The North Alpine Foreland Basin (NAFB) comprises sediments of late Eocene to middle Miocene age. The earliest deposits are the North Helvetic Flysch which are exposed in the regions of Glarus and Graubunden, eastern Switzerland. The Taveyannaz sandstones are the first thrust wedge (southerly) derived sediments of the North Helvetic Flysch. The Taveyannaz basin was divided into two sub-basins by a thrust ramp palaeohigh running ENE/WSW (parallel to the thrust front). Palaeocurrent directions were trench parallel towards the ENE. Sedimentation in the Inner basin (140m thick) is characterised by very thick bedded turbidite sands generated by thrust induced seismic events confined within the thrust-top basin. The Outer basin (240m min. thickness) comprises 10-15 sand packages (5-100m thick) formed by turbidite sands which are commonly amalgamated. Sedimentation in the Outer basin is considered to have been controlled by thrust-induced relative sea-level variations. The Inner basin underwent intense deformation at the sediment/water interface prior to the emplacement of a mud sheet over the basin whilst the sediments were partially lithified. Later tectonic deformation involved fold and thrust structures detaching in the underlying Globigerina marls. The stratigraphy of the NAFB can be considered as two shallowing upward megasequences separated by the base Burdigalian unconformity. This stratigraphy can be simulated by computer by simplifying the foreland basin/thrust wedge system into 4 parameters: 1) the effective elastic thickness of the foreland plate, 2) a transport coefficient to describe the erosion, transport and deposition of sediment, 3) the surface slope angle of the thrust wedge, 4) the thrust wedge advance rate. The Alpine thrust wedge underwent thickening during the underplating of the External Massifs at about 24-18Ma. This event is simulated numerically by slowing the thrust wedge advance rate, and increasing the slope angle and keeping all other parameters constant. This event causes rejuvenation of the forebulge, and erosion of the underlying stratigraphy, so simulating the base Burdigalian unconformity without recourse to eustasy or anelastic rheologies to the foreland plate.

Turkey is widely accepted to have formed from a collage of microcontinents that rifted from the northern margin of Gondwana and assembled from the Mesozoic to Mid Cenozoic in response to the closure, collision and suturing of numerous oceanic strands in the Eastern Mediterranean. Sedimentary-tectonic basins, which formed during ocean basin closure, can yield important information about the evolution, timing and processes related to the closure of these oceanic strands. The Darende Basin and the adjacent Hekimhan Basin are two sedimentary-tectonic basins which developed during the collision and suturing of the Neotethys Ocean in the Eastern Mediterranean. The Darende and Hekimhan Basins developed as part of the northern margin of the Tauride microcontinent during the collision and suturing of Neotethys. Both basins exhibit a Jurassic to Cretaceous regional carbonate platform 'basement' overlain by a dismembered ophiolite, which was emplaced southwards during the Late Cretaceous. The basins then developed in two main phases: In the Darende Basin the first phase is characterised by non-marine clastic sediments, overlain by transgressive shallow-marine rocks. In the Hekimhan Basin, hemi-pelagic facies are deposited synchronously with the eruption of within plate-type alkaline basaltic-trachytic lavas and associated volcaniclastic sediments (later intruded by a syenitic pluton) under an extensional tectonic regime. A Paleocene-aged unconformity followed. A second phase of basin evolution during the Eocene is characterised in both basins by the deposition of variable sedimentary facies including conglomerate, sandstone, marl, shallow-marine nummulitic limestone and evaporites (and localised basaltic eruptions). These record successive deepening, shallowing and finally emergence of both basins during the Late Eocene. The Oligocene is represented by continental fluvial deposits that are only exposed in the Hekimhan Basin. The deposition of faunally diverse, shallow-marine, Miocene limestones, Pliocene subaerial basalts and Pliocene-Recent continental deposits in both basins completes the sequence. The following tectonically and eustatically controlled stages of basin development are inferred: 1) Late Cretaceous extension initiated basin development (after ophiolite emplacement), possibly related to immediate isostatic compensation and on-going slabpull during northward subduction of the remaining Neotethyan oceanic crust. The eruption of within-plate lavas and the intrusion of alkaline syenite bodies in the Hekimhan Basin reflect this extensional setting; 2) Emergence of the Darende and Hekimhan Basins in the latest Cretaceous was possibly controlled by regional flexural uplift as the down-going plate approached the subduction zone to the north (and was possibly also influenced by eustatic sea-level change); 3) Early Eocene flexural subsidence related to ‘soft collision’ of the Tauride microcontinent with Eurasia, coupled with a significant eustatic sea level rise, allowed sedimentation to resume; 4) Mid-Late Eocene ‘hard collision’ resulted in regional uplift, progressive isolation and subaerial exposure of the basins; 5) Suture tightening and compression, during the Late Eocene- Miocene, resulted in reactivation of pre-existing extensional faults and terminated marine sedimentation. Both basins were affected by predominantly sinistral strike-slip faulting during the Plio-Quaternary westward tectonic escape of Anatolia.

No description available.

This dissertation investigates the temporal and spatial variations in deformation of the Calabrian forearc during the evolution of the subduction-rollback system. In addition to contributing new data to the area, I develop three strategies for understanding recent and active deformation by linking long-term structural data with short-term geomorphological data. First, setting a “baseline” of deformation is important when studying plate boundaries. Through the structural mapping of an uplifted forearc basin, I conclude that rapid rollback is characterized by tectonic quiescence in the Calabrian forearc when it is located far from collision (from ~12 Ma – ~5 Ma). This “baseline” provides a framework from which I interpret younger phases of deformation. In the middle Pliocene (~5-4 Ma), an arc-parallel shortening event characterizes the first stage of forearc collision in my field area. These folded sediments are later tilted, but structural data from the field cannot constrain the age or structure responsible for this youngest phase of deformation. The Neto River dissects this tilted surface opening up the possibly of linking structural data with geomorphic data from river erosion. I collected a transect of river sediment samples for 10Be analysis to determine variation in catchment-wide erosion rates through the modern day deformation. I, then, developed a numerical model that describes changes in erosion rate through time with the structural growth of the tilted surface. The model is the first of its kind to use catchment-wide erosion rates to constrain a structural model. The model results constrain the age of the beginning of deformation to 850 ka and suggest that a fold with a migrating hinge caused tilting of the surface. The model provides the basis for my hypothesis that the forearc is experiencing an arc-perpendicular shortening strain, which contradicts conclusions from GPS data and the well-documented extension in the western part of the forearc. To further investigate surficial deformation, I carry out geomorphic analyses of 87 river drainages. I interpret my findings in terms of structural framework and find that surficial deformation varies tremendously from east to west. The rivers draining eastward are characterized by low concavities and higher erosion rates, consistent with shortening. While just 50 km away, the westward-draining rivers are characterized by high concavities and lower erosion rates, consistent with extension. Overall, the drainages are shifting from east-draining to west-draining, likely due to the topographic growth that decreases concavities on the eastern side. Although a new interpretation, this finding is consistent with previous structural, paleomagnetic, and seismological datasets. In each of the chapters, I interpret the structural and geomorphic data in a regional framework. This extra step is critical in interpreting deformation along active plate boundaries because it is highly variable and can be seemingly contradictory. In my final chapter, I present a cross section of the plate boundary that incorporates my data and interpretations from the geomorphic results and the most recent structural event as well as data from multiple other sources (GPS, seismological, paleomagnetics, structural, tomographic, geomorphic, etc.). This approach confirms the importance of boundary conditions on deformation in a subduction-rollback system. More intriguingly, the cross-section highlights the spatial variations along the surface and with depth suggesting that there is significant interplay between active structures.

The Great Basin is a region of the Basin and Range Physiographic Province, which is completely isolated hydrologically from the sea. All precipitation that falls within the Great Basin is lost from the land surface or from the surf ace of closed inland lakes through evapotranspiration. Playas are often found at the base of these undrained basins. This study focuses on subsurface groundwater flow patterns in closed basins. Because all discharge from the basins occurs via evapotranspiration on and near the playa, the water table of the aquifer beneath the playa is often just below the ground surface. Fluctuations of the water table due to climatic events cause the water table to rise and dissolve the salts on the playa surface. This mass transfer can produce density gradients that in turn cause flow. This study is an extension of the work performed by Duffy and Al-Hassan (Duffy and Al-Hassan 1988) in which numerical experiments were used to show that the free convection, caused by the variation in density of the bulk fluid propenies, appears to play an important role in determining the patterns of groundwater flow beneath the playa. Their work considered only homogeneous, isotropic porous media in symmetric basins. The effects of anisotropy, periodic stratification, and asymmetric basins on the groundwater flow and transport patterns was studied here. Dimensionless parameters, the Rayleigh number and the salt nose length, L0*, were defined for each of the systems incorporated and were shown to be linearly related. The implication of this relationship is that the Rayleigh number can be used to predict basin-scale circulation patterns in the hypothetical closed basins studied. It was also determined that an equivalent anisotropic system could be defined for a horizontally stratified aquifer in order to predict basin-scale circulation patterns. An equivalent isotropic system was defined for each anisotropic system in a similar manner.

Lower Cretaceous basins associated with the Hohhot detachment in the Daqing Shan of Inner Mongolia, China, allow us to better understand the tectonic evolution of extensional basins formed in association with detachment faulting and metamorphic core complex formation. The six basins, informally named N1, N2, S1, S2, S3, and S4, are located in different structural settings, or depozones, throughout the detachment-metamorphic core complex setting, and although all basins are consistent with previously proposed models for supradetachment basin sedimentation, second-order variability in sedimentary style is exerted by these distinct structural settings. The basins are composed of coarse, predominantly footwall derived, conglomerate deposited by masswasting and alluvial fan processes. Paleocurrent direction is generally southerly, indicating transverse transport away from the bounding detachment fault. Two of the basins, N2 and S3, provide us with an understanding of the temporal evolution of supradetachment basins in the upper plate of a metamorphic core complex. These basins were joined in their early stages, but were later separated as extensional unroofing exhumed the lower plate of the core complex and folded the master detachment fault, causing it to propagate a new splay to the surface. Continued extension was accommodated on this new splay, allowing for continued deposition of Lower Cretaceous strata above the detachment fault on the southern flank of the Daqing Shan antiform. Another basin, S2, displays the same stratigraphy and records a similar evolution, but we speculate that it formed separately in a primary corrugation of the master detachment fault. The only unit exposed in basin S4, located near the eastern end of the detachment, is the uppermost unit. Paleocurrent and provenance data are similar to other basins. Thus, it strongly resembles the other basins in spite of the magnitude of extension. Basin S1 is located in an intra-hanging wall setting and resembles the other basins with the exception of a centrally located fine-grained interval. Basin N1 was filled by similar depositional processes, but the proportions of fill that these processes are responsible for is variable in comparison to the other Lower Cretaceous basins in the Daqing Shan. This study establishes that the basins described are all of similar geometry and depositional style, and that supradetachment basins of this style may occur in various positions within a detachment-metamorphic core complex setting, regardless of proximity to the exhumed metamorphic core and magnitude of extension.

Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisors: Jack B. Gingrich and Charles E. Mason, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2006. / Bibliography: leaves 238-247. Also available online.

Reliable hydrological model simulations are the result of numerous complex interactions among hydrological inputs, landscape properties, and initial conditions. Determination of the effects of these factors is one of the main challenges in hydrological modelling. This situation becomes even more difficult in cold regions due to the ungauged nature of subarctic and arctic environments.<p> This research work is an attempt to apply a new approach for modelling snowcover ablation and snowmelt runoff in complex subarctic environments with limited data while retaining integrity in the process representations. The modelling strategy is based on the incorporation of both detailed process understanding and inputs along with information gained from observations of basin-wide streamflow phenomenon; essentially a combination of deductive and inductive approaches. The study was conducted in the Wolf Creek Research Basin, Yukon Territory, using three models, a small-scale physically based hydrological model, a land surface scheme, and a land surface hydrological model. The spatial representation was based on previous research studies and observations, and was accomplished by incorporating landscape units, defined according to topography and vegetation, as the spatial model elements.<p> Comparisons between distributed and aggregated modelling approaches showed that simulations incorporating distributed initial snowcover and corrected solar radiation were able to properly simulate snowcover ablation and snowmelt runoff whereas the aggregated modelling approaches were unable to represent the differential snowmelt rates and complex snowmelt runoff dynamics. Similarly, the inclusion of spatially distributed information in a land surface scheme clearly improved simulations of snowcover ablation. Application of the same modelling approach at a larger scale using the same landscape based parameterisation showed satisfactory results in simulating snowcover ablation and snowmelt runoff with minimal calibration. Verification of this approach in an arctic basin illustrated that landscape based parameters are a feasible regionalisation framework for distributed and physically based models. In summary, the proposed modelling philosophy, based on the combination of an inductive and deductive reasoning, is a suitable strategy for reliable predictions of snowcover ablation and snowmelt runoff in cold regions and complex environments.

Reliable hydrological model simulations are the result of numerous complex interactions among hydrological inputs, landscape properties, and initial conditions. Determination of the effects of these factors is one of the main challenges in hydrological modelling. This situation becomes even more difficult in cold regions due to the ungauged nature of subarctic and arctic environments.<p> This research work is an attempt to apply a new approach for modelling snowcover ablation and snowmelt runoff in complex subarctic environments with limited data while retaining integrity in the process representations. The modelling strategy is based on the incorporation of both detailed process understanding and inputs along with information gained from observations of basin-wide streamflow phenomenon; essentially a combination of deductive and inductive approaches. The study was conducted in the Wolf Creek Research Basin, Yukon Territory, using three models, a small-scale physically based hydrological model, a land surface scheme, and a land surface hydrological model. The spatial representation was based on previous research studies and observations, and was accomplished by incorporating landscape units, defined according to topography and vegetation, as the spatial model elements.<p> Comparisons between distributed and aggregated modelling approaches showed that simulations incorporating distributed initial snowcover and corrected solar radiation were able to properly simulate snowcover ablation and snowmelt runoff whereas the aggregated modelling approaches were unable to represent the differential snowmelt rates and complex snowmelt runoff dynamics. Similarly, the inclusion of spatially distributed information in a land surface scheme clearly improved simulations of snowcover ablation. Application of the same modelling approach at a larger scale using the same landscape based parameterisation showed satisfactory results in simulating snowcover ablation and snowmelt runoff with minimal calibration. Verification of this approach in an arctic basin illustrated that landscape based parameters are a feasible regionalisation framework for distributed and physically based models. In summary, the proposed modelling philosophy, based on the combination of an inductive and deductive reasoning, is a suitable strategy for reliable predictions of snowcover ablation and snowmelt runoff in cold regions and complex environments.