros sendo associados ao magmatismo da fase final (Granitos da Suíte Dom Feliciano) do Batólito Pelotas, desenvolvido já em regime tectônico extensional. Os diques básicos, apesar da composição distinta, mostram evidências de campo e petrográficas da existência de mistura de magmas, sugerindo contemporaneidade com os diques ácidos. A biotita é o principal mineral máfico dos diques ácidos, enquanto o piroxênio ao lado do plagioclásio mais cálcico (conteúdos mais elevados em moléculas de anortita) aparece associado aos diques básicos, sugerindo que o magmatismo de cada dique foi gerado em condições termodinâmicas e níveis crustais bastante diferentes. Os aspectos de campo e as texturas observadas nos granitos encaixantes mostram a existência da superposição de deformação no estado sólido, tanto em condições dúcteis quanto em condições rúpteis, deformações estas que não foram observadas nos diques. Contudo, as texturas observadas nos diques (micrográfica, mirmequítica, dentre outras) sugerem a presença de líquido residuais ricos em sílica interagindo com minerais de mais alta temperatura já cristalizados. Os dados geoquímicos caracterizam para a região de Piratini diques de composição riolito, traquito e basalto, enquanto para a região de Pinheiro Machado caracterizam diques de composição riolito, traquidacito, dacito, latito e basalto. O mg# revela que os diques ácidos da região de Piratini são mais evoluídos do que as demais rochas estudadas. Os riolitos e traquitos de Piratini têm características de um magmatismo alcalino, e os basaltos, de magmatismo transicional com afinidade alcalina. Os riolitos, dacitos, latitos e traquidacitos de Pinheiro Machado caracterizam-se como magmatismo cálcio alcalino alto-K e, moderadamente alcalino, com o basalto mostrando-se cálcio alcalino. Os diques ácidos de ambas as regiões estudadas representam um conjunto relativamente homogêneo com relação aos conteúdos dos elementos terras raras, e mostram conteúdos mais acentuados em ETR leves, anomalias fortemente negativas de Eu e valores baixos de ETR pesados, sugerindo fracionamento pelo feldspato alcalino. Os diagramas multi-elementares mostram padrão similar entre os diques ácidos e os granitos, com anomalias negativas em Ba, Sr, Eu, Ti, Sc e Ni, enriquecimento em relação ao condrito em K, Rb, Zr, Y e Tb, enquanto o padrão dos diques básicos apresenta anomalias positivas em Ba, Ti, Sr, Eu e La, sendo levemente enriquecidos em relação ao condrito em K, Nd e Zr. A anomalia positiva em Eu pode ser explicada pela presença de anfibólio. A provável correlação dos diques ácidos com as suítes graníticas mais jovens do Batólito Pelotas sugere tratar-se de um magmatismo com características tectônicas tardi-a póscolisionais ao ciclo brasiliano. / New petrographic, geochemistry and mineral chemistry data from acid and basic dyke swarms, associated to the Pelotas Batholith in the Piratini, Pinheiro Machado regions, within the Rio Grande do Sul state are presented in this work. The obtained data suggest that the two types of dykes were generated by different magmatic sources and processes, within an extensional setting that was linked to the Pelotas Batholith. These data suggest also an affinity between the acid dykes and granites from the Dom Feliciano Suite. The basic dykes show different compositions. Field and petrographic evidences shown the existence of magma mixing, suggesting contemporaneity with the acid magmatism. Biotite is the mafic mineral of the acid rocks, whereas pyroxene and calcic plagioclase are the minerals of the basic rocks and together suggest that the magmatism was formed within different thermodynamic and crustal level situations. Field and structural characteristic of the host granitoids show solid-state superimposed deformations within ductile and ruptil regimes, a situation that was not seen in the dykes. Some dykes shown textures mirmekite and graphic suggesting the presence of residual liquid in contact with already crystallized higher temperature minerals. Geochemical data shown that the Piratini dikes are ryholites, trachites, and basalts, whereas of the Pinheiro Machado are ryholites, trachyandesites, dacites, lathites and basalts. Mg# suggest that Piratini acid dikes are more evolved than the other rocks. Ryholites and trachites from Piratini have alkaline to transitional characteristics. Ryholites, dacites, lathites and trachyandesites from Pinheiro Machado are high-k calc-alkaline to moderately alkaline, with the basaltic types showing calc-alkaline nature. The acid dykes of both regions up present one group of rocks relatively homogeneous with relation the rare earth element (REE) values, showing values more pronounced in light RRE, largely negative Eu anomalies and values low in heavy REE, suggesting fractionation of alkaline feldspar. Multielementary diagrams of the studied rocks shown similar pattern between the acid dykes and granites, with negative anomalies in Ba, Sr, Eu, Ti, Sc and Ni, and enrichement in relation to the chondrite in K, Rb, Zr, Y and Tb, whereas the basic dykes pattern shown positive anomalies in Ba, Ti, Sr, Eu and La, being lightly enriched in K, Nd and Zr. Positive Eu anomalies may be interpreted by presence of amphibole. The probable correlation of acid dykes with newer granitic suites of the Pelotas Batholith suggests magmatism with tectonic characteristics late and post-collisionals the Brasiliano Cycle.

Esta tese apresenta os resultados dos estudos petrográficos, geoquímicos e de química mineral dos enxames de diques ácidos e básicos e suas encaixantes graníticas associadas ao Batólito Pelotas nas regiões de Piratini e Pinheiro Machado, RS. Os dados obtidos apontam para a existência de dois tipos de diques contemporâneos, ácidos e básicos, gerados aparentemente por processos e fontes magmáticas distintas, com os primeiros sendo associados ao magmatismo da fase final (Granitos da Suíte Dom Feliciano) do Batólito Pelotas, desenvolvido já em regime tectônico extensional. Os diques básicos, apesar da composição distinta, mostram evidências de campo e petrográficas da existência de mistura de magmas, sugerindo contemporaneidade com os diques ácidos. A biotita é o principal mineral máfico dos diques ácidos, enquanto o piroxênio ao lado do plagioclásio mais cálcico (conteúdos mais elevados em moléculas de anortita) aparece associado aos diques básicos, sugerindo que o magmatismo de cada dique foi gerado em condições termodinâmicas e níveis crustais bastante diferentes. Os aspectos de campo e as texturas observadas nos granitos encaixantes mostram a existência da superposição de deformação no estado sólido, tanto em condições dúcteis quanto em condições rúpteis, deformações estas que não foram observadas nos diques. Contudo, as texturas observadas nos diques (micrográfica, mirmequítica, dentre outras) sugerem a presença de líquido residuais ricos em sílica interagindo com minerais de mais alta temperatura já cristalizados. Os dados geoquímicos caracterizam para a região de Piratini diques de composição riolito, traquito e basalto, enquanto para a região de Pinheiro Machado caracterizam diques de composição riolito, traquidacito, dacito, latito e basalto. O mg# revela que os diques ácidos da região de Piratini são mais evoluídos do que as demais rochas estudadas. Os riolitos e traquitos de Piratini têm características de um magmatismo alcalino, e os basaltos, de magmatismo transicional com afinidade alcalina. Os riolitos, dacitos, latitos e traquidacitos de Pinheiro Machado caracterizam-se como magmatismo cálcio alcalino alto-K e, moderadamente alcalino, com o basalto mostrando-se cálcio alcalino. Os diques ácidos de ambas as regiões estudadas representam um conjunto relativamente homogêneo com relação aos conteúdos dos elementos terras raras, e mostram conteúdos mais acentuados em ETR leves, anomalias fortemente negativas de Eu e valores baixos de ETR pesados, sugerindo fracionamento pelo feldspato alcalino. Os diagramas multi-elementares mostram padrão similar entre os diques ácidos e os granitos, com anomalias negativas em Ba, Sr, Eu, Ti, Sc e Ni, enriquecimento em relação ao condrito em K, Rb, Zr, Y e Tb, enquanto o padrão dos diques básicos apresenta anomalias positivas em Ba, Ti, Sr, Eu e La, sendo levemente enriquecidos em relação ao condrito em K, Nd e Zr. A anomalia positiva em Eu pode ser explicada pela presença de anfibólio. A provável correlação dos diques ácidos com as suítes graníticas mais jovens do Batólito Pelotas sugere tratar-se de um magmatismo com características tectônicas tardi-a póscolisionais ao ciclo brasiliano. / New petrographic, geochemistry and mineral chemistry data from acid and basic dyke swarms, associated to the Pelotas Batholith in the Piratini, Pinheiro Machado regions, within the Rio Grande do Sul state are presented in this work. The obtained data suggest that the two types of dykes were generated by different magmatic sources and processes, within an extensional setting that was linked to the Pelotas Batholith. These data suggest also an affinity between the acid dykes and granites from the Dom Feliciano Suite. The basic dykes show different compositions. Field and petrographic evidences shown the existence of magma mixing, suggesting contemporaneity with the acid magmatism. Biotite is the mafic mineral of the acid rocks, whereas pyroxene and calcic plagioclase are the minerals of the basic rocks and together suggest that the magmatism was formed within different thermodynamic and crustal level situations. Field and structural characteristic of the host granitoids show solid-state superimposed deformations within ductile and ruptil regimes, a situation that was not seen in the dykes. Some dykes shown textures mirmekite and graphic suggesting the presence of residual liquid in contact with already crystallized higher temperature minerals. Geochemical data shown that the Piratini dikes are ryholites, trachites, and basalts, whereas of the Pinheiro Machado are ryholites, trachyandesites, dacites, lathites and basalts. Mg# suggest that Piratini acid dikes are more evolved than the other rocks. Ryholites and trachites from Piratini have alkaline to transitional characteristics. Ryholites, dacites, lathites and trachyandesites from Pinheiro Machado are high-k calc-alkaline to moderately alkaline, with the basaltic types showing calc-alkaline nature. The acid dykes of both regions up present one group of rocks relatively homogeneous with relation the rare earth element (REE) values, showing values more pronounced in light RRE, largely negative Eu anomalies and values low in heavy REE, suggesting fractionation of alkaline feldspar. Multielementary diagrams of the studied rocks shown similar pattern between the acid dykes and granites, with negative anomalies in Ba, Sr, Eu, Ti, Sc and Ni, and enrichement in relation to the chondrite in K, Rb, Zr, Y and Tb, whereas the basic dykes pattern shown positive anomalies in Ba, Ti, Sr, Eu and La, being lightly enriched in K, Nd and Zr. Positive Eu anomalies may be interpreted by presence of amphibole. The probable correlation of acid dykes with newer granitic suites of the Pelotas Batholith suggests magmatism with tectonic characteristics late and post-collisionals the Brasiliano Cycle.

Ce travail comporte une étude stratigraphique , une étude structurale et pétrographique des constructions volcaniques de cette vallée aux pieds de l'Etna.

Durch die anthropogene Nutzung sind viele Auen in Mitteleuropa verändert worden, wobei insbesondere die Retentionsflächen stark verringert wurden. Während Auen seit längerem im Fokus der wissenschaftlichen Bearbeitung stehen, gibt es bisher große Wissensdefizite in der Frage der Auenreaktivierungen. Zum einen sind derartige Projekte bisher kaum verwirklicht und zum anderen ist ein langfristiges Monitoring notwendig, um die Anpassung von Biozönosen an die veränderten Standortbedingungen beobachten zu können. Um die Folgen derartiger Eingriffe zu analysieren, bieten sich computergestützte Modellierungen der Landschaftsentwicklung an, wie sie in der vorliegenden Arbeit verwirklicht wurden. Ziel der Arbeit war, mit Hilfe eines Geografischen Informationssystems (GIS) das Entwicklungspotenzial der Landschaft bei verschiedenen Rückdeichungsvarianten auf der Ebene der Biotoptypen darzustellen. Dabei ging es nicht um die Erstellung eines allgemein gültigen Auenmodells sondern um die Erarbeitung eines Modells für einen konkreten Anwendungsfall. Der erarbeitete Ansatz sollte zudem für die landschaftsplanerische Praxis geeignet sein. Als Beispielgebiete wurden Flächen an der Mittleren Elbe bei Rogätz und Sandau, beide im nördlichen Teil von Sachsen-Anhalt, ausgewählt.<br> Die vorliegende Arbeit gliedert sich in zwei Teile. Im ersten Teil werden Erhebungen und Auswertungen als Grundlage der Modellentwicklung dargestellt. Dazu wurden die Biotoptypen der Beispielgebiete flächendeckend erhoben und mit punktuellen Vegetationserhebungen ergänzt. Aus dem Forschungsprojekt "Rückgewinnung von Retentionsflächen und Altauenreaktivierung an der Mittleren Elbe in Sachsen-Anhalt" des Bundesministeriums für Bildung und Forschung (BMBF) standen standortökologische Daten der Hydrologie und Bodenkunde zur Verfügung. Ziel der Auswertung war, Schlüsselfaktoren für Hydrologie und Bodenbedingungen innerhalb der rezenten Aue zu identifizieren, die zur Ausprägung bestimmter Biotoptypen führen.<br> Im zweiten Teil der Arbeit wurde ein Modell für Biotoptypenpotenziale auf den geplanten Rück&ndash;deichungsflächen entwickelt. Das Modell bearbeitet die Datenbank der verwendeten GIS-Dateien, die auf Daten zum Bestand beruht und um solche der Prognose der Standortökologie (Hydrologie und Boden) im Rückdeichungsfalle aus dem BMBF-Projekt erweitert wurde. Weitere Voraussetzung für die Modellierung war die Erarbeitung von Leitbildern, in denen unterschiedliche Nutzungsszenarios für die Landschaft nach Deichrückverlegung hypothetisch festgelegt wurden. Insbesondere die Nutzungsintensität wurde variiert, von einer Variante intensiver land- und forstwirtschaftlicher Nutzung über sogenannte integrierte Entwicklungsziele aus dem BMBF-Projekt bis hin zu einer Variante der Naturschutznutzung. Zusätzlich wurde eine zukünftige Potentielle Natürliche Vegetation modelliert.<br> Eine Überprüfung des Modell fand für den Raum der rezenten Aue in der intensiven Nutzungsvariante statt, die der gegenwärtigen Nutzung am nächsten kommt. Werden Informationen des Bestandsbiotoptyps als Korrekturgröße in das Modell einbezogen, konnte für viele Biotoptypen eine Trefferquote von über 90 % erreicht werden. Bei flächenmäßig weniger bedeutenden Bio&ndash;toptypen lag dieser Wert aufgrund der schmaleren Datenbasis zwischen 20 und 40 %. Als Ergebnis liegt für unterschiedliche Deichvarianten und Leitbilder in den Beispielgebieten die Landschaftsentwicklung als Biotoppotenzial vor. Als eine vereinfachte Regionalisierung der punktuellen Vegetationsdaten wurde im Modell geprüft, inwieweit die modellierten Biotopflächen der Charakteristik der pflanzensoziologischen Aufnahmen aus der rezenten Aue entsprechen. In dem Falle wurde die Pflanzengesellschaft der jeweiligen ökologisch im Rahmen der Untersuchung einheitlichen Flächeneinheit zugeordnet. Anteilig lässt sich damit die Biotopprognosefläche pflanzensoziologisch konkretisieren. Die vorliegende Arbeit gehört zu den bisher wenigen Arbeiten, die sich mit den Folgen von Auenreaktivierung auf die Entwicklung der Landschaft auseinandersetzen. Sie zeigt eine Möglichkeit auf, Prognosemodelle für Biotoptypen und Vegetation anhand begrenzter Felduntersuchungen zu entwerfen. Derartige Modelle können zum Verständnis von Eingriffen in den Naturhaushalt, wie sie die Deichrückverlegungen darstellen, beitragen und eine Folgenabschätzung unterstützen. / Most of the floodplains in Central Europe are highly altered by man. In particular, recent inundation areas have been dramatically reduced. Before the Elbe-flood-disaster of the year 2002 there had already been considerations about combining flood-protection and restoration of floodplains. While research has focused on floodplains for a considerable time, knowledge on the reactivation of floodplains is still significantly lacking. Until now, only a few projects have been realized, and there has not been enough long-term moni&ndash;toring of the adaption of habitats to changing conditions. Computerized models of landscape development, as utilized in the presented work, can help to address these questions. The aim of the study was to show the potential development of the landscape on the scale of biotopes under different scenarios of floodplain expansion by application of a geographic information system (GIS). It was not intended to create a general floodplain-model. The model aimed at a specific applied case and should also be applicable for questions of landscape planning. Two areas near the villages of Sandau and Rogätz at the Middle Elbe River in the north of the German federal state of Saxony-Anhalt were selected.<br> The presented work is divided into two parts. The first describes the sampling and evaluation of data as a basis for modeling. For this, the biotopes were mapped in total in the two study areas. Additionally, vegetation data were collected from selected sites mainly in the grassland and forest-biotopes. Hydrological and soil condition data were available through the project "Rückgewinnung von Retentionsflächen und Altauenreaktivierung an der Mittleren Elbe in Sachsen-Anhalt" of the German Ministry of Education and Science (BMBF). This part of the study aimed to identify the ecological key factors in the recent floodplain that lead to the development of the different biotopes.<br> In the second part of the presented work a model for the potential biotopes on the expanded floodplain after setting back the dikes was developed. The model alters the GIS database and adds a potential biotope. First this database must be expanded to integrate the hydrological and soil data of the BMBF-project for the expanded floodplain. Different hypo&ndash;thetical land use scenarios were assumed and applied to the model. The three different variants of land use adapted from the BMBF-project were intensive land use, land use under conditions of nature-conservation an integration of both extremes. In the case of intensive land &ndash;use arable fields were modeled in areas which are flooded on average only every ten years or less. As a fourth scenario the potential natural vegetation was modeled.<br> An evaluation of the model was made for the recent floodplain under intensive land use conditions, which are close to the current land use. By correcting the models results with information of the current biotope composition, many biotopes could be predicted correctly with 90 % accuracy. For biotopes which are rare in the study area the prediction rate lay between 20 and 40 %. The result of the second part of the presented work was the modeling of the potential biotopes for the different land use scenarios and the different variants of setting back the dikes.<br> Integrated in the model was a module of a simplified regionalization of the vegetation data. It was tested whether the characteristics of the processed unit of the GIS-database fit the results of the vegetation sampling of the first part of the study. Where this was the case, the whole unit was characterized as a phytosociologic vegetation-unit. Thus, for part of the modeling area the biotope-potentials could be expanded with information on the actual vegetation.<br> The present work is one of the few studies so far dealing with the consequences for the landscape of reactivating floodplains which are separated from rivers by dikes. It shows the possibility to use models to predict changes in biotopes and vegetation based on limited field data. Such models can help to understand the altering of nature caused by such impacts and to estimate the possible consequences.

This dissertation explores the reflexive and performative practices found in Mocha Jean Herrup's documentary work, POM, LESBIANFILM, and A FEW GOOD DYKES. By exploiting realism's failure to ever fully represent, reflexive and performative techniques enable a queer discourse. These techniques create 1) a parodic premise that calls attention to the disjunction between documentary's legitimizing conventions and queer as a viable subject, 2) a subjectification of the insider-outsider that troubles distinctions between the audience and the subject and the filmmaker and the subject, and 3) enables the embodied knowledge of queer subjectivity to emerge. / text