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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.
41

The Evolution of Deep-Water Salt-Tectonic Structures, Numerical Modeling Studies applied to the Northwestern Gulf of Mexico

Gradmann, Sofie 11 September 2012 (has links)
Salt tectonics is a key player in the evolution of many worldwide sedimentary basins on rifted continental margins. For more than a century, the evolving structures have been studied; but focus remained primarily on the onshore and shallow-water regions. The evolution of the poorly studied deep-water salt-tectonic structures is the focus of this thesis. Investigations are performed using 2D numerical models that comprise a viscous salt layer overlain by a frictional-plastic passive margin sedimentary sequence from shelf to deep water. This thesis addresses multiple salt-tectonic processes (gravity spreading, evolution of fold belts and salt canopies, diapirism) in a general context but with special focus on the structural evolution of the northwestern Gulf of Mexico (GoM). Here, multiple phases of gravity-spreading induced salt mobilization and thin-skinned deformation occurred throughout the Cenozoic. During the latest, late Oligocene-Miocene phase, the Perdido Fold Belt (PFB) formed from a 4.5km thick pre-kinematic section as a prominent salt-cored deep-water structure above the pinch-out of the autochthonous salt. It is here demonstrated with analytical as well as numerical calculations that the folding of the PFB can have formed by gravity spreading alone without basement tectonics. A requirement for this deformation is very high pore-fluid pressure in the sediments, which effectively reduces the sediments' mechanical strength. These values are refined using numerical models that couple compaction-induced fluid pressure to mechanical deformation. It is shown that very high fluid pressure is only necessary at the landward base of the deforming system; fluid pressure in other regions may remain moderate. This study shows, for the first time, the regional and dynamic evolution of pore-fluid pressure in a continental margin sedimentary system above salt. Additionally, the contribution of `lateral compaction' during fold-belt evolution is addressed. Landward of the PFB, a large-scale canopy developed during the Eocene. Its evolution is studied by investigating three different concepts of canopy evolution that have been proposed in the scientific literature. A canopy evolving via the mechanism of squeezed diapirs is most similar to the Eocene canopy of the northwestern GoM. A canopy evolving via the mechanism of breached anticlines is similar to that observed above the landward end of the PFB. Dynamic diapir growth is addressed in a neutral stress regime under uneven sedimentation employing a new mechanism of diapir initiation and evolution.
42

Influence of canopy cover and landscape structure on proportion of alien and shade-intolerant plant species in forest sites /

Charbonneau, Neil C. January 1900 (has links)
Thesis (M. Sc.)--Carleton University, 2003. / Includes bibliographical references (p. 28-34). Also available in electronic format on the Internet.
43

Comparison of three field methods for forest canopy closure modelling with Landsat imagery /

Lindsay, Andrew Mark, January 1900 (has links)
Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 62-68). Also available in electronic format on the Internet.
44

Crown structure and stem form development in young stands of western hemlock /

Kershaw, John A., January 1993 (has links)
Thesis (Ph. D.)--University of Washington, 1993. / Vita. Includes bibliographical references (leaves [208]-235).
45

A canopy perspective of community dynamics of an old-growth Pseudotsuga-Tsuga forest /

Ishii, Hiroaki. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 106-116).
46

The influence of canopy structure and epiphytes on the hydrology of Douglas-fir forests /

Pypker, Thomas G. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 165-177). Also available on the World Wide Web.
47

Forest biomass estimation with hemispherical photography for multiple forest types and various atmospheric conditions /

Clark, Joshua Andrew. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 160-172). Also available on the World Wide Web.
48

Trees, snow, and flooding : an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest /

Storck, Pascal. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 154-161).
49

Measurement, modeling, and remote sensing of snow cover in areas of heterogeneous vegetation /

Selkowitz, David. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references. Also available on the World Wide Web.
50

Water turnover in species-rich and species-poor deciduous forests xylem sap flow and canopy transpiration /

Gebauer, Tobias, January 2010 (has links) (PDF)
Thesis (Ph. D.)--Universität Göttingen, 2008. / Title from PDF t.p. (viewed July 29, 2010). Includes bibliographical references.

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