Η περιοχή μελέτης χαρακτηρίζεται από την μορφολογία του ανώτατου Πλειστοκαίνου και Ολοκαίνου. Η μορφολογία αυτή περιγράφεται από την παρουσία μιας Τυρρήνιας αναβαθμίδας που κλίνει προς τα δυτικά μπροστά από την λοφοσειρά Σκόλις. Η αναβαθμίδα αυτή είναι μια διαβρωσιγενής χερσαία επιφάνεια που επικαλύπτεται από μια φάση ερυθρών κροκαλοπαγών και ταρατσώνει μια φάση απολιθωματοφόρων θαλασσίων παρακτίων αποθέσεων. Ένας "ρηξιγενής κρημνός" διαχωρίζει την προαναφερθείσα αναβαθμίδα από ένα παράκτιο πεδίο. Το πεδίο αυτό χαρακτηρίζεται από πρόσφατες αποθέσεις ελών, πεδιάδων πλημμύρας και παρακτίων ράχεων και αμμολόφων και χαρακτηρίζεται από την παρουσία της λιμνοθάλασσας του Κοτυχίου και της σημερινής ακτογραμμής. Τα πιο πάνω ιζήματα έχουν αποτεθεί ασύμφωνα πάνω στην Ιόνια ζώνη. / --

I seek to reconstruct the balance between sediment storage and yield across multiple drainage basin scales in a large (1 230 km2) watershed in the Northern Cascade range, British Columbia and Washington. Chilliwack Valley and surrounding area has been the site of numerous studies that have detailed much of its Quaternary sedimentary history. In the present study this information is supplemented by reconstruction of the morphodynamic trajectory of the river valley though the Holocene Epoch, and development of a sediment transfer model that describes the relaxation from the Fraser glaciation. The total Holocene sediment yield is estimated from basins across several scales using field and remotely sensed evidence to constrain the historical mass balance of delivery to higher order tributary basins. Rates of hillslope erosion are estimated using a diffusion-based relation for open slopes and delimitating the volume evacuated from major gully sources. Digital terrain models of paleo-surfaces are constructed to calculate total sediment erosion and deposition from tributary valleys and the mainstem. Chilliwack Lake has effectively trapped the entire post-glacial sediment load from the upper catchment (area = 334 km2), allowing to compare this "nested" system with the larger catchment. Rates of lake sediment accumulation are estimated using sediment cores and paleomagnetism. These are compared with accumulation rates in the terminal fan inferred from radiocarbon dating of fossil material, obtained by sonic drilling in the apex gravels. A sediment budget framework is then used to summarize the net transfer of weathered material and glacial sediments from the hillslope scale to the mainstem. The long-term average sediment yield from the upper basin is 62 +/- 9 t/km2/yr; contemporary yield is approximately 30 t/km2/yr. It is found that only 10-15% of the material eroded from the hillslopes is delivered to mouths of the major tributaries; the remaining material is stored at the base of footslopes and within the fluvial sedimentary system. Since the retreat of Fraser Ice from the mouth of the valley, Chilliwack River delivered over 1.8 +/- 0.21 km3 of gravel and sand to Vedder Fan in the Fraser Valley. In the sediment budget developed here, roughly 85% of that material is attributed to glacial sources, notably the Ryder Uplands and glacial valley fills deposited along the mainstem, upstream of Tamihi Creek. In tributary valleys, local base-level has fallen, leading to the evacuation of deep glacial sedimentary fills. Many of the lower reaches of major tributaries in upper Chilliwack Valley (e.g. Centre and Nesakwatch Creeks) remain primarily sediment sinks for slope-derived inputs, since base-level fall has not been initiated. In distal tributaries (Liumchen, Tamihi and Slesse creeks), paraglacial fans have been incised or completely eroded, entrained by laterally active channels. A transition from transport-limited to supply-limited conditions has been effected in many of these reaches. Slesse Creek has struck an intermediate balance, as it continues to remobilize its considerable sediment stores. It functions today as the sedimentary headwaters of Chilliwack Valley. Using grain size data and fine-sediment geochemical data gathered from Chilliwack River over the course of several field seasons, a simple finite-difference, surface-based sediment transport model is proposed. The aim of the model is to integrate the sediment-balance information, as inferred from estimates of hillslope erosion and valley storage, and physical principles of sediment transport dynamics to reproduce the key characteristics of a system undergoing base-level fall and reworking its considerable valley fill during degradation. Such characteristics include the river long profile, the river grain-size fining gradient, the percentage of substrate sand, and the diminution of headwater granite lithology in the active load. The model is able to reproduce many of the characteristics, but is not able to satisfy all criteria simultaneously. There is inevitably some ambiguity as to the set of parameters that produce the "right" result, however the model provides good insight into long-term interactions among parameters such as dominant discharge, grain size specifications, abrasion rates, initial topography, hiding functions, and hydraulic parameters.

<p> Digital soil mapping (DSM) is a rapidly growing area of soil research that has great potential for enhancing soil survey activities and advancing knowledge of soil-landscape relationships. To date many successful studies have shown that geographic datasets can be used to model soil spatial variation. This thesis addresses two issues relevant to DSM, scale effects on digital elevation models, and predicting soil properties. The first issue examined was the effect of spatial extent on the calculation of geometric land surface parameters (LSP) (e.g. slope gradient). This is a significant issue as they represent some of the most common predictors used in DSM. To examine this issue two case studies were designed. The first evaluated the systematic effects of varying both grid and neighborhood size on LSP, while the second examined how the correlation between soil and LSP vary with grid and neighborhood size. Results of the first case study demonstrate that finer grid sizes were more sensitive to the scale of LSP calculation than larger grid sizes. While the magnitude of effect was diminished when comparing a high relief landscape to a low relief landscape, the shape and location of the effect was similar. Results of the second case study showed that the correlation between soil properties and slope curvatures were similarly optimized when varying the spatial extent, but that the effect was more sensitive to grid size than neighborhood size. Slope gradient also showed significant correlations with some of the soil properties, but was not sensitive to changes in grid or neighborhood size.</p><p> The second study attempted to predict numerous physical and chemical soil properties for several depth intervals (0-15, 15-60, 60-100, and 100-150-centimeters), using generalized linear models (GLM) and geographic datasets. The area examined was the Upper Gauley Watershed on the Monongahela National Forest, which covers approximately 82,500 acres (33,400 hectares). This watershed represents a complex landscape with contrasting geologic strata, deciduous and coniferous forests, and steep slopes. Given this landscape diversity it was still possible to fit GLM which explained on average 38 percent of the adjusted deviance for rock fragment content, and exchangeable calcium and magnesium, and phosphorus. Some of the most commonly selected environmental predictors were slope curvatures, lithology types, and relative slope position indices. This seems to validate the prominence of these variables in theoretical soil-landscape models. Had the correlation between the soil properties and slope curvatures not been optimized by varying the spatial extent, it is likely that another less suitable LSP would have been selected.</p>

I seek to reconstruct the balance between sediment storage and yield across multiple drainage basin scales in a large (1 230 km2) watershed in the Northern Cascade range, British Columbia and Washington. Chilliwack Valley and surrounding area has been the site of numerous studies that have detailed much of its Quaternary sedimentary history. In the present study this information is supplemented by reconstruction of the morphodynamic trajectory of the river valley though the Holocene Epoch, and development of a sediment transfer model that describes the relaxation from the Fraser glaciation. The total Holocene sediment yield is estimated from basins across several scales using field and remotely sensed evidence to constrain the historical mass balance of delivery to higher order tributary basins. Rates of hillslope erosion are estimated using a diffusion-based relation for open slopes and delimitating the volume evacuated from major gully sources. Digital terrain models of paleo-surfaces are constructed to calculate total sediment erosion and deposition from tributary valleys and the mainstem. Chilliwack Lake has effectively trapped the entire post-glacial sediment load from the upper catchment (area = 334 km2), allowing to compare this "nested" system with the larger catchment. Rates of lake sediment accumulation are estimated using sediment cores and paleomagnetism. These are compared with accumulation rates in the terminal fan inferred from radiocarbon dating of fossil material, obtained by sonic drilling in the apex gravels. A sediment budget framework is then used to summarize the net transfer of weathered material and glacial sediments from the hillslope scale to the mainstem. The long-term average sediment yield from the upper basin is 62 +/- 9 t/km2/yr; contemporary yield is approximately 30 t/km2/yr. It is found that only 10-15% of the material eroded from the hillslopes is delivered to mouths of the major tributaries; the remaining material is stored at the base of footslopes and within the fluvial sedimentary system. Since the retreat of Fraser Ice from the mouth of the valley, Chilliwack River delivered over 1.8 +/- 0.21 km3 of gravel and sand to Vedder Fan in the Fraser Valley. In the sediment budget developed here, roughly 85% of that material is attributed to glacial sources, notably the Ryder Uplands and glacial valley fills deposited along the mainstem, upstream of Tamihi Creek. In tributary valleys, local base-level has fallen, leading to the evacuation of deep glacial sedimentary fills. Many of the lower reaches of major tributaries in upper Chilliwack Valley (e.g. Centre and Nesakwatch Creeks) remain primarily sediment sinks for slope-derived inputs, since base-level fall has not been initiated. In distal tributaries (Liumchen, Tamihi and Slesse creeks), paraglacial fans have been incised or completely eroded, entrained by laterally active channels. A transition from transport-limited to supply-limited conditions has been effected in many of these reaches. Slesse Creek has struck an intermediate balance, as it continues to remobilize its considerable sediment stores. It functions today as the sedimentary headwaters of Chilliwack Valley. Using grain size data and fine-sediment geochemical data gathered from Chilliwack River over the course of several field seasons, a simple finite-difference, surface-based sediment transport model is proposed. The aim of the model is to integrate the sediment-balance information, as inferred from estimates of hillslope erosion and valley storage, and physical principles of sediment transport dynamics to reproduce the key characteristics of a system undergoing base-level fall and reworking its considerable valley fill during degradation. Such characteristics include the river long profile, the river grain-size fining gradient, the percentage of substrate sand, and the diminution of headwater granite lithology in the active load. The model is able to reproduce many of the characteristics, but is not able to satisfy all criteria simultaneously. There is inevitably some ambiguity as to the set of parameters that produce the "right" result, however the model provides good insight into long-term interactions among parameters such as dominant discharge, grain size specifications, abrasion rates, initial topography, hiding functions, and hydraulic parameters.

Bibliography: leaves 291-315. / x, 315 leaves, [9] leaves of plates : ill. (chiefly col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1998?

8 fold. maps in end pocket of v.2 / 2 v. : ill. photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 1977

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xii, 219 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 105-108).

Thesis (M.S. - Geosciences)--University of Arizona. / Includes bibliographical references.

Habilitationsschrift--Würzburg. / Summary also in English. Bibliography: p. 190-201.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 124-137). Also available online in ProQuest, free to University of Oregon users.