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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.
171

Groundwater recharge, flow and discharge in a large crystalline watershed

GLEESON, THOMAS 14 July 2009 (has links)
The objective of this thesis is to constrain the fundamental hydrogeological processes of a large crystalline fractured rock watershed in the Canadian Shield. The fundamental hydrogeological processes of groundwater recharge, flow and discharge are examined individually as well as holistically using a revised conceptual model. The study area is the topographically-subdued Tay River watershed in eastern Ontario where a thin veneer of soil overlies Precambrian crystalline rocks and Paleozoic sediments. Spatial scales from local-scale (100s m2 to 1 km2) to watershed-scale (>100 km2) are examined. Recharge processes are defined using hydrogeological characterization, numerical simulation and isotopic, thermal and hydraulic responses to a snowmelt event. Soil thickness and bedrock transmissivity are highly heterogeneous at the local scale. Cold, 2H depleted snowmelt locally recharged the bedrock aquifer to depths of at least 20 m within two days. This rapid recharge process is localized to areas where the soil is very thin whereas slow recharge is likely widespread. The impact of lineaments on groundwater flow at the watershed-scale is examined using geomatic analysis, hydrogeological characterization, numerical simulation and fracture mapping. Lineaments are interpreted as structural features because the two principal lineament sets are oriented parallel to fracture and fault orientations. The fractured bedrock underlying lineaments generally consists of poorly connected zones of reduced permeability suggesting lineament can be barriers to recharge and flow in this setting. Natural conservative, radioactive, and thermal tracers are integrated with streamflow measurements and a steady-state advective model to delimit the discharge locations and quantify the discharge flux to lakes, wetlands, creeks and the Tay River. The groundwater discharge rate to most surface water bodies is low. Groundwater discharge is distributed across the watershed rather than localized around lineaments or zones of exposed brittle fractures. In the revised conceptual model, recharge is considered two separate processes, groundwater flow is compartmentalized and the discharge flux is considerably lower than porous media watersheds. This thesis provides a better understanding of fundamental hydrogeological processes in a large crystalline fractured rock watershed which impacts the sustainability of water resources and ecology. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-07-13 14:51:25.244
172

Architecture of a Classification System to Evaluate Fault Slip Risk in a Mining Environment

Vatcher, Jessica Lauren 02 June 2012 (has links)
As the depth of mining increases, so does the risk of fault slip related rockbursts. Currently, there is no way to evaluate this risk, however the need for such a system is clear. Fault behaviour in mining environments is the result of a complex interaction between the mining system and the geological system. Although numerous models exist, the wide spectrum of fault behaviour cannot be fully explained. Additionally, these models are phenomenological, resulting in a disconnect between observable parameters and the models of faults. Fault behaviour is dependent upon the strength of the fault, the stresses acting along the fault, the boundary conditions and fault-system stiffness. Significant work exists in the field of earth science attempting to relate properties of the geological system to fault behaviour. In mining environments, these relationships become increasingly difficult to determine due to the time variable nature of mining activities. In order of importance, the following factors influence fault behaviour: excavations, tectonic history and in situ stress, fault system, fault zone geometry, pore pressure, fault zone slip surface and core, blasting, fault zone damage zone and wall rock and temperature. Numerical stress analysis models were created to evaluate the influence of excavations, tectonic history and in situ stress and the fault system on fault behaviour. Excavations were placed in various locations in a fault system. Results showed that there was no clear relationship between excavation location and fault behaviour; small perturbations in the initial state caused significantly different outcomes. The architectures of many classification and decision support systems were evaluated for purposes of a fault slip classification system. Due to the chaotic nature of fault behaviour and the time variable nature of the factors that influence fault slip, a typical classification system is not an appropriate architecture. Instead, it is recommended that a fault slip risk identification system be created, allowing for the incorporation of historical and live data to create a real time response. Artificial neural networks, numerical stress analysis, data from the identified important factors, and seismic data is recommended to form the basis of the fault slip risk identification system. / Thesis (Master, Mining Engineering) -- Queen's University, 2012-06-01 13:17:08.453
173

The Relationship of Laramide Stocks to Regional Structure in Central Arizona

Balla, John Coleman January 1972 (has links)
The area of this study is a northeast trending zone which is approximately ninety miles long, extending from Casa Grande to Globe, Arizona. A number of porphyry copper deposits and barren Laramide stocks occur within this zone. Geological mapping of the various Laramide granitic stocks shows that all of the stocks are composite, epizonal granitic stocks, which are all elongate in a N45°E to N80°E direction. Sulfide bearing veins also trend N45°E to N80°E. The configuration of the stocks defines the structural framework into which they were intruded. The consistent elongation of the granitic stocks shows that the stocks were intruded into a series of parallel, regional faults that trend approximately N60°E to N80°E. Isotopic dating of the stocks shows that they become progressively younger from west to east. Typical isotopic ages are 71 m.y. on the west portion of the zone, and 61 m.y. on the east portion. The porphyry copper deposits also show a trend of decreasing age from west to east. The granitic Laramide stocks are localized where the N45°E to N80°E regional faults intersect the Precambrian granite-Pinal Schist contact. In some cases the regional faults are parallel to the Precambrian granite-Pinal Schist contact, in which case the Laramide stocks are parallel to the contact. The Laramide quartz diorite stocks only occur along the "San Pedro hinge line" and farther to the east. Although the individual quartz diorite stocks are aligned in an east-northeast direction, the overall geographical trend of the quartz diorite is north-northwest. The quartz diorite stocks may also become progressively younger proceeding to the east. The defining of the regional faults or lineaments, based upon the orientation of the Laramide granitic stocks, permits a rather precise projection of these lineaments into areas of complete post-mineral rocks. This allows a large area of post-mineral rocks to be reduced to a rather small area, where exploration for porphyry copper deposits can be intensified.
174

Structural geology along the southeastern margin of the Tucson basin, Pima County, Arizona

Arnold, Leavitt Clark January 1971 (has links)
The Cienega Gap area, located about 27 miles southeast of Tucson, Arizona, has long been noted for its structural complexity. Discordances between sedimentary rocks of Paleozoic, Mesozoic, and Cenozoic age and between these rocks and their granitic basement have led previous workers to propose large -scale northward thrusting in an effort to explain the complex structures observed. An alternative hypothesis invoking southward gliding has been considered by several authors but has been assigned a subordinate role in explaining the deformation. The present study was undertaken in an effort to evaluate the relative suitability of dominantly northward versus dominantly southward movement. In the course of this study nine separate localities were examined and mapped in detail in an effort to evaluate movement direction. Evidence of displacement on low -angle faults or glide surfaces was found in each of the areas examined, and definite evidence of movement direction was recognized in five of these. Large-scale recumbent folding, previously unrecognized in the Colossal Cave and Agua Verde Wash areas, was found to be closely related to local uplift. The asymmetry of the folds, plus a very few observed offsets marginal to the uplifts, were the only criteria found for determining the direction of movement. Evidence of northward, southward, and nearly westward movement was found in the course of the study. Areas in the northern Empire Mountains south of Cienega Gap gave evidence of west – northwestward and northward movement. Areas in the southern Rincon Mountains north of Cienega Gap were found to have undergone dominantly southward movement. Involvement of the Pantano Formation in several of the localities suggests that deformation occurred at least as late as early Oligocene time and probably after middle Miocene time. Cienega Gap was therefore the focus of movement for material which was moving laterally away from areas undergoing uplift in Tertiary time.
175

Kinematics of the Paparoa Metamorphic Core Complex, West Coast, South Island, New Zealand.

Schulte, Daniel January 2011 (has links)
The Paparoa Metamorphic Core Complex developed in the Mid-Cretaceous due to continental extension conditioning the crust for the eventual breakup of the Gondwana Pacific Margin, which separated Australia and New Zealand. It has two detachment systems: the top-NE-displacing Ohika Detachment at the northern end of the complex and the top-SW-displacing Pike Detachment at the southern end of the complex. The structure is rather unusual for core complexes worldwide, which are commonly characterised by a single detachment system. Few suggestions for the kinematics of the core complex development have been made so far. In this study structural-, micrographic- and fission track analyses were applied to investigate the bivergent character and to constrain the kinematics of the core complex. The new results combined with reinterpretations of previous workers’ observations reveal a detailed sequence of the core complex exhumation and the subsequent development. Knowledge about the influence and the timing of the two respective detachments is critical for understanding the structural evolution of the core complex. The syntectonic Buckland Granite plays a key role in the determination of the importance of the two detachment systems. Structural evidence shows that the Pike Detachment is responsible for most of the exhumation, while the Ohika Detachment is a mere complexity. In contrast to earlier opinions the southwestern normal fault system predates the northeastern one. The Buckland Pluton records the ceasing pervasive influence of the Pike Detachment, while activity on the Ohika Detachment had effect on the surface about ~8 Ma later. Most fission track ages are not related to the core complex stage, but reflect the younger late Cretaceous history. They show post core complex burial and renewed exhumation in two phases, which are regionally linked to the development of the adjacent Paparoa Basin and the Paparoa Coal Measures to the southwest and to the inception of seafloor spreading in the Tasman Sea in a larger context.
176

The Giant-con Gold Deposit: A Once-linked Archean Lode-gold System

Siddorn, James P. 31 August 2011 (has links)
The Giant and Con deposits, Yellowknife, Northwest Territories, represent a classic Archean lode-gold deposit now offset by a major Proterozoic fault (West Bay Fault). The link between the Giant and Con deposits is supported by their similarities. However, there are distinct differences between the two deposits in terms of the offset of stratigraphy, response to D2 deformation, geometry, gold mineralization styles, and depth of gold mineralization. Gold mineralization in the Giant-Con system formed over a protracted history of deformation and hydrothermal activity. Early D1 extension resulted in offset and excision of stratigraphy and the formation of refractory gold mineralization within strongly deformed schistose zones and quartz-carbonate veins. The main D2 deformation in the district resulted in the strong overprint of D1 refractory gold mineralization and was associated with the northwest-southeast flattening of the Giant deposit and progressive reverse-dextral shear of the Con deposit. Free-milling gold mineralization is associated with the D2 event, forming deeper in the Giant-Con system, creating a vertical zonation of free-milling quartz-carbonate veins overprinting earlier refractory gold mineralization that formed higher in the system. Ore plunge in the Giant deposit is controlled by the interaction of the original geometry of D1 deformation zones with the effects of D2 flattening. Ore plunge in the Con deposit is controlled by the orientation of F2 fold and B2 boudin axes in auriferous quartz-carbonate veins. D3 reactivation of the deformation zones (probably related to the end of the D2 compressive event) caused local reactivation of structures and is not associated with gold mineralization. D4 Proterozoic faulting offset and segmented the two deposits, including the major offset by the West Bay Fault. A new reconstruction of the West Bay Fault shows that the Con deformation zone is the down dip extension of the Giant deposit and not the Campbell deformation zone as previously thought.
177

Fold-and-thrust belt deformation of the Hongliuhe Group: a Permian tectonic closure record of the Central Asian Orogenic Belt, NW China

Cleven, Nathan January 2011 (has links)
The Early Permian strata of the Hongliuhe Group, NW China, experienced a thin-skinned fold-and-thrust belt style of deformation that recorded the final stages of amalgamation of the Beishan orogenic collage, a part of the Central Asian Orogenic Belt. The Hongliuhe Group was syn-orogenically deposited on an undetermined foreland, with the Mazongshan arc terrane acting as the hinterland. In this study results from detailed mapping combined with a regional analysis elucidate involvement of a northward-dipping subduction system with the collision. Well-preserved fold-and-thrust belt style deformation mapped in the upper stratigraphy of the Hongliuhe Group exhibits dominantly south-southeast verging structure, including shear folding, low-angle thrust ramping, imbrication and duplexing. Restoration of a portion of a mapped outcrop-scale cross-section estimates the accommodation of a minimum of 24% shortening. Lower stratigraphy shows discrete, steeper, north-over-south dip-slip ductile shear zones that bound packages of less deformed Hongliuhe Group strata. Fault displacement is considered to have been prolonged enough to juxtapose basal formations in northerly hangingwalls against upper formations in southerly footwalls. Faulting is closely associated with the creation of large-scale brittle-ductile eye-fold structures that are postulated to be sheath folds. The most examined and mapped structure, 16km wide, is a synclinal structure with axes plunging steeply towards its center. The ellipticity of the exposed bedding traces increases towards the center of the eye-fold, implying a structural relationship with metamorphic shear zones. Except for large-scale folding, the bulk of its strata remain relatively undeformed and have preserved primary soft-sediment deformation structures indicating younging towards the center on both limbs of the synclinal structure. Stratigraphic reconstruction of the Hongliuhe Group that considers the significant faulting shows that the Group's basal conglomerates unconformably overlie a Late-Carboniferous volcanic assemblage. The clast lithotypes of the conglomeratic successions change from polymictic metamorphic rocks at the base to monomictic granitoid clasts mid-section, showing the gradual unroofing sequence of the provenance. The stratigraphic reconstruction shows a general fining upward sequence, transitioning from terrestrial to nearshore marine depositional environments that, and in conjunction with the conglomeratic successions, suggests that the tectonic setting for deposition of the Hongliuhe Group is a foreland basin. Considering the deformation styles reported in this study, the Hongliuhe Group is interpreted to be a foreland fold-and-thrust belt. Stratigraphic reconstruction of the Hongliuhe Group that considers the significant faulting shows that the Group’s basal conglomerates unconformably overlie a Late Carboniferous volcanic assemblage. The clast lithotypes of the conglomeratic successions change from polymictic metamorphic rocks at the base to monomictic granitoid mid-section, showing the gradual unroofing sequence of the provenance. The stratigraphic reconstruction shows a general fining upward sequence through nearshore depositional environments that, and in conjunction with the conglomeratic successions, give interpretation that the tectonic setting for deposition of the Hongliuhe Group is a foreland basin. Considering the deformation styles reported in this study the Hongliuhe Group is interpreted to be a foreland fold-and-thrust belt.
178

Neotectonics And Evolution Of The Eskipazar Basin, Karabuk

Biryol, Berk Cemal 01 July 2004 (has links) (PDF)
Study area, the Eskipazar Basin, is located in the western part of the North Anatolian Fault System. It is a 3-5 km wide, 10 km long and NWSE trending depression, bounded by a complex array of oblique-slip normal faults and strike-slip faults. The Eskipazar Basin is interpreted to be a superimposed basin. The basin fill is composed of two different units deposited under the control of different tectonic regimes, namely the paleotectonic and the neotectonic regimes. The latest paleotectonic fill of the basin is the fluvio-lacustrine deposits of the paleotectonic Eskipazar formation. This formation is unconformably overlain by a group of neotectonic units namely, the Budaklar, the Karkin and the imanlar formations. The unconformity in between these paleotectonic and neotectonic units represents the time interval during which the paleotectonic period comes to end and the neotectonic period started. Thus, onset age of the strike-slip neotectonic regime in the study area is Late Pliocene (&amp / #8764 / 2.6 My). Common basin margin-bounding faults of the Eskipazar Basin are the Kadilar fault set, the Beytarla Fault Zone, the Budaklar fault set, the Arslanlar fault set, the Dibek fault, the Karkin fault, the Boztepe fault and the Acisu fault. These faults display well preserved fault scarps, in places. Morphological expressions of these faults and their geometrical relationships to regional stress system indicate that these faults are mostlystrike-slip faults with normal component. However the Kadilar fault set displays a different characteristic, being the major fault controlling the basin to the west and it is indeed an oblique slip normal fault. Long term seismicity and their epicentral distribution in and very close to the study area suggest that the Eskipazar basin is located in an area of seismic quiescence, nevertheless the morphotectonic expressions of the faults exposing in the basin suggest that these faults are active. Since the most of settlements are located on different lithologies of poorly consolidated deposits of the Eskipazar formation susceptible to landslides, the area is open to future earthquake hazard. Therefore, structures and settlements have to be constructed on strong ground away from active faults.
179

Structural and thermal evolution of the Gulf Extensional Province in Baja California, Mexico: implications for Neogene rifting and opening of the Gulf of California

Seiler, C. January 2009 (has links)
The Gulf of California in western Mexico is a prime example of a young passive margin that is currently undergoing the transition from continental rifting to seafloor spreading. With less than ~25 km of the width of the original continental surface area submerged, the northern Gulf Extensional Province represents a key area to assess the history of strain localisation during the early stages of continental extension. Geological mapping revealed that the basins and ranges of the Sierra San Felipe, located in the hanging wall of the Main Gulf Escarpment, are bounded to the east by an en-echelon array of left-stepping moderate- to low-angle normal faults that represent the next dominant set of normal faults from the break-away fault in direction of transport. Structural displacement estimates suggest up to ~4.5–9 km of broadly east-directed extension on the Las Cuevitas, Santa Rosa and Huatamote detachments. Fault kinematics suggest a transtensional stress regime with NE- to SE-directed extension and permutating vertical and N–S subhorizontal shortening. Clockwise vertical-axis block rotations and constrictional folding of the detachments were an integral part of the late Miocene to Pleistocene deformation history of the San Felipe fault array. This overall constrictional strain regime is indistinguishable from the present-day deformation in the Gulf Extensional Province and indicates that the fault array formed during a single phase of integrated transtensional shearing since rifting began in the late Miocene. / Apatite fission track (AFT) and (U-Th)/He results of Cretaceous crystalline basement samples from the Sierra San Felipe record a three-stage Cenozoic cooling history. Moderate cooling (~4–7ºC/m.y.) during late Paleocene to Eocene times is attributed to progressive down-wearing and bevelling of the ancestral Peninsular Ranges. Beginning at ~45–35 Ma, a period of tectonic quiescence with cooling rates of ≤1ºC/m.y. marks final unroofing of the basement and the development of a regional Oligocene to Miocene peneplain. Thermal modelling of samples from the footwall of the Las Cuevitas and Santa Rosa fault systems indicates that accelerated cooling began at ~9–8 Ma. This cooling pulse is attributed to tectonic denudation of the footwall and implies that faulting initiated synchronously on both detachments at ~9–8 Ma. Late Miocene deformation occurred distributed throughout the Sierra San Felipe, but started waning after the Pacific-North America plate boundary had localised into the Gulf of California by ~4.7 Ma / During a late Pliocene structural reorganisation in the northern Gulf, the locus of extension shifted from the Tiburón to the Delfín basins, thereby initiating strike-slip faulting on the Ballenas fracture zone, a transform fault located approximately 1.5–4.5 km offshore in central Baja California. This is consistent with low-temperature thermochronometric data from two horizontal transects perpendicular to the strike of the transform, which document a pronounced late Pliocene to Pleistocene heating event that is related to the structural and/or magmatic evolution of the transform fault. During reheating, maximum paleotemperatures reached >100–120ºC near the coast, but did not exceed ~60ºC some 5–8 km further inland. Highly non-systematic overprinting patterns are best explained by circulating hydrothermal fluids, which are most likely associated with magmatic leaking along the transform fault. / AFT and (U-Th)/He ages from a vertical profile collected on the Libertad escarpment, which forms part of the Main Gulf Escarpment in central Baja, pre-date Neogene extension and indicate that rift-related denudation was insufficient to expose samples from temperatures higher than the sensitivity zones of the two systems. One sample from the base of the escarpment however, records a middle to late Miocene hydrothermal overprint and suggests that extension in central Baja California likely initiated before ~10–8 Ma.
180

The tectonic history of the Ruker Province, southern Prince Charles Mountains, East Antarctica : implications for Gondwana and Rodinia /

Phillips, Glen. January 2006 (has links)
Thesis (Ph.D.)--University of Melbourne, School of Earth Sciences, 2007. / Typescript. Includes bibliographical references (leaves 197-215).

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