La distribution spatiale des massifs UHP/BT montre que leur exhumation est un phénomène 3D qui a lieu uni-quement dans des zones particulières des chaînes de montagnes caractérisées par une complexité structurale et/ou géométrique. Dans les expériences de modélisation thermomécanique 2D de la subduction continentale en régime de faible compression, nous obtenons l'exhumation de roches HP depuis des profondeurs d'environs 70 km. La croûte continentale subduite plus profondément dans l'asthenosphere devient trop chaude (peu résis-tante). Elle se détache du manteau continental subduit, flue verticalement et se sous plaque sous la plaque chevauchante. La subduction continentale en régime de forte compression peut provoquer la rupture de la plaque chevauchante dans l'arc volcanique ou le bassin arrière arc aboutissant à la subduction du bloc avant arc ou de la plaque d'arc. La croûte continentale subduite avec ces unités peut atteindre 200 km de profondeur en étant gui-dée par ces unités et le manteau continental subduit. Dans ces conditions, la croûte est soumise aux conditions UHP/BT, mais elle ne peut pas être exhumé dans un contexte 2D. Nous montrons numériquement en 3D, que la subduction le long d'une frontière de plaques convexe entraîne localement dans la plaque chevauchante une extension horizontale parallèle à la frontière qui provoque localement le retrait du front de cette plaque et la réduction de la pression inter plaque. En imposant cette déformation extensive à la plaque chevauchante dans un modèle expérimental thermomécanique 3D nous avons obtenus l'exhumation locale des roches UHP/BT et avons pu étudier en détails son mécanisme.

>Magister Scientiae - MSc / The reservoir quality of the Orange Basin, offshore South Africa is known to be immensely impaired by the presence of authigenic minerals. The collective effects of burial, bioturbation, compaction and chemical reactions between rocks, fluid and organic matter conclusively determined the quality of reservoirs within the Orange basin. The aim of this study was to provide information on the quality of reservoirs within the Orange Basin. Data used to conduct this study include wireline logs (LAS format), well completion reports and core samples from potential reservoir zones of wells K-A2, K-A3 and K-E1. To accomplish the aim, petrophysical parameters were calculated, such as porosity, permeability and water saturation. Besides, depositional environments were identified using gamma ray log and core logging techniques. Thirdly, petrographic studies were supporting techniques in understanding how various minerals and diagenetic processes play a role in reservoir characterisation. Geophysical wireline logs (Gamma ray, Resistivity, Bulk density and Caliper) allowed for the estimation of the three main reservoir properties; namely: porosity, water saturation and permeability. The porosity calculations revealed a range of 3-18% for well K-A2, 2%-13% for well K-A3 and 3%-16% for well K-E1. The permeability’s ranged from 0.08-0.1 mD and 0.001-1.30 mD for K-A3 and K-E1, respectively. Thus, the findings of the petrophysical evaluation of the wells in Interactive Petrophysics indicated that the reservoir intervals of wells K-A2, K-A3 and K-E1 are of poor to good quality. Based on the core analyses, the depositional environment is mostly shallow marine, specifically tide dominated for well K-A2, sandstone channel for well K-A3 and intertidal environment for well K-E1. These environments were confirmed by XRD, revealing glauconite as the prominent mineral.

Univ., Diss.--Bremen, 2005.

The structure and geomorphology of active orogens evolves on time scales ranging from a single earthquake to millions of years of tectonic deformation. Analysis of crustal deformation using new and established remote sensing techniques, and integration of these data with field mapping, geochronology and the sedimentary record, create new opportunities to understand orogenic evolution over these timescales. Timor Leste (East Timor) lies on the northern collisional boundary between continental crust from the Australian Plate and the Banda volcanic arc. GPS studies have indicated that the island of Timor is actively shortening. Field mapping and fault kinematic analysis of an emergent Pliocene marine sequence identifies gentle folding, overprinted by a predominance of NW-SE oriented dextral-normal faults and NE-SW oriented sinistral-normal faults that collectively bound large (5-20km2) bedrock massifs throughout the island. These fault systems intersect at non-Andersonian conjugate angles of approximately 120° and accommodate an estimated 20 km of orogen-parallel extension. Folding of Pliocene rocks in Timor may represent an early episode of contraction but the overall pattern of deformation is one of lateral crustal extrusion sub-parallel to the Banda Arc. Stratigraphic relationships suggest that extrusion began prior to 5.5 Ma, during and after initial uplift of the orogen. Sedimentological, geochemical and Nd isotope data indicate that the island of Timor was emergent and shedding terrigenous sediment into carbonate basins prior to 4.5 Ma. Synorogenic tectonic and sedimentary phases initiated almost synchronously across much of Timor Leste and <2 Myr before similar events in West Timor. An increase in plate coupling along this obliquely converging boundary, due to subduction of an outlying continental plateau at the Banda Trench, is proposed as a mechanism for uplift that accounts for orogen-parallel extension and early uplift of Timor Leste. Rapid bathymetric changes around Timor are likely to have played an important role in evolution of the Indonesian Seaway. The 2010 Mw 7.1 Darfield (Canterbury) earthquake in New Zealand was complex, involving multiple faults with strike-slip, reverse and normal displacements. Multi-temporal cadastral surveying and airborne light detection and ranging (LiDAR) surveys allowed surface deformation at the junction of three faults to be analyzed in this study in unprecedented detail. A nested, localized restraining stepover with contractional bulging was identified in an area with the overall fault structure of a releasing bend, highlighting the surface complexities that may develop in fault interaction zones during a single earthquake sequence. The earthquake also caused river avulsion and flooding in this area. Geomorphic investigations of these rivers prior to the earthquake identify plausible precursory patterns, including channel migration and narrowing. Comparison of the pre and post-earthquake geomorphology of the fault rupture also suggests that a subtle scarp or groove was present along much of the trace prior to the Darfield earthquake. Hydrogeology and well logs support a hypothesis of extended slip history and suggests that that the Selwyn River fan may be infilling a graben that has accumulated late Quaternary vertical slip of <30 m. Investigating fault behavior, geomorphic and sedimentary responses over a multitude of time-scales and at different study sites provides insights into fault interactions and orogenesis during single earthquakes and over millions of years of plate boundary deformation.

Thesis (D. Min.)--Abilene Christian University, 1994. / Includes abstract. Includes bibliographical references (leaves 172-176).

Thesis (Ph. D.), Memorial University of Newfoundland, 1998. / Bibliography: v. 1, leaves 250-287. Also available online.

Thesis (Ph. D.)--University of Canterbury, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 250-261). Also available via the World Wide Web

La thèse aborde plusieurs problématiques liées à la conservation, l'entretien et la restauration des édifices en Grèce aux époques classique et hellénistique, à partir des cas de Delphes et de Délos, deux sites qui ont fourni une riche documentation épigraphique et archéologique. D'un point de vue pratique, il est question des techniques et méthodes utilisées pour prévenir les dégâts et réparer ou entretenir les bâtiments. Les différents acteurs de l'entretien des édifices sont identifiés, ainsi que leurs rôles respectifs. D'un point de vue économique, sont étudiés les sources et moyens de financement et la part des dépenses que constitue, pour un sanctuaire ou une cité, l'entretien de ses bâtiments. Le vocabulaire des inscriptions est étudié en détail afin, notamment, de mieux cerner les enjeux sociaux et politiques liés aux restaurations architecturales. / Doctorat en Histoire, histoire de l'art et archéologie / info:eu-repo/semantics/nonPublished

Permanent brittle deformation of rocks of the upper crust is often manifested in the growth of fractures, or sliding along fractures, which may subsequently be intruded by magma and other fluids. The brittle deformation structures described here include faults, joints and dykes. Brittle deformation structures along passive continental margins result from continental fragmentation and related uplift, as is seen around the southern African margins in response to Gondwana break-up. In many cases the fragmentation is accompanied by significant magmatic events, for example the Cretaceous mafic dyke swarms that form major components of the South Atlantic Large Igneous Province (LIP) and originated during the break-up of West Gondwana (Africa and South America). The magmatic events accompanying the break-up of Gondwana resulted in crustal extension and the formation of joint systems and dyke swarms that exhibit distinct geometric features that appear to display fractal patterns. This work analyses the relationship between the Henties Bay-Outjo Dyke Swarm (HOD) on the west coast of Namibia, and the Ponta Grossa Dyke Swarm (PG) on the coast of Brazil, both of which formed ca. ~130 Ma, to test for their co-linearity and fractal geometry before and during West Gondwana break-up. This was achieved by reconstructing Gondwana‘s plates that contained the PG and HOD swarms, using ArcGIS and Gplates software. The dyke analyses was complemented with a comparative study of joints of the Table Mountain Group quartzites (TMG, ca. 400 Ma) in the Western Cape Province and Golden Valley Sill (GVS, ca. 180 Ma) in the Eastern Cape Province, to compare their fractal patterns and possible relationship. Mapping of joints was carried out in the field with the use of a compass and GPS. The HOD trend is positioned largely NNE > NE, but a NW dyke trend is also common. The dominant joints in the TMG trend NNW > WSW and the GVS joints trend WNW > NNE and others. The GVS and HOD orientations appear strongly correlated, while TMG shows no simple orientation correlation with GVS and HOD. The lack of correlation is attributed to the TMG‘s formation in different host-rocks with variable anisotropy and/or the presence of different mechanical processes acting at a different time in geological history. All mapped dykes and joints were analysed to test for fractal geometry. The fractal dimension results of about 18605 HOD dykes from microscopic to mega scale (0.1 mm – 100 km) shows fractal patterns that range between Df = 1.1 to 1.9; and the fractal dimension of about 1716 joints in the TMG and about 1026 joints in the GVS at all scales range between ca. Df = 1.6 to 1.9. The similarity of the fractal patterns indicates that joints and dykes may have formed in response to similar tectonic stress events; and similar orientations may indicate that joints pre-dated the dyke intrusions. However, the data also indicate that dykes are not always related to pre-existing joints.

Mountain pine beetles (Dendroctonus ponderosae) are native insects that have decimated millions of hectares of mature pine (Pinaceae) forests in western North America. The purpose of this study is to investigate biophysical and climatic correlates of Mountain Pine Beetle (MPB) insect outbreaks in the Crown of the Continent Ecosystem (CCE) from 1962 to 2014 using Aerial Detection Survey (ADS) and climate data. Specific objectives were: 1) to develop statistical models to determine how selected biophysical correlates (slope, aspect, elevation, and latitude) and 2) to understand how local and global climate variables relate to the extent of the MPB infestations in the CCE, and 3) to contextualize the results of the models with historical climate data. Overall, the major findings of this study are: 1) despite its limitations, the ADS data seems suitable for analysis of beetle damage with respect to climate and topographic factors, on a regional scale, 2) there appears to be a link between local biophysical factors and winter precipitation and TPA within the CCE, and 3) a combination of a negative-phase PDO and La Niña is important in forecasting a decline in MPB spread, during a given year. This study is the first, to our knowledge, to explore spatio-temporal patterns of MPB outbreaks using biophysical factors, and both local and global climate variables, over a fifty-year timespan in the CCE. In the future, additional geospatial analyses may enable a landscape assessment of factors contributing to variability of MPB infestation and damage as this insect continues to spread. / Master of Science