The quest to answer fundamental questions and solve complex problems is a principal tenet of Earth science. The pursuit of scientific knowledge has generated profuse research, resulting in a plethora of information-rich resources. This phenomenon offers great potential for scientific discovery. However, a deficiency in information connectivity and processing standards has become evident. This deficiency has resulted in a demand for tools to facilitate and process this upsurge in information. This ontology project is an answer to the demand for information processing tools. The primary purpose of this domain-specific ontology and knowledge base is to organize, connect, and correlate research data related to brittle deformation microstructures. This semantically enabled ontology may be queried to return not only asserted information, but inferred knowledge that may not be evident. In addition, its standardized development in OWL-DL (Web Ontology Language-Description Logic) allows the potential for sharing and reuse among other geologic science communities.

The Kinsevere mine is a copper deposit located in the Democratic Republic of Congo (DRC), within the Central African Copperbelt. This area is situated in the Katangan basin within the SE portion of the Lufilian Arc, which is a large, arcuate structure that extends from SE Angola, across the DRC, and into NW Zambia. The purpose of this study is to characterise the brittle deformation observed around the Kinsevere copper deposit to lead to an understanding of the deformation history of the area. This is accomplished by analysing fault-slip and fold data to help understand the relationship between regional palaeostress, faulting and folding present in the mine vicinity. This study also attempts to characterise fracture-controlled copper mineralisation within the interpreted geodynamic context of the area. The broader objective of this study is to relate the structural observations from Kinsevere to the deformation history of the Lufilian Arc. This study uses the right dihedral method to analyse four categories of brittle structures. The structural types analysed include slickensided faults, mineralised joints, and unmineralised joints and shear fractures. The data suggests that the palaeostress associated with the formation of brittle structures in the Kinsevere area occurred during three deformation events. The first event is characterised by a compressional stress regime which occurred during the early stage of the Kolwezian phase (D1). The second event is characterised by a strike-slip stress regime that formed as the result of clockwise rotation of the earlier (D1) compressional regime. Two fault-slip vectors were observed on the strike-slip fault planes, indicating that a reactivation occurred during the Monwezian phase (D2). The final structural event was characterised by the development of an extensional stress regime. This was associated with North-South oriented extension and is related to the East African Rift System (D3). These interpreted events correlate well with the geodynamic context related to the Lufilian orogeny. Another line of evidence that supports this structural interpretation is the presence of evaporitic minerals observed in the stratigraphic units surrounding the brecciated zones such as the RAT and the CMN. The structural association of these evaporitic minerals may be related to pre-existing, salt-bearing units, which were dissolved during an early compressive (D1) phase of the Lufilian orogeny. However, the contact between the Grey RAT and the Red RAT (distal from the breccia zones) does not show any evidence of faulting, and in the Kinsevere area the Grey RAT is always observed above the Red RAT. This suggests that the Grey RAT may be the uppermost stratigraphic unit of the RAT subgroup, which contradicts some previously published interpretations. Thus, the current structural architecture was probably formed from a combination of two separate mechanisms, including compression-related salt extrusion and the development of thrust faults and folding resulting from the shortening of the Katangan basin. Based on an analysis of the fracture-controlled mineralisation in the study area, it is shown here that most of the stress tensors indicate that these fractures were induced within the compressional stress regime generated by the Lufilian orogeny. This conclusion supports studies which suggest a multiphase origin for the mineralizing fluids active in the Katangan basin. Thus, the age of the copper mineralisation associated with fractures is interpreted to correlate with the timing of the folding event that occurred during the Lufilian orogeny between 540-550Ma. / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

The objective of this project is about a kinematic analysis of a shear zone, specifically a graben structure. The surface of the study area has also been investigated, this is to understand if a faulting reactivation has occurred due to glacial impact. The graben structure is exposed along a road cut, next to the E18 highway at Ekolsund, 14km east of Enköping. The results of the report are based on field studies of the geometrical relationship pattern of fracture planes, relative displacement along fracture and a kinematic analysis of movements along fractures. A high resolution terrain model was acquired in the analyzing of the graben structure formation and to create a geometrical 3D brittle deformation model. This model was applied to reconstruct the deformation process. The area contains a more than 1,1km long dextral NE-trending strike-slip fault feature in a polydeformed Precambrian bedrock. The fault is connected NE to one of the regional structure that delimits the bedrock blocks. The fault is visible both as a topographical feature from the ground and from aerial photos. While the project followed through it was clear that the area had been subjected to reactivation. The evidence for this claim stems from an observed semivertical fracture plane with conjugating subhorizontal striations markers that contain an alternating plunge and trend. Other evidence for a reactivation scenario is the fault gouges that contain horizontal striation as well as steep plunging striation, indicating a dip-slip faulting movement. The main zone of faulting displays lower altitude than the surrounding rock. This indicates an asymmetric graben structure that has been subjected to polydeformation. When analyzing the results, it is concluded that a pull-apart basin event has occurred. It’s highly possibly that it has been undergoing modifications during its geological history, resulting in a polydeformed reactivation of the minor faults outlining the graben structure. / Syftet med denna studie är att utföra en kinematisk analys av en förkastningszon, speciellt där en mindre graben struktur utbildats. Ytan för det studerade området är även det viktigt, det är för att förstå ifall en förkastningsreaktivering har skett i och med en glacial påverkan. Graben strukturen är blottad längs en vägskärning, utmed E18 vid Ekolsund, 14km österut om Enköping. Resultatet av rapporten är baserat på fältstudier med fokus på geometriska relationsmönster hos sprickplan, relativa förskjutningar längs sprickor och en kinematisk analys av rörelser längs sprickor. En högupplöst terrängmodell var erhållen vid analys av grabenstrukturens formation och för att skapa en 3D sprödtektonisk deformationsmodell. Modellen var tillämpad vid rekonstruering av deformationsprocessen. Området innefattar en mer än 1,1km lång dextral NO-orienterad strike-slip förkastning i en polydeformerad Prekambrisk berggrund. Förkastningen är ansluten NO till en av de regionala strukturerna som begränsar berggrundsblocken. Förkastningen är synlig både på marknivå och från flygfoton. Medan projektet fortlöpte blev det tydligare att området blivit utsatt för en reaktivering. Beläggen för detta påstående grundar sig i de observerade semi-vertikala sprickplanen med konjugerande subhorisontala striationer som har alternerande stupning och trend. Andra belägg för ett reaktiveringsscenario är de fault gouge strukturerna som innehåller horisontala striationer såväl som stupande striationer, vilket indikerar på en dip-slip förkastningsrörelse. Huvudzonen av förkastningen uppvisar lägre altitud än kringliggande bergyta. Det här indikerar en asymmetrisk graben struktur som har utsatts för polydeformation. Vid analys av resultatet, så kan det sammanfattas att en pull-apart basin förkastning har inträffat. Däremot är det mycket möjligt att zonen har undergått fler modifikationer under dess geologiska historia, vilket har resulterat i en polydeformerad reaktivering av mindre förkastningar som gett kontur dragen åt graben strukturen.

Dans la partie Nord de la zone de subduction des Petites Antilles, la convergence est fortement oblique alors qu’au Sud elle est frontale. Cette étude vise à comprendre les conséquences de l’entrée en subduction du plateau des Bahamas fortement flottant par l’étude de l'évolution du champ de contrainte dans le NE de la plaque Caraïbes, depuis l’Eocène. Ce travail montre que sur les îles les plus anciennes, l’arc volcanique s'initie à l’Eocène. La migration de l’arc vers sa position actuelle se produit durant la période Miocène inférieur – Miocène supérieur. La période Oligo-Miocène est charnière : le champ de contrainte évolue d'une extension pure parallèle à la fosse de subduction, à une extension radiale. Après une restauration de la déformation régionale, j'attribue ce changement d’état de contrainte, à l’initiation du partitionnement de la déformation dans le NE de la plaque Caraïbe qui accommode la courbure de la fosse faisant suite à l’entrée en subduction du banc des Bahamas. Dans l’archipel Guadeloupéen, les analyses structurales à terre et en mer montrent des régimes en extension pure perpendiculaire à la fosse. Les orientations des failles similaires depuis l’Eocène confirment un fort héritage structural. À l’actuel, dans le coin NE des Petites Antilles, le régime tectonique est décrochant avec une direction d’extension principale orientée NO-SE soit parallèle à la fosse. Dans l’archipel Guadeloupéen le régime tectonique est purement extensif orienté NE-SO perpendiculairement à la fosse. Cette rotation est interprétée comme résultant de l’augmentation vers le Nord de l’obliquité de la convergence du fait de la courbure de la zone de subduction. / To the north of the Lesser Antilles subduction zone, from North to South, the obliquity of the subduction is decreasing. This study is focus on the consequences of the entrance of Bahamas bank buoyant plateau into the subduction by studying stress field evolution in the NE of the Caribbean plate since Eocene. This work show that the volcanic arc activity on Anguilla bank islands begin at the Eocene. The volcanic arc migration toward his actual localisation occurs during early Miocene – late Miocene period. The Oligo-Miocene period is transitional as a switch in the stress field from pure parallel-to-the-trench to radial extension occurs. A restoration of the regional deformation shows that this switch is related to strain partitioning initiation in the upper Caribbean Plate in response to trench bending that followed the entrance of the Bahamas Bank in the subduction zone. In the Guadeloupean archipelago, kinematic analyses onshore and offshore show a pure extension with a perpendicular-to-the-trench σ3. The similar faults orientations since Eocene confirm that inherited structures control strain localisation. At present day, in NE corner of the Lesser Antilles, the NW-SE main extensional direction of strike-slip stress regime is trench-parallel. In the Guadeloupean archipelago, the pure extensive stress regime is trench-perpendicular (NE-SW). These different orientations of the stress field are interpreted to be the result of increasing trench bending to the North responsible for a northern increase of subduction obliquity

Le plan de thèse comprend les objectifs spécifiques suivants: D'après les observations de terrain, la carte géologique structurale sera obtenue en couvrant la zone géoréférencée entre le lac Buenos Aires et la rivière Mayer dans le sud des Andes de la Patagonie, province de Santa Cruz. L'analyse de la provenance a été faite par des études pétrographiques en grès à cinq coupes stratigraphiques représentatives des séquences considérées appartenant au Crétacé inférieur et au Miocène dans le secteur nord du bassin Austral. D'autres études préliminaires de diffraction des rayons X à un profil (appelé Veranada de Gómez). Aussi, deux unités lithostratigraphiques ont été datées et étudiées par provenance des zircons détritiques. Il est prévu de déterminer pour la zone d'étude, le début de l'avant-pays d'étape, et une estimation est obtenue l'âge de l'exhumation des régions d'origine, et donc une approche semi-quantitative à la fois de l'apparition du soulèvement, comme modèles de dispersion des sédiments. L'analyse complète de ces données donnera la structure générale de la dispersion paléogéographique et des sédiments de la bordure nord du Bassin du Sud pour s'harmoniser avec le patron du secteur sud, qui a alimenté la zone d'étude. De plus, une déformation fragile sera étudiée en analysant les failles striaes pour caractériser les déformations dans la zone. / The thesis plan includes the following specific objectives: According to field observations structural geological map will be obtained georeferenced area covering between the lake Buenos Aires and Mayer River in the Southern Andes Patagonian, Santa Cruz province. Provenance analysis were done by petrographic studies in sandstones at five stratigraphic sections representative of the sequences considered belonging to the Lower Cretaceous and Miocene in the northern sector of the Austral basin. Further X-ray diffraction preliminary studies at one profile (called Veranada de Gómez). Also, two lithostratigraphic units were dated and study by detrital zircons provenance. It is expected to determine for the study area, the beginning of the stage foreland, and an estimate is obtained the age of the exhumation of the regions of origin, and thus a semi-quantitative approach at a time the age of onset of uplift, as sediment dispersion models. The comprehensive analysis of these data will give the general pattern of palaeogeographic dispersal and sediments of the northern edge of Southern Basin to mesh with the southern sector pattern, which fed the study area. Moreover fragile deformation will be studied by analyzing faults striaes to characterize the deformation events in the area.

Made available in DSpace on 2015-03-13T17:08:23Z (GMT). No. of bitstreams: 1 LucianoFCJ.pdf: 1898824 bytes, checksum: ceb5971b03c32817c3191b8feacf5ac8 (MD5) Previous issue date: 2001-02-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study describes brittle deformation and seismicity in the Castanh?o Dam region, Cear? State, Brazil. This reservoir will include a hidroeletric power plant and will store about 6,7 billions m3 of water. Five main litostratigraphic unit were identified in the region: gneissic-migmatitic basement, metavolcanosedimentary sequence, granitoid plutons of Brasiliano age, Mesozoic basaltic dike swarm, and Cenozoic fluvial terraces of the Jaguaribe river. The region has experienced several faulting events that occurred at different crustal levels. Faults formed at depths less than about 12 km present left-lateral movement and are associated with epidote and quartz infillings. Faults formed at depths less than 7 km are mainly strike-slip present cataclastic rocks, fault breccia and gouge. Both fault groups form mainly NE-trendind lineaments and represent reactivation of ductile shear zones or new formed faults that cut across existing structures. Seismically-induced liquefaction fractures take place in Cenozoic terraces and indicate paleoearthquakes that may have reached at leat 6,8 MS. In short, this work indicate that the level of paleoseismicity is much greater than one observed in the instrumental record. Several faults are favourably oriented for reactivation and induced seismicity should be expected after the Castanh?o Dam impoudment / O presente estudo descreve os aspectos deformacionais fr?geis e a sismicidade na regi?o que ser? inundada pelo reservat?rio do A?ude do Castanh?o, por??o leste do estado do Cear?. O lago artificial ter? a capacidade para armazenar em torno de 6,7 bilh?es de m3 de ?gua. Tamb?m ? planejada a instala??o de uma usina hidroel?trica de pequeno porte. Cinco principais unidades litoestratigr?ficas foram identificadas na regi?o: complexo gn?issico-migmat?tico, seq??ncia metavulcanosedimentar, granit?ides brasilianos, enxame de diques bas?lticos mesoz?icos e terra?os fluviais do Rio Jaguaribe. As falhas indicam a presen?a de sucessivos eventos de reativa??o em n?veis crustais diferentes. As falhas de n?vel crustal profundo (at? 12 km), apresentam uma cinem?tica transcorrente e s?o associadas com preenchimento de ep?doto ou quartzo. As falhas de n?vel crustal intermedi?rio a raso (at? 7 km), s?o principalmente transcorrentes, estando associadas ? cataclasito, brecha e gouge de falha. Ambos os grupos de falhas apresentam um trend principal NE, que pode representar a reativa??o de zonas de cisalhamento d?cteis ou a exist?ncia de eventos fr?geis cenoz?icos. Na ?rea existem v?rias evid?ncias de sismitos, estruturas geol?gicas geradas por paleossismos, em n?veis conglomer?ticos nos Terra?os Fluviais do Rio Jaguaribe, que indicam a ocorr?ncia de sismos com magnitude 6,8 MS, no m?nimo, na regi?o. Assim sendo, a regi?o que ser? inundada do A?ude do Castanh?o, e sua circunvizinhan?a, no decorrer do tempo j? foi atingida por in?meros abalos s?smicos. T?m-se registros hist?ricos, instrumentais e geol?gicos claros destas atividades. Com base nestas informa??es, pode-se afirmar que a regi?o ? predisposta a ser afetada por tremores de terra. Mas isto n?o significa que a obra do A?ude do Castanh?o futuramente poder? ser atingida ou danificada por algum abalo que venha a ocorrer, pois a constru??o est? preparada para resistir, no m?nimo, aos maiores abalos s?smicos j? registrados at? o presente momento na regi?o