Trends indicate that wildfires have become larger and more intense over the past few decades. Experts suggest this is due to multiple factors including long-term shifts in land use that disrupt the balance of fuels and fire regimes. Research predicts that climate change will exacerbate this trend but will do so in spatially variable ways across the globe, causing increases in fire activity for some regions and decreases for others. In the United States, increased wildfire activity combined with the rapid expansion of residential development in fire-prone land necessitate billions of dollars in suppression efforts every year to protect human lives and property. The confluence of these issues has catalyzed momentum for communities to actively participate in mitigation at the local level. Yet, the precursor to developing effective solutions is to understand the unique environmental and social components of wildfire hazards at local and regional scales and how these components influence the deleterious impact of fire. This thesis takes a case study approach to understanding and communicating wildfire hazard potential in the Edwards Plateau ecoregion of central Texas. Wildfire simulations were conducted at the regional scale to quantify the magnitude of predicted fire behaviors under various spatial and temporal conditions. Simulations were also conducted within two focal communities to illuminate how patterns of wildfire susceptibility overlap with residential development. Finally, an investigation was made into the emergency response infrastructure and mitigation strategies adopted by each of the focal communities. As a result of simulations under drought conditions, forty-four percent of the study area exhibited flame lengths over eleven feet and ninety-six percent of the tree canopy exhibited crown fire activity. Simulations also revealed an increased potential for crown fire activity and extreme flame lengths along the heavily-populated Balcones Escarpment. Third, physical forms of communities appeared to influence the spatial distribution of burn susceptibility. Finally, the infrastructure and practices of the surrounding region impacted community resilience to wildfire hazards. While these findings are specific to the eastern Edwards Plateau, they showcase how mixed methods can be used to build a comprehensive wildfire hazard assessment for a community. / text

The Yidun Terrane in the eastern Tibetan plateau is separated from the Songpan-Ganzi Terrane by the Ganzi-Litang suture zone to the east and Qiangtang Block by the Jinsha suture zone to the west. Both suture zones are marked by eastern Paleo-Tethyan ophiolites. The western part of the Yidun Terrane, the Zhongza Massif, is dominated by Paleozoic sedimentary sequences. In the eastern part, Triassic subduction-related plutonic rocks and volcanic-flysch successions of the Yidun Group are important elements for understanding the evolution of eastern Paleo-Tethys and amalgamation of East Asia. The Yidun Group includes the Lieyi, Qugasi, Tumugou and Lanashan Formations from base upwards. Two major depocenters for the Yidun Group can be recognized. Sedimentary detritus supplying for the northern depocenter were dominantly sourced from the Zhongza Massif and received recycling components in a passive margin setting. In the southern depocenter, the Qugasi Formation accumulated materials from the Zhongza Massif, whereas the Tumugou Formation received additional materials from locally distributed Triassic arc rocks and crystalline basement rocks, which indicates transition from a passive margin to a magmatic arc setting. In the southern Yidun Terrane, (quartz-) dioritic hypabyssal intrusions are spatially associated with andesites and dacites and have zircon U-Pb ages from ~230 to 215 Ma. They have adakitic geochemical features and are divided into the ~230-215 Ma high silica (HSA) and ~215 Ma low silica (LSA) adakitic rocks. The HSA formed from subducted slab melts with limited interaction with the overlying mantle wedge, whereas the LSA were generated from slab melts with more extensive interaction with mantle due to slab break-off at ~215 Ma. In the northern Yidun Terrane, granitic plutons and volcanic rocks occur in two parallel N-S belts. The ~228 Ma volcanic rocks in the Xiangcheng region are adakites generated from slab melts, whereas the ~231-230 Ma volcanic rocks in the Changtai region, including basalts, andesites, dacites and rhyolites, formed in a back-arc setting. The Changtai basalts were produced by low degrees of partial melting of an OIB-like mantle source with minor involvement of subducted slab components. The Changtai andesites/dacites represent evolved members from the basaltic magmas through an AFC process, whereas the rhyolites formed from anatexis of a garnet-bearing crustal source. These volcanic rocks are 4-6 mys older than arc granitic rocks in the northern Yidun Terrane. The spatio-temporal framework of all the subdution-related igneous rocks suggests initiation of subduction of the Ganzi-Litang oceanic lithophere under the southern Yidun Terrane at ~230 Ma, resulting in the adakitic magmatism in the Shangri-La and Xiangcheng regions and the back-arc magmatism in the Changtai region. Subsequently at ~224 Ma, the subduction extended to the northern Yidun Terrane, leading to the formation of the arc granitic plutons. From south to north, the Yidun Terrane was sequentially amalgamated with the Songpan-Ganzi Terrane during the Late Triassic. / published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

Transportation is an integral par t of the tourism industry. It is largely due to the improvement of transportation that tourism has expanded. The impacts on the ecology, degradation of destination sites, tourist experience, and economy has called for a better management of this resource. Transportation can be divided into two parts. One is the mobility infrastructure such as railway and highway, connecting and sometimes dividing the tourism destination. And another is site infrastructure which is in the tourism destination and guides the tourists to explore the place. Few places are as globally significant as the Tibetan Plateau, writes Daniel J Miller. Understanding this means looking at the region from a holistic, ecological standpoint. It has huge biodiversity resource and stores a lot of ice on the mountain. Religious affect this area so that it can remain in the harmony of the people and the nature. The Qinghai-Tibet railway is built for the policy or economic reason after is construction finished in 1st of July, 2006. This transportation greatly changed this area. The tourists’ trend increases 30% in Qinghai and 40% in Tibet in 2007. The income of the tourism also increased. Then the conflict occurred, on the ecological aspect: the wildlife, the One is the stepping destroy by the tourist which may cause soil erosion or vegetation destroy. And the social aspect, tourism reform the local people’s life, increases their income but also challenges the line of their religious faith. The stations along the railway became my focus point. They were like the start point, we can see the government intention, and the economic opportunity. In the meanwhile, it could also be the pollution resource and damage beginning. We can’t just simply stop people from going there. Since the railway is just like a window, advertising the beautiful landscape. If the station can’t access, people will find another way to access, in an uncontrolled way. So it is also an opportunity for expressing a new definition of tourism. Education, love, ecotourism. To make the place love for the people, so that they will have the ownership, they want this landscape keeps forever, so that it be an eternity. My thesis is trying to reach a more sustainable way to develop tourism in this very sensitive area, to create a couple of well-designed station stops which does strict (no access) protection for these areas. My intention is to create a system that combines education and the exploration in tourism. / published_or_final_version / Architecture / Master / Master of Landscape Architecture

Uncertainty is a documentary film about belief systems that human animals use to navigate the unknown and assign meaning to experiences. It acknowledges that we exist amidst the parameters of our own perceptual constructs. Our frameworks for navigation often range in degrees of openness to the unknown and to outside scrutiny. I set out to explore these concepts through interactions with different individuals and social groups, each with their unique templates. I hoped to produce a stimulating film that engaged diverse audiences through diverse content. Structural and stylistic considerations are paramount to my theoretical and post-production reflections on Uncertainty. Deleuze and Guattari's (1988) theory of rhizomes provides a good reference in terms of the cross-fertilisation of ideas, decentralised structure and different states of connection that I hoped to provoke through the film. New documentary theory highlights a trend towards greater interaction between filmmaker, audience and subject (Bruzzi, 2000). This signals a growing understanding that striving for objectivity in documentary is redundant. Although it is a welcome development, discussion could be broadened in relation to filmmaker presence and interactivity, to include style and structure as modes of primary interaction for the filmmaker with the audience and subject. This exegesis approaches expanding the parameters for interaction to examples, such as Uncertainty, where the filmmaker is neither present in image or voice. Texts that offer constellations of ideas, like a rhizome, provide an alternative to those following a more linear progression or centralised argument. Promoting greater connectivity and multiplicity in documentary is congruous with the current developments in communications and technologies.

Freiburg (Breisgau), University, Diss., 2003.

Potsdam, University, Diss., 2003.

Texte remanié de: Th. Ph. D.--Law--Cambridge--University of Cambridge, 1989. / Bibliogr. p. 393-406. Notes bibliogr. Index.

Le plateau de Demerara est un plateau marginal situé le long de la marge de la Guyane française et du Surinam. Grâce aux données récentes acquises lors de la campagne IGUANES, avec des données géophysiques et des carottes sédimentaires, certaines structures sédimentaires illustrent une forte influence du courant sur la construction récente de cette marge.Les géométries sédimentaires suggèrent la présence d'un Système de Dépôt contouritique (CDS) sur ce plateau. Le fond marin est marqué par la présence de structures longitudinales formées par l'activité actuelle: « giant flute casts » ou queues de comètes et des « longitudinal waves ». Sur la base de l'analyse des données chirp et des carottes, la présence de processus contouritiques a été identifiée sur les plateaux marginaux intermédiaires et inférieurs. Cette contourite est probablement induite par la circulation de la NADW. Des structures sédimentaires sont présentes et enregistrées après cet événement : des « comet marks » et des « longitudinal waves ».Le contourite sur ce plateau est constitué de sédiments riches en illustrant le vannage induit par les courants de fond. L'étude des carottes sédimentaires associées à un cadre chrono-stratigraphique permet d'identifier les caractéristiques sédimentaires en fonction de l'intensité du courant. La glauconite, minéral authigénique, est utilisé comme un nouvel outil qui, couplé à des analyses granulométriques et de faciès, permet d’enregistrer les variations du vannage. Sur le plateau de Demerara, la sédimentation indiquent des taux d'accumulation sédimentaire faibles et des courants de fond intenses pendant les périodes glaciaires.La présence de contourites le long du plateau de Demerara et le long d'autres plateaux marginaux montre l'impact fort de tels reliefs bathymétriques sur la circulation océanique. / The Demerara Plateau is a marginal plateau located along the French Guyana and Surinam margin. Thanks to the recent data acquired during the IGUANES cruise, with geophysical data and sedimentary cores, some sedimentary structures illustrate a strong current influence on the recent building of this margin. The sedimentary geometries suggest the presence of a Contourite Depositional System (CDS). The seafloor is marked by the presence of longitudinal structures formed by the current activity: giant flute clasts or comet marks, and longitudinal waves. Based on the chirp data analysis and on cores, some sedimentary domains are identified on the Demerara marginal plateau. The intermediate and the lower marginal plateaus are affected by contouritic process with two moats and a mounded elongated drift. This contourite is likely induced by the NADW circulation. The contourite on this plateau is made of glauconitic rich sediments inside the moat showing the winnowing effect induced by the bottom currents. The detailed study of sedimentary cores associated with a chronostratigraphic framework allows identifying the sedimentation features depending on current intensity through time. The glaucony authigenic mineral is used as a main proxy, coupled with grain-size and facies analyses, for inferring the degree of winnowing at the sediment-water interface. On the Demerara plateau, the sedimentation suggests low sediment accumulation rates and quite energetic bottom currents during ice periods.The presence of contourites along the Demerara Plateau and along other marginal plateaus shows the strong impact of such deep-sea marginal bathymetric reliefs on the oceanic circulation.

Les marges transformantes, formées par le coulissage des plaques lors des premières étapes de l’ouverture océanique, ont été peu étudiées relativement aux marges divergentes. La marge de Côte d’Ivoire-Ghana fait figure d’exemple-type, et l’absence d’inventaire exhaustif ainsi que le peu d’étude de marges transformantes conjuguées entraîne une méconnaissance de la véritable diversité de ce type de marge. Deux approches ont été abordées dans ce mémoire. La première a consisté à les inventorier dans le monde à partir d’une méthodologie simple. Elles ont ensuite été comparées (physiographie et structure). La deuxième s’est concentrée sur l’étude tectono-sédimentaire des marges transformantes conjuguées des plateaux de Demerara et de Guinée. L’inventaire des marges transformantes a montré que les marges transformantes représentent 30% des marges passives. Leur distribution au sein de domaines océaniques ouverts de façon très oblique ou à l’intersection entre grands domaines reflète des conditions d’initiation spécifiques. 30% des marges transformantes se trouvent notamment en bordure d’un plateau marginal ; un type de bassin à l’histoire double nouvellement défini, qui semble associé à un fort amincissement crustal. Par ailleurs, on montre que les marges transformantes présentent des architectures diverses et sont souvent segmentées. L’étude des plateaux marginaux de Demerara et Guinée a permis de montrer qu’elles se mettent en place au niveau d’un domaine pré-aminci, sans doute guidées par des structures préexistantes. La nature du soubassement des plateaux est discutée : éventails sédimentaires ou volcaniques type SDR. La formation et l’évolution des marges transformantes en bordure des deux plateaux a été accompagnée de déformations intenses à l’approche des frontière océan-continents ainsi que de plusieurs épisodes de soulèvement et subsidence successifs de la bordure transformante, dont les origines et mécanismes sont discutés. / Transform margins form by transform motion between plates during early stages of oceanic spreading. They have been poorly studied in comparison with divergent margins, at least for the last 15 years. The Côte d’Ivoire-Ghana margin represents the best known example of a transform margin and is often considered as a model. However, the lack of a global complete inventory of such margins may lead to underestimate their diversity. Two approaches have been developed in this work. The first one consisted in a compiling world transform margins using a systematic and simple methodology. Those margins have then been compared (physiography, structure). In a second approach we analysed the tectono-sedimentary evolution of the Demerara and Guinea conjugated transform-derived plateaus. The worldwide review of transform margins shows that those represent 30% of the existing passive margins. Their distribution inside very oblique oceanic domains, and at the intersection between oceanic domains of contrasted ages, reflects specific initiation conditions. 30% of those transform margins locate on the edge of marginal plateaus —newly defined type of basins— that seem to be associated with important crustal thinning. Furthermore, this inventory shows that transform margins display a great variety of architectures. The Demerara and Guinea marginal plateaus are bounded by transform margins that occur on an already thinned crust, probably along a preexisting structure. The nature of these plateaus basement is discussed: sedimentary or volcanic SDRs fan-shaped units? During the Equatorial Atlantic opening, the formation and evolution of Demerara and Guinea transform margins were accompanied by intense deformations close to the continent-ocean boundary and by several successive uplift and subsidence phases along the plateaus borders. Their origin and mechanisms are discussed.

This study identifies the biogeographic factors that structure small mammal communities on mountains of the Colorado Plateau and adjacent regions. Forty six isolated ranges were characterized across a 5-state study area encompassing the Colorado Plateau, including the central high plateaus of Utah and the Basin and Range Province (i.e. the Great Basin and mountains of Arizona and New Mexico). Presence/absence data of 25 montane mammal species were used to explore the interactions between historical and ecological processes affecting local and regional diversity patterns. Multivariate analyses, such as non-metric dimensional scaling, were used to explore factors which influence community composition. Results of these analyses revealed the Colorado River as a significant biogeographic barrier that affects montane mammal community structure. MtDNA cytochrome b sequence variation was analyzed among populations of the long-tailed vole, Microtus longicaudus, sampled from five interior ranges of the Colorado Plateau- Abajo, LaSal, Henry, and Chuska Mts., and Boulder Mountain of the Aquarius Plateau-and analyzed using traditional phylogenetic approaches (parsimony and likelihood) as well as nested clade analysis. Results support previous documentation of a major east-west phylogeographic break occurring between populations southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations, which include a central clade, a northwest clade, and an Alaskan island clade. Evidence also supports differentiation of a 'southern Rockies' clade and a distinct 'southwest island' clade. Populations of M. longicaudus north and west of the Colorado River (Boulder and Henry Mts.) share two haplotypes, form a well-supported subclade with populations from the Kaibab plateau, and are closely related to the Northwest clade. Past approaches to studying montane mammal communities utilizing theory based on island biogeography have overemphasized area and isolation as the only forces structuring insular communities. As a result, there has been a lack of recognition of the influences of environmental factors, species turnover, and barriers that create and maintain regional diversity on the Colorado Plateau and adjacent areas.