<p> Geophysical studies of the northwest trending Sudbury olivine diabase dikes, to the south of Coniston, Ontario establish a deformation zone, within the Southern province up to 10 km from the Grenville Front. Paleomagnetics reveal two directional groups within the dikes; those with a NRM direction of 300°/32° representing the primary magnetization of the dikes and those dikes with a Grenville overprint direction of 116°/56°. The deviation in direction of the two groups, in relation to previous studies (Palmer et al., 1977) is interpreted to be due to fault block movement. Aeromagnetics reveal extensive ductile and brittle deformation in the dikes as they approach the front. The general orientation of deformation is to the northeast. </p> / Thesis / Bachelor of Science (BSc)

<p> The last major episode of deformation occurred in the area studied during the Grenville orogeny (~1000 Ma ago). Deformation of this zone is characterized by a northeast trending penetrative foliation and southeast plunging mineral lineation which increase in intensity and decrease in inclination from northwest to southeast. The deformation was imposed during reverse fault movement in which the southeastern block (the Grenville province) was vertically displaced on the order of 20 kilometers above the adjacent block (the Southern province). The Killarney belt of granites, which separate the Grenville province from the Southern province in this area, are intrusive into the Huronian metasediments and predate the Grenville orogeny. These granites also show evidence of Grenvillian deformation. </p> <p> Paleopiezometry has shown that the differential stress during deformation increases from less than 1 Kbar to more than 6 Kbar from southeast to northwest. The microstructural strain features in quartz and felspar and the mineralogy indicate that a temperature change o£ 400 C is associated with this change in differential stress. Kinematic analysis of mylonites supports the reverse fault model o£ the Grenville Front. </p> / Thesis / Master of Science (MSc)

No description available.

My graduate thesis is a study of telluric and tectonic architecture. These two ideas inspired me to design a baseball stadium for the town of Blacksburg, Virginia that portrayed the contrasting concepts "of the earth" and "of the sky." / Master of Architecture

The human form becomes the bearer of my inspiration, revealing a cosmology within itself, appealing to the idea of understanding the body and implementing its essence into architecture. The lessons found in the tectonic of one's body will assist in discovering an integral logic that may translate in the design of the building. Living organisms inspire architectural posture that generate my architectural ideas. Architecture considered, in a very natural way reflects humans. I try to find a methodology inspired by natural organisms, finding the human body the most beautiful and functional of all natural objects. The structure begins to illustrate the innovation of the materials being employed to a different type of solution to a structural problem. The truth of materials, and honesty in the expression of structure reflect the movement of the object. / Master of Architecture

Neoproterozoic volcanic, sedimentary and volcano-sedimentary rocks of central Wadi Allaqi were deformed and metamorphosed to greenschist facies during the Pan-African orogeny. Three major, geochemically and lithostratigraphically distinct, tectonic-stratigraphy Successions with an intermediate tectonically-emplaced unit of ophiolitic rocks (Gebel Taylor Wedge), which have been metamorphosed to blueschists facies prior to emplacement, are recognised. The tectonic pile has been intruded by four granitic plutons and basic igneous sills, which were emplaced at various stages in the tectonic history. A series of large-scale thrust duplexes with a few major nappe-like folds and shear-zones, the most conspicuous of which is the Allaqi Shear-zone, structurally dominate the area. A complex polyphase structural history has been deduced consisting of earlier ductile and late more brittle deformation phases and this has been related to the regional metamorphic development. A gold mineralized quartz vein system was emplaced syn-tectonically along the first deformation (D1) shear-zones. Data from structures, petrography, fluid inclusions and stable isotopes of oxygen and hydrogen tend to support a metamorphic provenance for the auriferous fluids. The petrological, geochemical and structural evidence strongly support a back-arc basin environment for the sedimentary development of central Wadi Allaqi before the Pan-African Orogeny. A single Wilson Cycle is proposed for the evolution of the area, in which following an extensional phase, during which the marginal elements of the ancient Mozambique Ocean (in the sense of Dalziel 1991) were developed. Back-arc sedimentary rocks and volcaniclastic rocks were metamorphosed and transported as a thrust-duplex system northward over the Nile Craton and any associated marginal sedimentary sequence.

A área objeto da presente pesquisa encontra-se na parte centro-oeste de Moçambique, entre os paralelos 16 o e 20 o S e meridianos 33 o e 34 o E, e corresponde ao extremo sul do Cinturão de Moçambique. Inclui a borda leste do Craton do Zimbabwe e encontra-se limitada a leste pelas formações sedimentares Fanerozóicas do Karoo. A região tem uma importância geotectônica fundamental, por se localizar numa junção crítica entre as grandes unidades tectônicas Pan -Africanas dos cinturões de Moçambique e de Zambezi. Embora exista um controle geológico relevante, em virtude dos mapeamentos geológicos detalhados e das informações trazidas nos relatórios do Consórcio GTK, as relações entre as unidades tectônicas são muito complexas e o número de datações que se faziam disponíveis era pequeno e restrito às áreas limítrofes da borda do cráton Arqueano. Em vista disso, o objetivo principal deste trabalho foi o de efetuar um estudo geocronológico robusto, utilizando essencialmente monocristais de zircão, extraídos das rochas regionais, e produzir uma série de determinações de idade U-Pb, pelos métodos LA-ICP-MS e SHRIMP, com a finalidade de definir épocas precisas de cristalização de rochas magmáticas e de recristalização de rochas metamórficas, além de buscar elementos para estimar a proveniência e colocar limites temporais para as unidades metassedimentares. Em adição às datações U-Pb em zircão, foram realizados estudos básicos complementares de petrografia, bem como de datações K -Ar em minerais separados, datações Sm-Nd em granadas, estudos especiais de microssonda analítica para estudos geotermobarométricos, e de geoquímica isotópica de Nd e de Hf como indicadores de ambiente tectônico. As datações efetuadas nas rochas ortoderivadas confirmaram algumas idades obtidas anteriormente pelo Consórcio GTK, próximas de 1050 Ma para os granitóides do Complexo de Báruè e de 850 Ma para os da Suite de Guro. Além disso, datações em zircões detríticos de metassedimentos relacionados com o craton do Zimbabwe confirmaram a idade pelo menos Mesoproterozóica do Grupo Umko ndo, e a idade neoproterozóica do grupo Rushinga. Resultados inesperados foram encontrados para as rochas de alto grau, paragnaisses, granulitos e migmatitos dos Grupos Macossa, Chimoio e Mungari, para as quais as condições do metamorfismo foram estimadas entre 4-6 kbr e 700-800 o C, através de estudo geotermobarométrico. Os zircões detríticos dessas rochas indicaram idades máximas do Neproterozóico, demonstrando aloctonia e proveniência de Leste. Além disso, as idades do metamorfismo dessas unidades, a partir de isócronas Sm-Nd em granadas e datações U-Pb nas bordas metamórficas de cristais de zircão, revelaram-se muito jovens e muitas delas próximas de 500 Ma, já no Cambriano. Além disso, o evento tectono-termal Pan-Africano, entre ca. 500-600 Ma, superposto em toda região de estudo, foi registrado também por idades de resfriamento K-Ar abaixo de 500 Ma. Dos resultados obtidos foi possível estabelecer tentativamente uma história da evolução tectônica da região centro-oeste de Moçambique e considerá-la num contexto continental, como segue: Nos limites leste e norte do cráton do Zimbabwe ocorrem os grupos marginais tectonicamente autóctones de Umkondo (Mesoproterozóico) e Rushinga (Neoproterozóico). Mais para leste, as demais rochas compreendem terrenos alóctones formados por material de idade variada, em grande parte Mesoproterozóica, sotoposto a rochas supracrustais com zircões detríticos do Neoproterozóico (Macossa, Chimoio e Mungari). Tentativamente, duas grandes nappes estão sendo sugeridas, definindo contatos de justaposição tectônica com empurrões para Oeste, em direção ao Craton do Zimbabwe. Uma delas ao norte, denominada Nappe de Mungari, seria correlacionável com as unidades tectônicas da parte NW de Moçambique, com idades principalmente Mesoproterozóicas. A segunda, denominada Nappe Macossa-Chimoio, seria correlacionável com o Bloco de Nampula, que ocorre ao sul do Lineamento do Lúrio, no NE de Moçambique. A zona de contato tectônico entre as duas nappes e as rochas Arqueanas do craton, com direção aproximada N-S, representa a provável sutura principal do Cinturão de Moçambique na região estudada. / The study area is located in the central-western part of Mozambique, between 16 o - 20 o S latitude and 33 o - 34 o E longitude, and corresponds to the southernmost part of the Mozambique Belt. It includes the eastern border of the Zimbabwe Craton and it is limited towards the East by the Phanerozoic formations of the Karoo System. The region is fundamentally important for the African tectonic context, because it belongs to the critical junction among the very large Pan-African units of the Mozambique and Zambezi belts. Although a relevant geological control is available, due to the regional mapping done by the GTK Consortium, the tectonic relations within the area are complex, and the geochronological control was insufficient and restricted to the vicinity of the cratonic border. Because of this, the main objective of this work was to carry out a comprehensible and robust geochronological study, using zircon crystals and producing a series of U-Pb dates, by means of LA-ICP-MS or SHRIMP methods, in order to establish some precise magmatic crystallization or metamorphic recrystallization ages, as well as to estimate provenance and maximum ages for the meta-sedimentary units. In addition, some K-Ar ages on micas and some Sm-Nd ages on garnets were obtained, and a special Nd and Hf isotopic, and a few geothermobarometric studies were also made as indicators of the tectonic envi ronment. Some ages of orthogneisses confirmed some previously known results obtained by the GTK Consortium, near 1050 Ma for the granitoids of the Barue Complex and 850 Ma for those of the Guro Suite. Moreover, ages of detrital zircons of meta-sediments related to the Zimbabwe Craton confirmed at least a Mesoproterozoic age for the Umkondo Group and a Neoproterozoic age for the Rushinga Group. Unexpected ages were found for the high-grade rocks, paragneisses, granulites and migmatites of the Macossa, Chimoio and Mungari Groups, for which the P-T conditions were estimated between 4 - 6 kbr and 700 - 800 o C. Detrital zircons from these rocks indicated Neoproterozoic maximum ages of deposition, demonstrating allochthony and provenance from the East. Moreover, from U-Pb dating of zircon overgrowths, and Sm-Nd garnet-whole rock isochron dates, their age of metamorphism was found to be very young, about 500 Ma, already in the Cambrian. Finally, the Pan-African tectono-thermal event, which affected the entire area, yielded still younger K-Ar cooling ages, below 500 Ma. From the geochronological context, it was possible to make a preliminary tentative suggestion for the tectonic history of the central-western region of Mozambique, as follows: At the northern and western borders of the Zimbabwe Craton, the marginal sequences of Umkondo (Mesoproterozoic) and Rushinga (Neoproterozoic) occur. Towards the east, allochthonous terrains which include variable material of mainly Mesoproterozoic age are found, overlain by supracrustal rocks with Neoproterozoic detrital zircons of the Macossa, Chimoio and Mungari Groups. Two large nappes are envisaged, with tectonic juxtaposition towards the Zimbabwe Craton. The Mungari Nappe, in the north, would correlate with the tectonic units encountered in the NW portion of Mozambique. The Macossa-Chimoio Nappe, in the south, would correlate with the Nampula Block, which occurs to the south of the Lurio Belt in the NE portion of Mozambique. The tectonic contact between each one of the nappes a nd the Zimbabwe Craton is here considered as the probable principal suture of the Mozambique Belt in the studied region.

An integrated field, petrographic , structural , and geophysical analysis of the Panther Creek half -graben (PCHG), in east -central Idaho, was undertaken to determine its tectonic origin. Two competing theories as to the origin of the PCHG exist. One suggests that it formed as part of the TransChallis fault system (TCFS) , a system of northeast-trending normal faults, eruptive centers, and graben that formed in Middle Eocene time. The graben of this system are bounded by northeast-striking normal faults, and show evidence of syn-tectonic deposition of basin-filling volcanic strata. The other theory suggests that the PCHG may have evolved as a result of a post-Challis volcanic extension event (Late Eocene to Early Oligocene). Graben of this event are bounded by NNW-striking normal faults, and Challis volcanic strata are uniformly tilted; this evidence suggests post-volcanic basin formation. This study demonstrates that formation of the PCHG was mostly synchronous with volcanism and that there was very little post-volcanic deformation. Other conclusions of this research are 1) Rates of slip on basin-bounding faults were high, and slip was episodic. Slip occurred on both NE and NNWstriking faults, but more occurred on the NE-striking basin-bounding fault. This is consistent with the dominant NE strike of faults within the TCFS. 2) Most of the older volcanic units in the basin dip more steeply to the SE than overlying younger units , this is evidence for synvolcanic deposition . 3) There is significant hanging wall deformation in the form of folds and normal faults, particularly in the northern and southern portions of the basin . 4) Paleocurrents determined from provenance studies and imbricate fabric in exposed conglomerate beds indicate a flow direction largely to the northwest. This paleocurrent flow crosses the strike of the syn-extensional basin-filling units . 5) The composition of the clasts in the post-volcanic basin -fill deposits suggests that the thick volcanic units preserved in the basin never blanketed highlands NE, E, and SE of the basin and that the footwall of the basinbounding fault system was the main source of sediment in the basin. 6) The magnetic and bouguer gravity surveys indicate a sizable intrusion (most likely related to the nearby Casto pluton) beneath the west-central portions of the basin. The intrusion(s) may be responsible for east-plunging folds in the tuff of Castle Rock. 7) Work initiated during this study to determine the 40Ar/39Ar incremental-release mineral ages and the polarity of the tuff of Castle Rock and the tuff of Challis Creek will help determine the relationship between these two units and will precisely date basin development. However, it is clear that the basin was nearly fully formed by the end of Challis volcanism.

The majority of economic gold deposits in NSW are associated with Ordovician-aged igneous rocks and are examples of the Cu-Au porphyry-skarn-epithermal association commonly developed in convergent margin to orogenic settings. They are among the oldest porphyry Cu-Au deposits in the Pacific Rim region. They are similar to younger deposits in terms of tectonic setting and structure, but the largest are chemically distinct, being associated with shoshonite magmas (Cadia, Ridgeway and Northparkes). The Lachlan Fold Belt (LFB) porphyries are subdivided into four sub-groups based mainly on their age relative to development of the Lachlan Transverse Zone (LTZ) structure. Two subgroups pre-date the LTZ, one group is syn�LTZ and one group post-dates the LTZ. No mineralisation has been found or reported among pre-I.TZ porphyries. but it is common in post- . l Z_ porphyries. Petrographic analysis and microprobe results establish a wide range of primary and secondary features within the Ordovician rocks examined in this study. Cale alkaline to shoshonitic affinities are supported by the variable abundance of primary K-feldspars. Primary mineral phases such as pyroxenes and igneous magnetite provide an indication of fractioning mineral assemblages responsible for igneous trends in magma chemistry. The hydrothermal mineral assemblages documented in these LFB study areas are characteristic of younger Cu-Au Porphyry style mineralisation. As expected, the most pervasive alteration is associated with highly mineralised shoshonitic Ordovician rocks at Ridgeway, and Cadia. the less strongly mineralised calc alkaline Ordovician rocks at Cargo. Copper Ilill and Fairholme. are correspondingly less strongly altered overall. although secondary mineral assemblages are locally abundant. Many varieties of oxides and carbonates are observed at the different study localities. Most of the studied samples conform to igneous chemical trends because they are weakly altered, although post magmatic processes, such as veining, are detectable in certain trends. The K2O enrichment of the studied samples is consistent with subductionmoditied mantle wedge sources. A few effects, such as the high Fe203 contents of some Ridgeway samples, probably reflect porphyry-style hydrothermal alteration processes. Host rocks at the Cadia and Ridgeway are entirely alkalic on the K2O versus SiO2 plot and shoshonitic on the Total Alkalies versus SiO2 plot. Igneous rocks at the other deposits display a range of compositions between low K tholeiites to shoshonites that in some cases reflects multiple igneous suites. The LREE and L1LE enrichments, and HFSE depletions (Nb, Ta and Ti) of the magmas associated with these deposits are characteristics of a subduction-related tectonic setting. They all fall in the volcanic-arc granite and syn-collisional granite field of the Nb-Y tectonic discrimination diagram. Several magma types are identified by differences in the HFSE and REE trends. Differences in the extent and style of magma fractionation are evident in the trace element data. The Ridgeway samples define a wider range of trace element concentrations than the Cadia samples that may indicate a greater extent of fractionation during emplacement of the Ridgeway magmas. Fairholme samples display a high Nh and /If trends that are distinct from the main fields on Zr variation diagrams. Compositional differences between larger Cu-Au deposits, Cadia-Ridgeway and smaller deposits, Copper Ifill, Cargo and Fairholme are evident in terms of Nb-Ta depletion and variation. The smaller deposits show constant Nb/Ta or negative Nb/Ta trends that extend to high Nb. The larger deposits display positive Nb/Ta trends that do not extend to high Nb. This distinction reflects a difference of preferential incorporation of Nb in a mineral phase (magnetite). Comparisons between Cadia-Ridgeway and other shoshonite (altered samples of Bajo de la Alumbrera, Argentina), calc alkaline magmas from New Zealand and rocks from other areas indicate that Nb/Ta is not directly correlated with the shoshonitic classification, K2O vs. SiO2, and that the Cadia-Ridgeway Nb and Ta variation is not the result of alteration. The fact that the weakly altered LFB Capertee shoshonites exhibit a narrow range of Nb and low Nb/Ta suggest the shoshonite trend for the LFB as a whole is a steep one on the Nb/Ta versus Nb plot. The results of this study could provide important information for exploration within the LFB. Only the Cadia and Ridgeway deposits display a wide range of Nb/Ta values and lack the near-horizontal trend seen for other localities associated with smaller deposits. The tectonic evolution of the LFB is a major factor contributing to occurrence of large porphyry Cu-Au deposits. The sequence of important events, however, commences with sub-crustal generation of oxidised magma and finishes with efficient Cu-Au accumulation by hydrothermal processes at favourable structural sites. The increase in Au-Cu deposit size from small (Copper Hill-Cargo) to world class (Cadia-Ridgeway) indicates the importance of magma composition during this process. The most obvious differences between the Cadia-Ridgeway and New Zealand rocks is that the latter are volcanic in origin and associated with an arc-back arc system. Therefore, they did not form in a tectonic regime suitable for the evolution of porphyries and the focussed movement of hydrothermal fluids during dilatant episodes. As a result, they are not linked to mineralisation despite having Nb-Ta and Nb/Ta variations that are typical of the high oxidation states in Au-prospective magmas of the LFB.

The Alexander terrane is an allochthonous terrane within the North American Cordillera. New structural mapping and geochronology within the southern Alexander terrane in the vicinity of Porcher Island provides evidence for two major tectonic events. The oldest is Late Silurian to Early Devonian magmatism and deformation assigned to the Klakas orogeny. The area has subsequently been affected by mid-Cretaceous conjugate shear zones potentially associated with tectonic escape. Northwest-striking sinistral shear zones characterize mid-Cretaceous deformation in the western Coast Belt south of Prince Rupert in north coastal British Columbia. Structurally focused mapping and geochronology has revealed a component of lateral extension to this deformation. General flow characteristics of the shear zones are identified by comparison of fabric patterns to published models for fabric development in shear zones. U-Pb ages from synkinematic dykes constrain motion on northwest-striking sinistral transpressional shear zones, including the Useless, Barrett and Salt Lagoon shear zones, to ca. 104 – 96 Ma, and dextral transpression on the north-striking Telegraph Passage shear zone to ca. 97.6 ± 0.2 Ma. The geometry, kinematics, and coeval nature of these shear zones suggests that they formed in part as a ductile conjugate set. The presence of similarly-oriented conjugate shear bands in the apex zone between sinistral and dextral shear zones further reinforces this interpretation. The orientation of these conjugate sets indicates a component of north-northwest east-southeast extension. The conjugate shear zones merge together into the Grenville Channel shear zone, a sinistral transpressional shear zone with high strike-parallel stretch. A U-Pb age of 103 ± 32 Ma from a synkinematic dyke in the Grenville Channel shear zone coincides with a previously published Lu-Hf age of 102.6 ± 3.7 Ma on synkinematic garnet. Overall, structural and geochronological data from Porcher Island and surrounding area in north coastal British Columbia indicate that mid-Cretaceous deformation was characterized by ENE-WSW (orogen normal) shortening and NNW-SSE (orogen parallel) extension. This local strain regime is consistent with large-scale mid-Cretaceous tectonic escape as proposed for the northern Cordillera at that time, expressed in coeval sinistral faulting in the Coast Belt and dextral faulting in the northern Omineca belt. The Late Silurian to Early Devonian Ogden Channel complex is a mafic to intermediate metaplutonic-metamorphic complex within the southern Alexander terrane on southern Porcher Island and adjacent Pitt Island in north coastal British Columbia. Lithological characteristics of the complex suggest that it represents the mid-crustal roots of a volcanic arc. An age of 413.3 ± 2.5 Ma from a comparatively weakly deformed quartz diorite dyke indicates that the synkinematic Ogden Channel complex is at least in part Early Devonian in age, corresponding to the Klakas orogeny that affected the Alexander terrane in southeast Alaska. Crosscutting relationships indicate that individual intrusions within the Ogden Channel complex were emplaced syn- to post-kinematically with respect to southwest-vergent sinistral reverse deformation (present coordinates). The structural and lithological characteristics of the Ogden Channel complex are consistent with the interpretation that this part of the Alexander terrane was located in the upper plate of a northeast-dipping subduction zone, which culminated in the Klakas orogeny.